Portion size: How much should you eat?

Hello and welcome to the Food Chain from the BBC World Service. I'm Ruth Alexander and this week we're focusing on portion size, how much we put on our plate, how much we should put on our plate and why it's so difficult to get it right. I'm in my kitchen because we're going to start by comparing portion sizes here in the UK with those in the United States and joining me from New York is my colleague Natalie Jimenez. Natalie, hello, thanks so much for being with us today. Thanks for having me. Now, we have both been a hard at work ordering ourselves takeout for lunch, haven't we? And from the same fast food company, large chicken nuggets and fries. And I'm very interested to know how many nuggets you've got. I got 20. I got double, so I got 40. A little bit heavier than yours. Yeah, well, I hope you're hungry. Fries, I have been measuring these or weighed them. And I have to be very precise 157 grams worth of fries. So I have almost or up to 90 individual fries in this one packet and it weighs about the same as yours. It's 150 range. Okay, so fries are about the same. Well, I popped to the local shop to get myself a drink, soda, 500 millilitres. That's the kind of standard size bottle you would find for a fizzy drink in the UK. So as you can see, mine's much bigger. It's double. It's 800 millilitres. So it's almost a liter. But this is for one person. It's not the biggest size. I actually got the smallest of the largest. So I can go up one more and that'll be a super size. So it's almost the size of my head. Wow. So I hope you're thirsty. Now I'm treating myself this lunchtime. I know it's not the healthiest, but I have ordered myself some chocolate cake. And I've put this on the weighing scales as well. And it was 135 grams. How about you? I've also ordered chocolate cake. Mine is the extra large size. It's 195. So a bit bigger. It's kind of like the big brother of yours. Yeah, well, I thought this was big, but that's huge. Well, okay, Natalie, you've done well there. Bon appétit. Cheers. How much is on your plate or in your cup can actually tell you a lot about the culture you're in and the commercial interests at play there. I've been talking about this with two registered dietitian nutritionists, Dr Lisa Young from New York University, author of the book The Portion Teller, and Dr Marley Alvarenga from the University of Sao Paulo in Brazil, who's an expert in eating behavior. I began by asking Lisa why portion sizes in the US are often so big. So the fascinating thing is that portion sizes began to increase in the 1980s. And what was happening was, first of all, there was a lot more eating out. And so it was that led to competition. If one company, you know, a pasta place would sell a small dish of pasta and then another one would have a bigger size, people would want to go to the one with a bigger size. So that was part of it. Food was also very, very cheap. And when food is cheap, it's a win-win for the manufacturer to give you twice as much and charge you an extra quarter. You think it's a consumer that you're getting a bargain, and they make more money, the food industry. So it ended up being what appeared to be a win-win. The other thing that started happening, and what I started looking into is when places like McDonald's and 7-Eleven started offering these jumbo sodas, they were studying the psychology of eating. And what would happen was no one is going to buy two or three 16-ounce sodas, because they'll feel like they ate too much or they drank too much. But if you take one size, and you make it super size, and you sell, you know, a 32, 42, 64-ounce soda, even though it's a half gallon of soda, it's only one. A 16-ounce soda, that's about 450 milliliters. 32 ounces is twice that. 64 ounces is four times the size, almost two litres. Yes, exactly. So the consumer pays an extra quarter for twice as much, but they don't feel that they ate too much or drank too much, because it's still only one. Does that make sense? It does, yes. Marley, you've compared US portion sizes to those in Brazil. What did you find? We decided to compare this with Brazil to have an idea about a developing country, to see how it behaves. And we found that Brazil, as other places, is mirroring US trends. But actually, when you look at this data, we see that it happens mostly with packages and processed foods. We have also bigger bottles of soda. We have a station of serving sizes in fast food restaurants. We have big bottles or balls of popcorn in the move theaters, mirroring American patterns. You don't see in here bigger portions of rice and beans or fish and manioc flour. That is our traditional foods in now, day by day, or in traditional restaurants. What you can see that it became bigger and bigger is the food that we import from US mostly. The same brands you can mention in US or in other parts of the world are be selling here in the same way. And what about in France? There's a very interesting study made by Paul Rosen measuring foods that are the same in US and France. The same brand of yogurt, the same brand of fast food sandwich. And they found that in France, everything was smaller. Even soap, even toothpaste in France was smaller also. Actually, what we know about France is that they have a very, very traditional way to eat. It's not just related to what they eat. They are the people that spend more time at the table in the world than probably this have something related to. Lisa. I just want to chime in because like what Marley was saying, a lot of it is the Americanization of the food