#352: Do Diets Even Work in the Long-term? - A Look at Weight Loss Maintenance

Hello and welcome to Sigma Nutrition Radio. My name is Danny Lennon and you are listening to episode 352 of the podcast. And in these types of episodes, as we are having today, I'm going to be joined by Alan Flanagan, who is our research communication officer here at Sigma Nutrition. And in these episodes, we take one particular topic each week and dive deeply in on that. But we also have our other segments that you enjoy that includes our listener question of the week. We will have our Quack asylum segment where we take a piece of advice that is being given out that has been shown to be quackery or pseudoscience and to show why that is problematic. And then we will end up with some random recommendations of the week. The show notes to this episode are over at sigmanutrition.com/episode352. If you go there, you'll be able to get links to anything that we mentioned throughout this episode. So any of the research papers we discuss, I will link to in the show notes of the episode. And I will also link to any other links relevant to our other segments. And before we get in, I just do want to make one clear clarification at a point in the episode where I misspoke. We talk about a particular paper related to weight loss maintenance in the national weight control registry. And it was a follow-up study done by Thomas and colleagues 2014. But in my discussion of that, I incorrectly referenced a lead author as Diana Thomas, who is also a well-known researcher. Many of you have came across when indeed that paper was published by Graham Thomas of Brown University. So I just want to make that clarification in case you are looking for that paper, but also the gear of clear credit to Graham Thomas at Brown for his work. And so just note that I misspoke at that particular point when I referenced that Diana Thomas rather than Graham. Also, another clarification for another failure on my behalf was for our listener question this week. We got an excellent question about APOE4. And during the discussion, I actually forgotten who sent me in that question. So a big shout out to you, Jessica. Thank you for an excellent question. And my apologies for forgetting that it was you that sent in that question when we were discussing it in this episode. So thank you for sending that in. And I appreciate it. Now with all that preamble, let's get into this week's show. I very much hope you enjoy. Today's topic in focus. If we jump straight into things, today we're mainly going to focus in on weight loss maintenance. And maybe before getting into weight loss maintenance specifically, that needs to be proceeded with a bit of a discussion around weight regain. And I think there's some interesting aspects to cover off this. So at least to me from the outset, it seems that with any of those longer term weight loss programs or interventions, we tend to see a pretty consistent graph of what body weight changes look like. And we see like this almost peak in weight loss within about a six month period followed by this gradual regain over the months and years ahead. And there's various different statistics that we can maybe bring up that very depending on what paper we're going to look at. And when we look at that weight regain prevalence. And there's two sides that how much weight is regained and then in how many people. And that's maybe an interesting caveat. And I think the other aspect I think would be interesting first to jump into would be around how this shapes some of the narrative of dieting doesn't work. And how can there can be quite visivorous debate on that topic where there's maybe merit in different points. Yeah, I think there are two things that are really helpful to try and define or at least be more definitive with what the actual parameters are when we talk about say the statistic of diets don't work or the statistics in relation to weight regain. You know, we typically talk about long term success, right? But that's quite arbitrary. So the question is what's the definition of success and what's the definition of long term. And what I find interesting is when we start to pick at those two concepts and try and put more kind of scientific explanations to both of them. A bit of a different picture emerges. And when we typically talk about success mostly in the research, it'll be defined to say a five to 10% loss relative to initial body weight. When we talk about long term, that's generally defined by in the research as one year. So, you know, we're typically into already two issues, because one is one year is not representative of really the time course of weight regain. And one year is very easy to also mislead in both directions. It's very easy to mislead and say that there's no success in weight loss interventions or that dietary interventions fail, for example. It's also very easy with other studies to make a case that all dietary interventions work and are successful in quote long term success. And neither of those positions are actually helpful, particularly when we have to think about. So if we look at six months trials, for example, you can often get a mean weight loss of between say five to eight kilos, give or take. But you also have a mean regain of between three to six kilos. Now, if you wanted to turn that into a percentage relative to the you could make a case that between 65 and 100% of diets fail. But that's a reflection of the operational definitions that have been given to both the concept of success and also long term, the concept of long term. And so I think it's important to when we look at some of the actual evidence for success. Typically, what you see is that duration of maintenance is an important factor and that's going beyond one to two years. And between two and four years appears quite crucial in that sense. So I think probably it's more appropriate to define a successful maintenance and certainly the context of regain as probably that longer term period, say, between two and five years. And then I think success has to also be defined as relative to the I think what people focus too much on is was there any weight regained at all. And again, that's relative to absolute weight loss. So someone losing five kilos and regaining three is distinctly different to someone losing 15 kilos and regaining five in terms of the magnitude of reduction that's maintained and how that then correlates to risk reduction for cardiometabolic disease. So for me, it's those two operational definitions of what's long term and what's success. And how does that then relate to factors like absolute amount of weight loss, duration of weight loss maintenance. And then we can start looking at the behavioral factors that correlate with those successful maintainers. Right. Yeah, I think that's actually really useful because trying to answer a question of do diets work or not and looking at the statistics of, oh, X percent of diets fail. As you say, that doesn't really make much sense unless we look at some of those different parameters. So I think there's at least three based on what you just said of we need to take into account the duration of what that period of weight loss maintenance is going to be second, the amount of weight regain and probably as a percentage of that weight that was lost. And then when we're looking at a group of people, the prevalence rate of that weight regain, but again, understanding, are we talking about any weight regain, complete week regain or a certain threshold of that because there can clearly be benefit to a situation where someone has lost weight regained some of that weight, but is in still a net negative lower body weight, depending on what that amount is. Right. And so I think having those parameters at the front of our mind can probably start a more accurate reflection of digging through these statistics. Yes, absolutely. What we're ultimately going to be interested in as well is obviously the absolute numbers. Like it's, I think it's fairly pointless to make a case that, oh, well, two percent of people managed to maintain X amount of weight over five years, right? Because we're still coming back to this idea of that's not representative of the majority. But if there is evidence in the literature, which there is, and we'll get into that one or two studies in particular, where over a long term, and in the look ahead trial, for example, we're talking about eight years of follow-up, you know, what are the numbers in that case? And that becomes a bit more encouraging when you start to then dig into some of the correlates of that success, whether that's practitioner count, number of practitioner contacts, and all of this kind of extra stuff. But yeah, I think it's a diffusion point of definition at the start because it is an emotive topic and we tend to have quite a dichotomous pitch forks battle, like a lot of things in nutrition between weight losses never appropriate or ever warranted or ever successful on one side versus weight losses appropriate and all circumstances, everyone benefits from it and it should be recommended ubiquitously. And neither of those positions are necessarily helpful or even accurate characterizations of the research that's there. Oftentimes, I think it's one of those cases where a certain idea gets to still down into a sound bite that then gets perpetuated by a community of people that gets further and further away from the original point that was made. And in this case, that probably happens on both ends of the diets don't work, meme, is really if you wanted a straw man that you could say that's clearly not the case. And a lot of people, particularly in the fitness industry, will do that. So this position is obviously untenable. Of course diets can work. I have clear examples of where they work in a long term setting as well. But if you were to instead steal man that position, you could see clearly where that idea is coming from in the fact that there are some real challenges for people, number one, losing sufficient amount of weight in the first place to being able to maintain that long term. And then three, some of the other downsides that that presents for an individual that you can improve their health without doing so. And I think that's a much stronger position that is actually one that needs to be really carefully considered by maybe more practitioners than currently do so. Yeah, absolutely. I think it comes a way of maybe distilling it is considering. I don't think a lot of people in nutrition generally consider a weight loss as an intervention inherently carrying any risks. So I think a lot of people view it as just benign as an intervention or recommendation. And it's not benign. It's, you know, there are a complex myriad of psychosocial and behavioral factors that all coalesce to influence whether it is appropriate in a given individual and whether in a given individual it will be successful. And we can tease into some of those behavioral correlates in, you know, in the course of the podcast. But I think that that graph that you're talking about of this kind of decrease this five to seven five to 10% within an initial maybe six months to kind of one year period. And then this almost kind of linear regain. What I find interesting is when you when you dig into that time course of regain, you tend to see it almost beginning within the first year. So if we're looking at the difference between people who successfully maintain versus regain, regain is almost evidence evident practically immediately upon cessation of the intervention or within the first year. And if it has started to occur within the first year, it tends to just progress linearly over time. And I think that's also instructive because it suggests that there is this time period of perhaps 12 to 24 to 48 months in which if there is a degree of success and that that's not saying that there is literally zero weight regain. But if as a percentage of weight loss, that is maintained in that period, then the chances of success start to increase almost exponentially. And I think going back to some of Rina Wings research in the 90s. If I remember correctly, once you started and they were looking at regain, once you went over the one year mark or the two year mark, the likelihood, once you were beyond two years, there was a 50% lower chance of regain. And people who maintained to five years had a 71% lower chance of any regain. So there is this time course in this two to five year period that seems to kind of quite capture the protection against regain. And that strengthens linearly over time just as people who start to regain within a year also regain linearly over time. So it's kind of like this competing almost similar kind of trajectory in terms of the time course of when one starts to be successful versus when the other starts to be unsuccessful. It's interesting. It's almost like a lag time effect that you mentioned there of before you start to see what we categorize as actual weight regain, where as things start changing to give that graph. And I think one of Kevin Hall's papers kind of puts some like mathematical models to try and show why this is commonly the case. And that they kind of use the phrase exponential decay of adherence. Yes, you see where you see this change in caloric intake gives that curve that starts changing. And then suddenly as that curve becomes exponential, that's when you see that regain start to head off. So yeah. And one of the interesting things that I found in some of the kind of mid 90s behavioral research. And honestly, I really think this is somewhat of a failing of the research community that this hasn't become a just default kind of almost inclusion or exclusion criteria in in in trials and intervention trials, where the the intervention is to lose weight. One of the if you look at either the lean habits, the western hover research, or also wings research. One thing that was interesting was that in the few studies that quantified baseline behavioral characteristics in relation to factors like disinhibited eating, restrained eating, depression scores, ingesting, number of previous attempts at intentional weight loss. When you stratified that at baseline, when you quantify that as baseline characteristics, they were the characteristics that were predictive of immediate regain once the intervention was over. And this is actually really important because what this is suggesting is that people within interventions who start to regain immediately might have been people who were struggling before an intervention even began. The implication of course is that they never should have been put in the intervention in the first place. But in the absence of screening for those issues, we tends to just assume again, this comes back to this assumption that it's a benign intervention. So people are placed on a diet where we have research going back 20 years that indicates that people who regain almost instantly are people who were behaviorally struggling with diet either displaying high levels of restrained eating or disinhibited eating or depression prior to an intervention. Why would you put someone on an energy restrictive diet? And let's face it, you know, when you look at some of the actual diets that are, you know, the interventions in many weight loss studies, like who would want to eat that? So I think that's a really important caveat. And I think that the idea that we haven't ubiquitously screened people for these factors, and some interventions do, but the majority that I've ever read don't. And I think that's a real failing kind of within the research community, not to consider that this might be something that you then want to exclude people because it would put them at risk. And if we didn't, you know, have people with these behavioral characteristics in interventions might that have changed all of these means that we tend to talk about in terms of absolute weight loss, regain, and all of these other factors. I don't know, and that's purely speculative, but I'd offer that in the absence of screening, we simply don't know, and not knowing the answer to that question, I think is a fairly poor reflection of how seriously we take those issues, and also a reflection of considering the intervention to carry no inherent risk. Yeah, and I think even from an anecdotal perspective, there's many competent practitioners that would pride themselves on trying to identify if someone has a poor relationship with food or other behavioral or psychological demands that may make going on a diet problematic for them, and making sure those are addressed before there is any intervention if there ever is an intervention. And I think, like you said, there's a clear basis for that, and I'm sure we'll get to some of those psychological factors later, but particularly with the internal disinhibition that you mentioned around people eating, maybe in response to their emotions, feelings, and so on. There's at least some of the study that I think one of the papers I looked at was by Lilis, where they showed that during the dieting period, so that weight loss intervention, the people who decreased their internal disinhibition the most during that time, that was predictive of them having the best results off the back end when it came to weight maintenance, which is kind of unsurprising, giving some of the stuff you just said, and that obviously correlated to some of that flexible dietary restraint, which you also mentioned. So I think that's something we can definitely open a tab on and get into, but I think, yeah, they're very important to consider in this conversation. Yeah, I think the fact that what appears to be completely consistent, whether no matter