system. And as these American-type foods like a McDonald's or certain candy bars move over to other countries, those sizes start to get bigger. But they're never as big as the American size. The mentality of Americans is we value bigger houses, bigger sizes, bigger portions, as opposed to the French and other countries that are really more focused on the quality of the food and the eating experience. Whereas we wolf it down. We don't pay attention to our company. We pay attention to, wow, I got a big portion. We value the bargain probably more than any Western country out there. It's about the bargain. Lisa. So what you're both saying then is that portion sizes are influenced by not just commercial interests, but also cultural factors. Yeah, absolutely. Yes, absolutely. And Marley also raised another point that I want to elaborate on because you didn't use those exact words, but it's the ultra-processed foods. You had mentioned it's more those processed foods. And what's happening is we're now in our field in the dietary guidelines that hopefully will be coming out soon. There's a big discussion about a lot of the problem with big portions is in ultra-processed foods. It's not going to be in apples, and lettuce, and rice, and beans. It's these man-made foods, the fast foods, the candy bars, the soda, high in sugar, salt. And I had done a paper in 2021 where I talked about the change just from its original size to 15 years ago to now of ultra-processed foods specifically, hamburger buns, the french fries, the sodas, the candy bars. And these are foods that Americans and other people tend to eat more of without realizing it. And you eat an extra 500 calories they found when you're eating the ultra-processed foods. So it's particularly problematic because you're not eating a bigger portion of a home-cooked meal, whether it's rice and beans or whatever, but it's the ultra-processed foods that are made by somebody else that have all sorts of ingredients and processing in it. Yeah. Lisa Young in New York and Molly Ulvarenga in Sao Paulo will hear more from them later. Now, does being presented with a large portion of any food automatically mean you'll eat more of it? I asked Professor Lenny Vartanian from the University of New South Wales in Sydney, Australia, who's an expert in the psychology of eating and weight. So one of the most robust findings that we have in the literature is that people will eat more when they are served larger portions than when they're served smaller portions. And it's not just a matter of them eating everything on their plate because oftentimes people don't finish everything, but we know as the portion size increases, so too does the amount overall that people end up eating. Do you know how much more people tend to eat? So there was one meta-analysis, which is a summary of the existing literature, that estimated that when you double a portion size, that people will eat 35% more. That's more than a third more than you would otherwise. Yeah. And why is that? Well, I think it starts with the premise that it's really hard to know how much is the right amount to eat. Sure, we think that we should be able to rely on our guts to tell us when we're hungry, when we're full, but our guts aren't that reliable. So we find ourselves in many situations being a bit uncertain about how much we should eat, and portion size, like other external cues, can give us a guide to help us determine how much we should be eating. That's so interesting because you think, well, if you're hungry, just eat and then stop when you're no longer hungry, but it's just not that simple then. In this day and age, we don't often find ourselves in situations in which we're feeling especially hungry or especially full. We're usually in that zone somewhere in between, and it's in that zone somewhere in between where we can be pushed around by all sorts of different cues. The amount of food that's put in front of you will probably be kind of the strongest signal to you about how much you should eat. You look at that and think, well, okay, all of that. Yeah, presumably when we're in a restaurant, or even if you're buying food that's been packaged in a shop, there's somebody along the way who has made a determination that this is the right amount for you to eat. And presumably that's somebody who knows what they're doing because they work in the industry. So it gives us an idea that, well, this must be an appropriate amount to eat. So when we're served a portion in a restaurant, especially if we've paid for it, we're probably going to eat most or all of what we've been served. So we're more likely to trust somebody else's judgment about how much we ourselves should eat. I think the food environment in general is really complicated for people to understand. For a lay person to understand calories and macronutrients and amounts of different things that they need, it's really challenging. So we often do rely on other sources to tell us what we should be eating and how much. If we were left to our own devices, I don't think most of us would be eating five serves of vegetables a day, but somebody has told us that that's appropriate for us. That's what we really need. And so we try to do that, not very successfully, but we try. So we often are relying on other people to give us some indication of what or how much we should be eating. And portion size really isn't all that much different, I think. How much attention do we pay to portion size recommendations on the side of packets? The suggested servings on the side of packets are very confusing. And I think