how far back we go with kind of weight loss research and trying to look at the characteristics of successful maintenance or regain, it's all behavioral. It's all behavioral correlates of these two different outcomes, and so really the discussion becomes quite deep into these psychological predictors of success, and also we know that the kind of psychosocial factors are really important when it comes to non-homeostatic control of eating behavior or influences on eating behavior, the word control can be a bit. And then we even get into interesting delionations between so flexible and rigid dietary restraints were generally considered separate psychological constructs. It would appear that they're more of a spectrum of the same construct as opposed to often again in the fitness community, they're kind of portrayed as two separate things, you know, you're flexible or you're rigid, but actually it's a spectrum of behaviors, and that's an important factor because I think it was still the lean habit study, they looked at eight behavioral characteristics at baseline, flexible versus rigid dietary control, and other factors like meal, regularity, eating situation as a behavior, are you sitting down, are you undestracted food choice? And I think at the three-year follow-up, it was participants who had made the most behavioral improvements out of the eight behavioral correlates, they looked at those that made between five to eight behavior changes were the ones that were successful, and the two behaviors not associated with any increased probability of successful maintenance over the three years were rigid control of food intake and restriction of food quantity. And so that sounds like a paradox because we'll, you know, a degree of energy deficit is required, you know, how could these factors play into, you know, a failure to, I don't know, use the word failure here, I want to be careful with my language, but, you know, a weight regain over time, and it appears again that it's a predictive behavioral, carlet, even pre-intervention. It's interesting you bring up that spectrum of restraint because I think this actually can be explanatory in that disconnect between, let's say, the outer edges of the fitness industry and the non-dieting community, and I'm not making a, don't mean to make a generalization there. I mean, for the people who may be attached to black and white of a perspective in either of those cases, some of that disconnect can be related to the idea that a thought any dietary restraint is bad. But on the podcast before, when Jake Kalinardin, who was on, and he's done a lot of good work down in Melbourne, he talked about, well, what really hasn't been looked at all that much within research is when it is really teasing a part when it comes to dietary restraint, instead of looking at restraint versus no restraint, thinking that restraint occurs across the spectrum that you just mentioned, from rigid at one end to completely flexible, and that there may be differences depending on what level of restraint you include. And at least there's plenty of research that would indicate that for many different measures, but applying that to a context like health outcomes for people that are going to be controlling their eating in some manner. And I think that can maybe explain some of the disconnect that can sometimes happen between those two groups. I think that's a really important point because what appears along that construct is that at the more restrictive end of this spectrum, what is actually the problematic kind of cognitive dysfunctionality, so to speak, is dichotomous thinking about food. It tends to correlate to dichotomous thinking about a number of behaviors, but particularly dichotomous thinking about food. And when you go more to the flexible restraint aspect, you don't see that. So what it indicates is that it's the dichotomous thinking towards more the kind of rigid control end of the spectrum, rather than just restraint per se, that's the underlying factor that might predict weight regain. And I think that that's that's that kind of really important distinction. So flexible dietary restraint, the whole concept of dietary restraint might be a distinct concept. It's a maybe this kind of continuum, but there are behaviorally distinct outputs from one end versus the other with restraint per se, not necessarily being bad, flexible restraint being associated with better outcomes than the dichotomous end of the rigid spectrum. And before we dig into maybe more of those psychological factors to kind of round out some of the weight regain issue, you had mentioned that there's almost a threshold that we need to go beyond in terms of long-term interventions, or at least there's something to be gleaned from having several years of follow-up. And I know you brought the look ahead trial, and maybe there are a few other other specific interventions you think might shed some good light on this. Yeah, I think look ahead is probably putting the best foot forward in a general sense. And so for people unfamiliar with look ahead, it was a diabetes prevention, a whole lifestyle intervention program. If you look at the mean weight loss and what they looked at was an intensive intervention group and kind of a normal traditional treatment. But in the intensive intervention group, if you look at the mean after one year, they lost about eight and a half percent of body weight. And at year four, that was 4.7. So it wasn't entire, and there was still a 50 percent reduction from baseline. But by year eight, they still had four to 4.7. So what this suggested was between year four and year eight, there was a stabilizing effect. And I'm still only talking about the mean here. When you scrutinize the means closer, what emerged was that those that lost over 10 percent of initial body weight in the first year of the intervention were significantly more likely to maintain between five to 10 percent weight loss at four years. Of that, 42 percent had maintained 10 percent of weight loss, which is relative to the wider literature, a fairly staggering number. And 70 percent had maintained over 5 percent of weight loss. And at year eight of the intervention, those numbers were 39 percent had maintained over 10 percent of weight loss. And 65 percent had maintained 5 percent of weight loss. So between year four and eight, even in the groups with the highest amount of weight loss, there was a relatively stabilizing effect of the maintenance and little to no additional regain. And that's putting large numbers of people from that intervention in a range of loss in terms of the five to 10 percent mark, where there was a significant benefit in terms of risk reduction. And we would see that both for cardiovascular disease as well as diabetes. Now, what I find, you know, most interesting in that is when you scrutinize the behavioral factors in the intensive support group in the look ahead trial, they had small groups of 10 to 20 people in the intervention group that met three times a month for the first six months and two times a month up to one year. And then one time every month, so once a month, right up until the eight year mark, but in addition to that monthly in-person session, they had an additional session with a different interventionist, which could have been a dietician or a psychologist or an exercise specialist every month and a potential second contact that was optional by phone or email, which was every two weeks. And they were also in terms of the interventionists, the various multimodal healthcare professionals involved, also canceled to factoring cultural differences, employed different motivational interviewing strategies, self-regulation theory, relapse prevention, and problem solving. And so, yes, this is a really intensive intervention. But for me, the one thing that's always jumped off the page about the kind of, shall we say, responders in the look ahead trial that maintained significant weight loss between five to 10 between years four and eight, up to your four and between years four and eight, was they were the ones who engaged with the most of these various in-person contacts that were available throughout the study period. Maybe as a spoiler for what we would discuss later on, but just to already underscore something you've already said and that this trial even highlights further, is that those behavioral and social support and psychological factors are going to be the main thing driving these success rates, as opposed to worrying too much about specific dietary composition, 20 large degree. And there's some small things we can mention, but I think so much of the focus becomes on, like, what is the best diet for weight maintenance? And again, it's kind of like, what is the best diet for X? It's like, well, that's probably the right question first, but here is even more clearly that there's this overemphasis on diet when it comes to weight loss instead of thinking that change of body composition, long-term weight maintenance comes down to many things beyond diet that are probably even more important or predictive at least. I find look ahead interesting to contrast with, there was an Australian intervention and Purcell was the lead author which wanted to look at rapid weight loss versus gradual weight loss and how that affected weight regain. And there was a bit in total three years of follow-up. And if you look at the practitioner contacts in that intervention, the participants met with the study dietician bi-weekly. Now, because the gradual weight loss was longer than the rapid weight loss group, they actually had more dietician contacts. They had 18 versus six because the rapid weight loss intervention was over 12 weeks and the gradual one was over 36 weeks. But during the maintenance phase up to three years of follow-ups, they met with a dietician at four weeks after the intervention 12 weeks and then every three months thereafter until the end of the study. So if you contrast that would look ahead, look ahead was multimodality, really high level of frequency of practitioner contacts, whereas this intervention was not multimodal, had no behavioral targets, really sparse practitioner contacts. What was interesting was the prescription for if weight started to be regained was to restrict energy again and try and lose the weight that was being regained, which seems if we factor in the totality of literature to be an exercise in total futility, it seems to be really consistent that if people begin to regain weight, possibly the least effective thing to do is tell them to start to restrict energy again with the view to purposely re-losing whatever weight is being regained. That just seems to be an exercise in futility. And I don't know how much we want to get into like the national weight control registry, but I think it's useful to bring up just because there was actually a really good observational study that Diana Thomas, I think, and her colleagues did. So just for some context for people, the national weight control registry is this big investigation of like 10,000 plus people, I think at this point, they have to have lost at least 30 pounds, about 13 kilos and maintain that loss for five years or more. I think the average in that weight loss is actually about 33 kilos or 70-ish pounds. Now what, Diana Thomas' paper was like a 10-year follow-up of like two and a half thousand of those people, and they had something like 87% of them were maintaining at least 10% of that weight loss after both the five-year and the 10-year mark. But they also found that that larger initial weight loss was associated with the higher probability of long-term weight loss maintenance. And that's something that you do see in other shorter-term trials as well, that faster initial weight loss, particularly in groups of people with obesity, tends to correlate with it, that they don't essentially regain all that weight back because it was more difficult of a dieting period, or they had to go more rapid. I think a common myth is that you'll definitely gain it back because you've been restricting so much. It doesn't seem to play out at least in that, but I think there is some, depending on the study, there probably is some variance in that response too. Yeah, I think, well, that Australian trial that I mentioned, that was in whether participants were in the gradual or rapid group, they just all started regaining weight and they all regained the majority of it. But it's not necessarily always seen. There was an Arne Astrup study way back in the 90s, which looked at a rapid weight loss intervention using a very low calorie diet. And then after the intervention, so everyone lost weight, kind of really quickly in this intervention, and then after the intervention, they were then randomized to either a kind of ongoing low fat high carbohydrate, high fiber diet, or just a fixed energy restricted diet. And they did have intervention intensive patients follow up and follow up support. And at two years follow up the fixed energy. So they lost 13.6 kilos, give or take in both all participants, then they're randomized to either this kind of high fiber high carbohydrate low fat diet, or just an energy restricted diet. And by two years follow up, the energy restricted diet had regained 11 kilos, and the ad-liberative low fat high carbohydrate high fiber diet had regained only 5.4. So this again speaks to the importance of being really clear about what we're talking about absolute terms, what's the magnitude of weight loss relative to regain. And while it indicated that the kind of initial rate of rate loss didn't really have an influence on maintenance at two years, what actually influence maintenance at two years was the dietary modification plus the behavioral cancelling again. So, you know, again, we're back to behavioral correlates of maintenance versus regain. I wrote an article years ago, and at this point on some of the rapid weight loss in different interventions. But there's one there that I remember was the, I think, knackers was the lead author of the knackers, and within that trial, they didn't set out to have people have different rates of weight loss at the start, but like they gave them that six months, and then after that, they stratified into people who had lost the smallest amount, a moderate amount, and then the most, and then it was like maybe five kilos in the slow group, and then 13 or 14 in the fast group, and then another follow-up at the 18-month period, and the weight regain in an absolute amount was pretty much the same as that one or two kilos in all the groups. And so that was one that I tended to point to as, but yeah, this more of this weight loss upfront, at least in this population of people, seemed to, doesn't have this compensatory effect of, oh, you're just going to regain more of that back because there was more initial weight loss, it seems to actually fitting quite nicely with maintaining long-term. And also, even though at this point, it's only two years of follow-up, there obviously will be more, but Roy Taylor's interventions have, and they've looked specifically at responders versus non-responders. Now that's not, I should highlight in the context of weight loss, it's in the context of beta cell kind of restoration of beta cell function, but it has important implications for magnitude of weight loss and regain. And again, they use a VLCD three months on average, but they also have a structured reintroduction phase followed by a structured maintenance phase. So I think, again, we're coming back to the idea that you have behavioral support in the post-intervention period, but you actually have a plan. I think probably is a stain on a lot of the previous interventions, it's just right, the interventions over. We'll contact you in two years to see how you've done, but there was no actual idea that, in fact, whatever about the intervention, anything can work. I think most people in nutrition that aren't married to any dietary belief would probably accept now that any number of interventions, dietary wise, can work, high carb, low carb, whatever, low fat, high fat, it doesn't matter. What matters is the, you know, the post-intervention phase and the behavioral correlates of it seems getting someone at least over a two-year hump at which their chances of long-term protect, you know, avoidance of total regain exponentially increase. So I think that's kind of quite the important factor. And there does, yeah, there does seem to be a degree of support that rapid and more rapid initial loss can have better correlates with outcomes. And that's because it seems that although a degree of weight will be regained, it will still only be perhaps, you know, a third of that which was lost, giving someone still a significant net gain overall that may have an important kind of bearing on disease risk reduction. With that, if we start talking about some of those influences, which to some degree we already have, but just when we're talking about weight loss maintenance, given the, at the outset, you talked about those different aspects we need to be aware of when it comes to duration, the amount of the right weight regain, what we would classify as success et cetera. Just to be really clear for people, what should we clarify as what weight loss maintenance is? Do you tend to favor, because I know there's, there's different rates that tend to be put out there. Yeah, I mean, I tend to favor the, if we're, again, putting numbers on it, I tend to favor the idea that actual true maintenance is, you know, maintenance at say, for example, four to five year mark post intervention. Because I think that's really telling us, because we know that, you know, certainly from the look ahead