that many people will not be making much use of them because they really don't know what to make of them. A standard serve is what's usually indicated, but that doesn't mean that that's the only thing that you should be eating. Sometimes eating more than one standard serve is okay. So it really depends on the context of the meal. So overall, I think people just have a hard time understanding that information and knowing what to do with it. And that makes it very difficult for them to use. Does all this mean that portion size is a key factor in overeating? So portion size can certainly contribute to overeating at a particular meal, overeating with larger portions. So if they eat a large portion at lunch, let's say, they won't eat less at their next meal. And if you serve them a large portion at their next meal, then they've eaten more twice in a row, and then they don't compensate for that at the next meal. So there's no process of compensating for the overeating. And oftentimes, when people discuss portion size, they talk about it as being one of the key factors that's contributed to weight gain and obesity over the last several decades. I don't doubt that that's possible, but I don't think the evidence is quite there yet for us to be able to say definitively that portion size has contributed to weight gain and obesity. So if somebody is worried that they are overeating, what advice would you have for them about how to approach large portions? I think it's difficult to put the onus on the consumer because they're often going to be unaware that a particular portion is bigger than what they need. If we're creating an environment in which it's really difficult for people to understand what their needs are, to make sense of the information, and to make those decisions, how can we put the blame on their shoulders? We have to do better to provide them with the mechanisms to be able to manage things better, both in terms of the information that we provide, providing in a clear way, but also practical strategies that they can use. So if packages were made, I don't know how you would do this with a pizza box, but if they created a pizza box that could then fold in half and make it easy to package up the second half, or a resealable packet of chips so that you can eat half, they're partitioned off, and you somehow can reseal it so that you can store the rest for tomorrow, those kinds of things maybe would be a way that people could actually practically manage those things. If you're at home, are there any quick ways to make sure that you're serving yourself a decent sized portion, not too big, not too small? I mean, could you use smaller plates, for example? The smaller plate thing is an interesting one, because this goes back to some of the early days of the work on portion size when we thought, well, if larger portions means people are eating more than an easy way to fix that is to use smaller plates. There was also an element of the idea there that there was a visual illusion going on, that if you put the same amount of food on a smaller plate, it would look like more and you might feel fuller and therefore be inclined to eat less. The research evidence doesn't support that. The plate size on its own has no impact on people's food intake. What really matters is whether there's extra food available or not. So if you're putting a certain amount of food on a small plate, but then the serving pot is just across the table and you can get more, people will serve themselves more if they're still hungry or if they want it or if it's available. So circumstances at home, and we've been talking about these kinds of strategies for years, that people can serve themselves the amount that they want and then pack the rest away, get it away so that it's not available for you to take seconds. Professor Lenny Vartanian. You're listening to the Food Chain from the BBC World Service. I'm Ruth Alexander and this week we're focusing on portion sizes. We've been hearing how commercial interests and cultural factors have fueled the growth of serving sizes in the US and beyond, how bigger portions often lead us to eat more and why it can be tricky to judge the amount we need. So to help us figure that out, I asked registered dietitian nutritionists, Marlior Varenga in Sao Paulo and Lisa Young in New York, how much food should we actually be putting on our plate? You know, I think that that's a loaded question and it's a difficult question to answer directly because... It's so interesting that you say that because I thought that was quite a simple question, but no. It's actually not, I'll tell you why. So the US Department of Agriculture, we had a pyramid and now we have that plate. Basically a visualization of recommended dietary guidelines that a number of countries have showing which foods to eat more of and which to limit. And we used to have sort of recommended, they used to, they call them, you know, recommended servings, which of course they're recommended for who, a toddler. i.e. we're all different ages, sexes, heights, etc. And I'm going to argue, what else are you eating with that meal? What else did you eat earlier in the day? What about the plate itself? Is it true that the size of the plate will influence how much you put on it? Okay, I think there's two issues going on. If the size of the plate is so tremendous, yes, it's going to have an influence. However, many plates, like what Lenny's talking about, maybe the plate is not going to have an influence. If you were to go, like when you go to a buffet sometimes, they don't want you taking so