trial that there appears to be a stabilizing effect beyond that point. So that appears to be, while going beyond two years exponentially increases chances of maintenance, it doesn't necessarily, that increase gets stronger still over time. So in my head, I've kind of settled on five years as a timeframe that I think is most representative that if someone gets to that point, then the likelihood that that's a kind of a long term, you know, kind of baseline stable weight is quite high. And then in terms of magnitude, I would in this context think that maintaining between five to 10% is successful if we want to use that word for it. So yeah, five to 10% maintained at five years. I think for me would be a kind of set of characteristics that I would be happy to deem that intervention successful and in terms of maintenance. Just a touch on diet composition. I don't think there's a whole lot to be said and that won't be a surprise on base we've just discussed. Some of those associations with things like greater vegetable intake, whole grain intake, dietary patterns that look like the dash diet, so fruits, vegetables, etc. There's at least something that they tend to correlate with weight loss maintenance. But apart from that, there's nothing particular that I think is distinct here for weight loss maintenance that wouldn't be the part of any type of healthy dietary pattern where you're trying to control energy in general anyway. Yeah, exactly. I think once you've got those general hallmark characteristics of adequate to maybe higher dietary protein and high fiber intake, I don't really see that the rest matter all that much in terms of ratio of carbohydrate to fat in the diet or with those kind of variables. Yeah, because I mean, all you're trying to do from this perspective is is what way can this person eat to control energy intake in a way that they can sustain. So yeah, getting sufficient fiber, protein, maybe including low calorie density foods can be useful there, but apart from that, there's nothing too much I think we need to linger on. Probably where there is very strong and compelling evidence is around physical activity and perhaps where it's the most consistent and clear association where you see that higher levels of physical activity increasing that probability of successful weight loss maintenance and in those that have the lower levels or I think particularly if they see a decrease in their physical activity over time, that seems to be quite predictive of that weight regain we mentioned earlier. Right. Yeah, physical activity is probably, I think it's the most consistent behavioral factor that predicts maintenance and correlates with this idea that we've been talking about a time spent in maintenance. Being a really important determinant, what appears to facilitate that that time spent in maintenance is higher levels of physical activity and I think the you know, the kind of contrast with low levels of physical activity is actually quite stark in that sense. Some people have tried to argue that the reason high physical activity is effective is because it improves cardio respiratory fitness and actually that is something that we should focus on and we shouldn't necessarily focus on weight or out of capacity and there's some degree of merit in that, but the caveat I always say is those those studies tend to not be in participants would say BMI of over like 35 and so you know, there does certainly appear to be an area kind of area of BMI certainly if we're just using that metrics, which I know is not necessarily great for for individual level risk and doesn't you know factor in things like lean to fat mass and out of post tissue distribution, but in that context physical activity and cardio respiratory fitness are important, but I think there's probably a point at which if there is a reduction in out of capacity warranted for improving health, that physical activity is not necessarily going to just be having an increase in cardio respiratory fitness immediately because that's something that takes time to build. So yeah, I think I think physical activity just generally is a behavior like cardio respiratory fitness is an outcome, so I think it's you know, because I've seen some research that really up plays cardio respiratory fitness down plays excess out of capacity, I was like well actually cardio respiratory fitness here is an outcome physical activity remains the behavior, so that's that's again what we want to focus on. Maybe the misconception is that high physical activity is simply there to contribute energy expenditure. Of course, it does do that and that is part of this issue, but if we're also trying to control caloric intake, I think the group out of leads Mark Hopkins has actually been on the podcast before and I think they've probably done the best work in this area of showing at those low levels of physical activity, once someone becomes completely sedentary, they basically have this inability to properly regulate appetite and therefore their caloric intake. And I think that's probably at least part of the issue here that if you can keep high physical activity, it may allow better regulation of energy intake as well as opposed to just contributing energy expenditure. Right, exactly. Yeah. One of the areas that actually I think is going to be where there might be some controversy and actually relates to the whole discussion we have to start around, so it's the dichotomy between non-dying approaches and the kind of fitness industry model would be around self-monitoring because particularly in relation to self-monitoring of food intake and self-monitoring of body weight, they seem to be again quite consistently in support of a benefit in terms of long-term weight maintenance, but this is probably clearly an issue where we need to dig into some of the nuance and context, especially on an individual level of what we're trying to do, while acknowledging that in a large majority of the research, we do see a positive association. Right. Frequency of self- weighing in particular is really positively associated with maintenance. It's also controversial now. One of the nuances that I found interesting is that one of the arguments is that we'll self- weighing, we'll have a negative impact on psychological well-being, and we know that poor self-esteem associates with weight controlling behaviors overall, but that is kind of instructive in itself. So one of the things in terms of other psychological predictors is higher self-motivation and also self-efficacy and internal locus of control, and so when I look at that self- the self-weighing thing and if it is a risk or not, what speculative assumption that could be made is that in people with those characteristics of greater self-esteem, self-efficacy, internal locus of control, it has a positive effect and potentially would have a negative effect in people who have low self-esteem. But again, this comes back to the idea of screening because I would argue based on some of the other research that these behaviors could likely be present prior to an intervention, but the idea that it is ubiquitously negative behavior with negative consequences is just not the case. We know that there are regular self-monitoring of weight, it can be evident in terms of maintenance for up to a decade. So it's a potentially problematic behavior for some individuals if the appropriate level of screening is not undertaken prior to an intervention. Yeah, and I think the important thing for practice here is to remember that even when we're talking at this being correlated with a benefit for long-term weight loss maintenance, remembering what is defined as like success as opposed in those studies is does this person remain a certain weight, not necessarily are they psychologically healthy and happy and so on. And I think again from practice, most practitioners will have tons of experience with people who are not going to respond well to either weighing themselves regularly or even at all, or even monitoring food intake in some of the typical ways that is done. And like you say, a screening process for that in practice to make sure we're not trying to fit everyone to the same mold where it's going to be maladaptive and problematic is important. Like really in the long term, what we want is people having clear behaviors with less and less tracking and maybe being able to cultivate that internal locus of control without needing an external parameter like a body weight measure that they can still feel in control and still feel this self-efficacy without the need to back that up with an objective piece of data, they can do some more on some of their internal cues. Right. And this is part of the difficulty navigating the kind of I guess battle between the just general fitness industry model versus non-diet approaches is we can be seen and I'm sure I may be sound right now like I'm completely discounting risk and I really want to emphasize I'm absolutely not. I'm trying to emphasize that there is risk to dietary interventions and that they need to be appropriately factored into any assessment. I think that's the important kind of point to try and hammer home. I'm not just assuming that this is a benign intervention and will you know, frequency of self- weighing is going to be fine in all people. It comes back to appropriate screening. What I'm not going to do, which is the other side of the fence, is assume that this evidence just isn't there because it is. So I think it's just about trying to bring this dialogue back to some place of objectivity which has been a real challenge because factors like weight stigma and that the really maladaptive and debilitating effect that that has on people as an individual level and societies. I'm not questioning any of that but I don't think it's helpful either to as a lot of this conversation has got to a place of almost denialism about weight science because I think there's a lot to be said for okay we can acknowledge that this finding is here we can now just look at why could why is that potentially the case and then you have lots of interesting questions explores to what might explain that. So I do agree with that and then on a again a practical side for practitioners it's I think there's a way of having a discussion about what a body weight measurement means that can kind of at least mitigate some downsides that it's just a proxy measure for something else and there's no inherent value that needs to be placed in that and it can be completely divorced from any self-worth and identity. Now again saying that to someone is one thing someone believing that is a different so it may be completely contraindicated for many people I completely get that and that's why not everyone should do it but there's also a way you can frame it as being able to disassociate this being anything that reflects any value or is anything other than a proxy for something else like like the actual body weight doesn't matter in nearly every case apart from if you're a weight class-based athlete then it matters for three days of the year. So maybe let's just round off and like everything we've said and tie that into some like practical takeaways if we can. What are some of the main things that when you look at this area of research are most clear to you and are the things you would tend to pass on to people? Well the first thing is I think taking the whole area as a whole yeah there's no denying that there is an overall kind of lack of very quality robust evidence for long-term maintenance but that seems to relate to the level of behavior change and intervention that's required to sustain that. It doesn't mean that there's no evidence and there is. Within that evidence what is really clear is that the factors that tend to positively associate with maintenance are intensity of the intervention in particular a total number of by intensity I mean total number of actual practitioner contacts with a healthcare professional with a multimodal approach being preferable. So total contacts and frequency of contacts the rate of initial weight loss may be a factor that improves outcomes although that's not necessarily entirely consistent. The shifting of increasing numbers of behaviors and physical activity self-wing when it's when it's not maladaptive and dietary modification appears to really kind of fall like a distance I wouldn't even say distant third but distant factor behind all of these correlates. We do also know on the flip side that weight regain may be predicted by higher levels of maladaptive behaviors at baseline so indicating that participants may also be struggling with restrained eshing or disinhibited eshing low self-esteem poor body image and low kind of self-efficacy internal locus of control and so those factors are really important because you know where like it's not I don't think ethical of us to put people that you know score on any of those measures into a weight loss intervention but that's really what the research community's been doing for 30 years. So the point is that there does it while the actual psychological predictors of weight loss are not all entirely consistent there does appear to be a delionation in terms of some of the factors that predict weight regain and some of the factors that predict success and in addition to those behavioral correlates of successful maintenance that I just mentioned the two factors that I think are really important are duration spent in maintenance and you know the frequency of practitioner contacts both of which relate to each other and for that time period I think really the two to five year mark post intervention is is probably most kind of instructive in terms of where maintenance seems to stabilize. I would also echo the need to on an individual level consider is a weight loss intervention a good idea for this given individual or not and I think a lot of people could benefit from having that as a screening question early on. Secondly like you said if there is signs of some of those psychological issues which may undermine their potential success in the future with weight loss maintenance that could be a good place for a referral to a professional within psychology and then I would say in terms of long term weight loss maintenance where that is desired and where someone is going to go with that realizing that weight maintenance is actually a range of weights that you're going to fluctuate between as opposed to you hit 75 kilos and stay at 75 kilos it's probably a number of of kilos and there's different ranges here I've I think I cited like a 3% range but there's others that would be like 5% but having some sort of range that is normal on any given week month or long term where weight can stay within and we're still going to include that as weight maintenance so those be a few things I would say and then maybe finally from a practical perspective at least anecdotally it seems that it's beneficial to have a gradual move from a weight loss intervention into long term weight loss maintenance and that kind of mitigates the problems that you highlighted earlier when someone finishes a weight loss intervention and now just go off and do whatever you want to do tends to be problematic whereas not only having a plan for a weight loss maintenance specific period of time but there's even some of the review papers talked about cases where even people were counseled a couple of times about long term weight loss maintenance they had better outcomes than if they had been told nothing so they weren't even given follow-up support they were just did one-off session at the end of their weight loss intervention they still had better long term weight loss maintenance outcome so I think all of that ramble hopefully makes some degree of sense but I don't know if there's much else I would say on that I don't think so cool well and it's time to move on and let's get to our listener question of the week so our question this week I don't have the name I don't know how I managed to lose that so apologies whoever question this is I don't know if you're name but good question regardless so the question is how does the apoE4 allele affect lipid metabolism and how should someone structure their diet around having one or both alleles due to resulting in higher LDL cholesterol than someone without the gene and so maybe and can you can you give us like a pregarser to what apoE4 is for people who haven't heard that term yeah so apolipoprotein e or apoE is a gene that makes proteins that carry cholesterol and fats in the blood there are a couple of alleles that are generally of interest when when we're talking about this and disease risk in particular cardiovascular disease and Alzheimer's and there's apoE2 which is pretty rare although if it exists it is generally considered protective there's apoE3 which is the most common boss it is relatively neutral in terms of associations with with disease or with impacts on blood lipids and then there's apoE4 which is generally associated with an increased risk of cvd and Alzheimer's and you can have one or two apoE4 alleles having one is the most common so that's in maybe 25% of the population having two is only in about two to three percent of the population and the general association is due to the impact of apoE4 on blood cholesterol levels and generally we're talking about increased LDL cholesterol in particular and the people who there's evidence the people who carry that apoE4 allele will be more responsive to reductions in dietary saturated fat than people with say the apoE2 or apoE3 so they'll actually have quite pronounced reductions in blood LDL cholesterol levels if they reduce their dietary saturated fat intake and that's that's