much food and they give you these tiny little plates. So you end up packing the plate five different times because the plate is so small. So I tend to think, and in work that I've done with clients, if you give someone a nine, 10-ounce inch plate, that is a normal size plate. They will eat less than if you were to give them those big charger plates. They will put more on that plate. But when the plate is so small, and it's this like six or seven ounce appetizer plate, having smaller plates does not work to your advantage because you know that plate is small. So you end up going back and filling up that plate three or four times. I have to say, when I'm at home, I don't weigh the food on my plate. I just kind of go with what I think looks right. Are there any rules of thumb, even rules of fist, a fist-sized portion of broccoli, what we should have on our plate? It's not the huge problem, I think, the problem of the meat in your plate or the broccoli. The problem is what is being served for us in restaurants. If they put a full rate of broccoli and 400 grams of meat, as is usual here in Brazil, it's so difficult to say to a patient, eat less meat and more broccoli. It's so difficult to talk about portions of snacks or sweets, to say, eat three chips. Three chips is the correct portion for you, comparing your nutrition necessities. Who eats three chips of potato? And when you have a package, a huge package of your size, and it's so palatable, it's so delicious and it's so difficult. You've convinced me that this is complicated and there are no easy answers to what I honestly thought was a simple question. But if you could give somebody one piece of portion advice, what would it be? So I would say, instead of the word portion control, where you think you have to control something and really elaborating and talking about what Marley talked about, how it's so important to tune into your hunger, I think the most important thing is you want to become aware of what you're eating. People pay no attention to what's on their plate. So I think we want to use that, the deck of cards or the hand size of meat to say, you don't have to eat one hand's worth of meat necessarily, which will be about 100 grams or three ounces or something. But how many of those palm size hands are on your plate? People don't tune into their hunger. They don't pay attention to if they're full and they pay no attention to the size of that. So I think the most important thing is to get people to sort of go back and say, how big is that piece of meat on my plate? Then they can start cutting back if they need to. Another name that we use in this environment is portion distortion, that these larger servings shift what we think is normal. Then my chip will be pay attention, pay attention. Look to the label, look at the size of these. Try to understand what industry are doing with marketing and everything. In an individual level, pausing, during your meals, pausing, slow down, try to eat consciously. Then in this way, you can practice how to decide how much you truly want to consume, rather to being guided for this all external cues. It's not easy, but it could be practicing, practicing in our day life. What about the food that we don't put on our plate, but we reach for out of packets in between meals? How can we get a better idea about what a healthy portion looks like? Well, one thing that's very easy to do is if you, first of all, have whole foods like an apple or a piece of fruit or something that's not in a package, the amount that you eat doesn't matter so much because it's healthy. It's not an ultra-processed food. We want people to eat more fruits and vegetables. If you're grabbing for something with a label, like as Marley said, take a look at that label and it will tell you for cookies per package or for servings per container, 10 servings per container, and it will give you a standard serving, which is not a recommended serving necessarily, but it's a standard. Take that out of the package. Take a look at what that is and compare that to what you actually eat. Then you could see, like people will say, "I only eat a small bowl of cereal for breakfast," but when you tell people to pour out how much they eat and then compare that to what that standard serving is on a label, they're having three times the amount. Tell people to pour out that standard serving and just look at it. Eyeball it. You don't have to measure it. Eyeball it. Then say, "Hey, how many cups worth am I having on my plate in my bowl?" That helps. We have some studies that try to measure these. If you put even inside of Pringles can, you divide these in portions, you can eat differently. Even if you buy a huge package of cereal and Americans have this habit because sometimes you have huge families and you live far away from supermarkets and sometimes you don't go frequently to supermarkets because it's snowing, you can have in the big box of cereal, small packages inside that could help you to understand what is one portion. Then we need more regulation. If you don't have more regulation and education about, probably you will continue the same way. Bigger and bigger. Marley Alvarenga in Sao Paulo and Lisa Young in New York, thanks to them and also to Professor Lenny Vartanian in Sydney and the BBC's Natalie Jimenez in New York. Do you pay attention to portion sizes? Let us know your thoughts and tips by emailing the food chain at bbc.co.uk. From me and the rest of the team, producers Izzy Greenfield and Alexio Conner and editor Sarah Wadeson. Thanks for listening and join us again next week.