generally the kind of where the advice falls from a dietary perspective. Do you think it's a case where if someone does have one of those alleles they need to be more careful on average of higher saturated fat intakes or does that change from typical guidelines at all in any way is there any way they may respond more negatively to a higher total fat diet regardless of the source or do they need to do anything it's particular. So there is some evidence that total fat as well can have a bearing and I think generally the advice is for lower total fat diets but in particular because we know that the pronounced effect on blood cholesterol and LDL cholesterol will be driven by saturated fat specifically that reduction and and in general although I think if we're relating this to public health guidelines of like the 10 percent threshold certainly if I had the apoE4 allele I that wouldn't be my target necessarily I'd be trying to be even even lower with that and and probably going full Mediterranean and and kind of 5 to 6 percent of intake so I do think there is merit to trying to get that particular fat substrate low and I do think that there is probably also merit in having a lower total fat diet increasing dietary fiber and these kind of factors that can actually modulate blood lipid levels. Okay I think that answers that question at least so hopefully that was a satisfactory and that brings us nicely along to our wonderful quack asylum segment. Yeah. The quack asylum. So this is interesting right this is a because not only about the claims that we're going to discuss in a moment I think this broadly actually talks to a bigger issue about people that may have expertise in specific areas and maybe medical doctors which carries in some respects deservedly some degree of reputation and credibility but can then sometimes lead to them being given more room with claims about nutrition science and I think as you've been at pains to show in the past there are some distinctly unique things about nutrition science that need to be understood that said there are many doctors who do a fantastic job about educating themselves in around nutrition science and I want to acknowledge those people however this these claims are even more egregious in that it's not just a lack of understanding around nutritional science it's like just almost making things up that have no basis so it's it's it's also egregious insofar as it's it's one medical doctor making claims but the other not even being in any way kind of inquisitive or skeptical in a in a constructive way about those claims. Yes and that's a unique problem because for any so maybe I'll just introduce for so people can kind of clarify I was sent on a podcast episode from a podcast I was not familiar with before this past week where a medical doctor I believe she's a GP here in Ireland has a podcast and was talking to an endocrinologist also based here in Ireland on the podcast and about halfway through they start talking about some nutrition advice now I think the podcast episode was about women's health more generally and about hormones but this particular point that I was directed to was presumably in relation to that but what dietary modifications would be recommended and so as you said it's particularly problematic when you have not only a medical doctor saying these things but when it's also to a medical doctor that can give people listening more confidence that this must be correct because there isn't pushback on it so there's there's probably four things I'm going to highlight here there are a couple other things that were quite strange as well the first one was the first claim that that peaked my my interest was the claim that sugar is toxic now I didn't actually get all that to work up about this because this is something that I think is quite pervasive within the mainstream population it's not like sugar is an inherently nutritious food that where we should be promoting more of and it could just be a bit hyperbolic right telling people don't have a lot of sugar on the flip side it is problematic I think to start using language like that that is not technically accurate particularly coming from a doctor and there can be again psychological impacts of telling people certain foods are toxic and so on and leading to I think the recommendation was don't have any more than two treats per week whatever that means but I could almost let that one go and we can revisit the sugar as toxic if you wish but one that I think you'd be even more interested in and this is it was about like 20 minutes into the conversation they brought up the issue of eating frequency and the claim made by this doctor Dr Ryan I think it was she said due to circadian rhythm in the bowel you need to eat little and often I am unaware of any evidence or any even mechanistic reason why eating little meals more often throughout the day does anything for digestion or that the bowel requires one to do so yeah so there is a circadian rhythm in gastrointestinal motility that speaks to nothing more than we have a fairly well established kind of diurnal variant so time of day variance meaning that there is better gut functionality during our biological daytime and active period than there is during the biological night and that relates to nutrient digestion and assimilation but that's very much as between time of day comparing our kind of waking and active phase which in humans is our food intake phase versus the nocturnal period the idea that that somehow translates to a need for a little and often or a higher meal frequency I don't know where that was invented dreamed up of or otherwise yeah it's a fairly it's a fairly outlandish claim and I think you know again it's interesting because even if we just remove the chronological or chronobiological claim for one second you know it's one of the more well established aspects of nutrition at this point is that meal frequency per se makes fairly little difference in terms of metabolism or otherwise so that alone was was was sufficient you like misinformation but then it's added on to sprinkled onto by this suggestion that it's your circadian rhythms that yeah and and this was the problem that when you sprinkle in language like that almost lend some credibility to her and I think she followed up the comment with about yeah it's it's down to physiology and again when you're talking to a broad audience of people that there's so much that could be done to change people's dietary patterns overall now you're having people worrying about something that they don't need to and can actually undermine some of the things that they could have been doing really well otherwise and so on the little and often metabolism issue it continues that the interviewer follows up asking about that eating often thing and so the guest doctor Ryan then says quote as women we have a slow metabolism so we have to trigger it and then presumably by eating more of these meals more often which again this idea that you need to eat often to stoke up your metabolism or keep the engine running or that if you eat less meals throughout the day that means you have a worse metabolism is just complete complete nonsense yeah yeah and that like you know those sex differences in RMR if we if we assume for one second that there's some some credibility in the claim which there's not sex differences in RMR are generally know once you adjust for that they're explained by differences in lean mass to fat mass and that applies even to people of different body sizes for example so there are age related declines in RMR but there actually isn't really much good evidence for biological sex differences in RMR once you account for differences in in lean mass to fat mass and body size and then the implication that even if there was that you would boost up your metabolism with these little meals that just not correct yeah the final one we all we all end on and not get too much more into is I found this really useful I don't the exact quote but it's the kind of paraphrase they were talking about like what should be included in different meals and she made the claim that basically Monday to Friday don't eat root vegetables because they store too much sugar so keep them for the weekend and like stick to green vegetables for your dinner during week and then a root vegetable is like a I suppose a weekend train so yeah so and and this was the one for me that's like like this is kind of really problematic because you could have people are really trying to improve their health and have maybe made some really positive changes and have done lots of things right and have tried to include more vegetables and now they're being told that they're making a mistake by having carrots during the week at their dinner it's it's absurd and it's it's it's so problematic yeah and that was the one that like that really annoyed me don't eat slaughter not squash yeah these food these yeah don't eat your sweet potato these these foods have a negative influence on your like yeah it sounds like I'm so happy I haven't listened to it I did a friend did say to me yesterday that she had been sent us and listened to it and she made a really interesting point where you know she said the idea that this like female specific focus means that like you know it's like oh well women empowering other women she's like it's actually completely disempowering to be filling people you know this idea that it's oh it's what's women specific and we have differences in RMR we circadian rhythms in bowel don't eat carrots it's just like there's nothing more disempowering well to anyone but specifically if this is the kind of inference that they were going for that's then then misinformation right and it's it goes against nearly some of the important things we've discussed early in this episode of like focusing on helpful behaviors over over the long term and then but then also paying attention to some of those like psychological aspects around food are a food relationship and now you're telling people who are already probably health conscious the fact they're listening to a health podcast right now to be worried about root vegetables right yeah it is so problematic it's absurd yeah Mary Ryan you're in the crack asylum consigned consigned at least from a nutritional perspective but yeah that those claims alone are yeah and I mean that's that's the thing that got me like if your medical doctors your recommendations need to be evidence-based right not a single thing that was said there on diet was evidence-based yeah and that's problematic I just don't know why it's I would think that in most health care professions like we understand scope of practice but and I don't want to you know slight the profession as a whole but it is a Barney I've been in for multiple you know multiple kind of a few years and through through a few channels is yeah there was even a study recently that looked at it's like a quackery and advocacy in and it looked at nutrition books populist nutrition books with crazy claims and then looked at the stratified the books by the profession of the author and 35% were written by MDs you know but that's and that was disparate that was by orders of magnitude higher than than any other category of of health care professional and so you know this is a problem that is kind of a bit endemic in the UK in Ireland in the US this assumption and it carries huge authority bias and it's it's just veering so far out of lane and scope of practice this assumption of kind of a general ubiquitous knowledge to apply to a subject and I find it personally really frustrating because there's just a higher standard and duty of care on on on medical professionals and in terms of being evidence based and not miss informing the public about stuff they don't know anything about yeah and it's like it's such an easy issue to avoid like you can't tell me as a medical doctor you cannot pick up the phone and call a friend who is a registered dietician yeah like I just say okay as a dietician are these things that I believe true right or here's here's what I tell people do you think this is like you can get a dietician to look over that in a second and see that every single one of those things is nonsense or at least they they should I hope so if they're an evidence based dietician yeah and maybe that's a discussion for a different day but in general at least that is a step in the right way where yeah yeah it's just it's it's inexcusable that's the whole thing like it's it's not there isn't an excuse to go on a platform like that and just put out nonsense when it carries the waste that people will believe us yeah so I think that's a useful example this week so there we go let's let's let's finish up here let's get to our random recommendations something random as anyone that hasn't had their head in the sand for the last kind of year and six months will note you know that there's a huge scrutiny now on and a lot of various social justice issues and I'm what emerges you know if anyone listening ever did English and did postmodernism is is this a very particular school of thought that is driving the conversation and there isn't a huge amount of of critical insight and analysis into whether that school of thought is useful or correct or even potentially having a harmful effect and the few people that are doing that critical analysis are Helen Pluckrose and James Lindsay and they've just released a book called cynical theories and and I also which is something that I think is going to be really useful and there's also an excellent if anyone wants a kind of introduction to this Helen Pluckrose gives a really eloquent lecture on YouTube on the evolution of postmodern thought and and kind of critical social justice theory and and it's something that I'm trying to recommend to more people now because I think we need to start being aware that this isn't just the the the school of thought through which we think about these issues is going to be hugely important there's that quote about you know whenever there's a crisis the the change that happens is a reflection of the ideas that are lying around of paraphrase that and I think it's really important that we're sure that these ideas are the right ideas we want and these two academics are possibly one of the few people offering any kind of critical appraisal of whether that school of thought is so I'm I'm trying to recommend their recently published book and certainly Helen Pluckrose is excellent YouTube lectures and to more people perfect and those will be linked in the show notes so I definitely recommend people check that out and I echo what you say not only about this issue broadly and the need for critical thinking which is I think as we've mentioned actually before in the podcast is sadly lacking at the moment and actually listeners of this podcast that have been around a while you may have remembered about I guess 18 months ago James Lindsay was on the podcast talking about some of the origins of some of this which is now even exploded in this in the time intervening and so if you enjoyed that discussion then definitely check out both that lecture and the book that Alan has recommended that will be up in the show notes and I'll also link to James's appearance on the podcast there too. For my recommendation I'm going to go with a podcast episode that I think I might have posted out in the newsletter this week as well it was on Lex Friedman's podcast so that's F-R-I-D-M-A-N he's a researcher he wasn't MIT I think he's now left he's in the area of artificial intelligence but he's a pretty cool podcast and he did an episode with Sheldon Solomon who is basically a social psychologist kind of interesting guy. He's amazing. Yeah and the episode they did is called Death and Meaning it's like three hours long and it's amazing and there's just so many different concepts they get into they get into the whole issue around death and how that relates to the whole worm at the core theory that Solomon has they get into existential risk and all the ways civilization could collapse they get into disagreements he has with Jordan Peterson like all these different issues that are really fascinating and he just thinks about things in a very deep and interesting way I just recommend people if they have time to go and check some of that out or at least go to YouTube and and check out some of the clips you can find smaller clips of that but that would be my recommendation. I think he's excellent some of his research is absolutely fascinating there is a link to a Sheldon Solomon lecture that you can add to the show notes that I think is particularly sums him up on his research perfectly but his turns of phrase in it like just listening to him articulate like the problems with humanity you're just like oh god yeah tell us how it really is and I think that that does us that is it that is our episode thank you so much for listening in I really hope you enjoy it hope you took something from it if you did please please consider sharing this around the internet or telling other people about it the show notes are going to be over at sigmanutrition.com/episode352 you can go and check out any links relevant to this episode there you can find me either on Instagram Danny that an underscore sigma or on Twitter nutrition Danny and you can find Alan on Instagram as well at the nutritional underscore advocate and so if you're going to post please tag us let us know that you enjoyed it and we look forward to hearing your feedback about this particular episode that is it I hope you join me for the next episode of the podcast make sure you hit subscribe on your podcast app and then until then have a great week stay safe and take care