ZOE Science & Nutrition - Does calorie counting improve your health?

Episode Date: January 23, 2024

Each day this week, we’re examining one of the world’s most popular diets. Putting the latest scientific evidence under the microscope, we’ll find out these diets' true impact on your health. Today, we’re talking about the century-old paradigm of weight management — calorie counting. Rooted in the law of thermodynamics, the notion is simple: Consuming fewer calories than expended results in weight loss. While seemingly straightforward, the practical application of calorie counting can prove challenging, with many of us underestimating our calorie intake or finding it difficult to maintain this diet long-term. In this special episode of ZOE Science & Nutrition, Jonathan is joined by Christopher Gardner, Professor of Medicine at Stanford University and the Director of Nutrition Studies at Stanford Prevention Research Center. Together, they explore this diet's complexities, addressing its potential and pitfalls.  If you want to uncover the right foods for your body, head to https://zoe.com/podcast and get 10% off your personalised nutrition program. Top tips for better gut health from ZOE Science and Nutrition — Download our FREE gut guide  Follow ZOE on Instagram Timecodes: 00:00 Introduction 00:42 Pre warning 00:52 Topic Intro 01:20 Why is calorie counting so popular? 02:40 Does it matter what you eat or only about total calorie intake? 04:14 What happens in your body when you eat fewer calories? 07:08 What does the science say now? 08:35 How does your metabolism change when you cut calories? 10:29 Why is the diet still so officially accredited? 11:23 What's the verdict? 12:30 Outro Mentioned in today’s episode:  Energy compensation and metabolic adaptation: "The Biggest Loser" study reinterpreted, from Obesity                                        Have feedback or a topic you'd like us to cover? Let us know here Episode transcripts are available here.

Hello and welcome to Zoe's Science and Nutrition and our special daily series about diets. Each day this week, we're examining one of the world's most popular diets, putting the latest scientific evidence under the microscope. We'll find out these diets' true impact on your health. I'm your host, Jonathan Wolfe, and I'll be joined throughout this series by Professor Christopher Gardner. Hello, Christopher. Good to be here, Jonathan. Christopher is a professor of medicine at Stanford University

and the director of nutrition studies at the prestigious Stanford Prevention Research Center. He's one of the world's leading researchers on how our diet impacts our health. So what's on our plate today, Christopher? In episode five, Jonathan, we're getting out our calculators before we dish up our lunch. A note before we start. This episode discusses calorie counting and food restriction. So if this doesn't feel right for you, please skip to the next episode. So Christopher, while we're getting out our calculators, what diet is this?

Well, mathematically, it's a diet that makes sense. If so much of this has to do with how many calories you eat, you might want to count those calories. So our team has looked at the history of calorie counting and actually it first gained popularity in the States 100 years ago. So this is like a really old concept. Why is calorie counting still so popular today? Oh, it makes a ton of sense. So this is, you know, the law of thermodynamics, calories in, calories out. If you had, especially if this is a weight focus, if you wanted to lose weight,

you have to take in fewer than you're burning up. So you're counting your calories out, you're exercising more, and you're really monitoring what you're putting in your body and being more cognizant of how many calories those are. You might want to cut back 500 calories a day or a thousand calories a day. There's sort of algorithms and formulas for how much you would need to cut back to lose a pound of weight, and it could all be math. Hi, I love that you're here to learn if counting

calories is useful or not. If you haven't already, please hit follow in your podcast player, so you'll know whenever a new episode arrives. This will really help us to continue our mission to improve the health of millions. I mean, it all sounds so simple and obvious, right? You just work out how much you're burning today from like walking around and, you know, just your body doing its normal stuff. You count how much you're eating. At the moment, it'll be the same. Just reduce it and, you know, hey, presto. On this diet, does it matter what you eat or is it only about the total number of calories that you eat each day? This is a great question. So this is sort of gets at the question, is a calorie always a calorie? And at some level, it really is just a calorie. It doesn't matter

what you get it from. But when you take this to an extreme, it doesn't work. If you say, okay, here's a certain number of calories from a bowl of chickpeas, and here's the same number of calories from table sugar. Are you telling me it would be the same thing? No, because if you were eating the table sugar versus the chickpeas, one would be more satiating. You would fill up faster. Yeah, it's bulkier. And so in that level, a calorie isn't always a calorie. Another way this is problematic is some of these calories that the food industry has figured out is if they layer salt, sugar, and fat together, they can make you still feel hungry after you've eaten. If you're trying to count them, you're still hungry. It's been absorbed so fast that you still feel hungry after you've eaten. If you're trying to count them, you're still

hungry. It's been absorbed so fast that you're still hungry. And so the issue isn't just counting them. It's how full and satiated are you and how deprived are you? The calorie counting diet is usually for cutting back on 500 or 1,000 calories a day, which is immediately depressing, isn't it? Oh, I'm gonna be miserable. I'm gonna be hungry all the time. Hi, I'm Zoe's US Medical Director, Dr. Will Bolsowitz, and I'm excited to tell you about a free resource that's going to kickstart your journey to better gut health.

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and start feeling the benefits of a healthier gut today. Well, actually, tell me about that. So what happens in your body if you are eating fewer calories because you're following this calorie counting approach? As I suspect, many listeners on this podcast will have done it at some point in their lives. Sure. And it really does make mathematical sense. So if you haven't taken in enough calories to support your activities for the day, you have to rely on calories that you stored for later. The most efficient way we store calories is in fat. So here's kind of a little fun fact. So picture this. Protein and carbohydrate

in your body are associated with water. Your lean muscle has water in the protein. The glycogen, which is the storage form of carbohydrate, has water associated with it. And so the glycogen in your muscle and the glycogen in your liver are carbohydrate stores. But if you wanted to store up enough for a week or a month, you would be hundreds of pounds heavier. Fat excludes water. When we evolved, we said,

oh, this is such a cool way to store energy in case there's a famine tomorrow. I've got all this energy stored up that'll carry me through. And it's not making me heavier because the fat that excludes water is not heavy. It's a calorically dense, rich source of energy for the famine. Way for our body to store energy if there's a famine. You know, there's no food available as we're hunting and gathering next week. And so because it's so efficient and there's food everywhere and there's very few famines, we're also really good at just storing excess adiposity, excess fat. So it really does make sense.

If you have a caloric deficit, you will use your stores, and most of your stored energy is fat, and that's what you wanted to get rid of. So it sounds great. You have a caloric deficit, and you'll get rid of all of that fat. And one of the reasons you would want to lose that fat is not just about weight, right? For a lot of people, if they've got too much, it's been stored in unhealthy places. So actually reducing your weight can be really good for your health, I think. It could. But let's go back to being miserable. So people don't like being hungry. They're grumpy. They're anxious, right? So this idea of being in a deficit

is very temporary. So they'll do it and they'll be stoic about it. And then they'll go, this is the idea of going on a diet that you will go off of. So the best diet you can be on is not a diet because you don't ever wanna go off it. You want it to be lifestyle, not a diet that I go on and off. So part of it is choosing something

you can always do forever and you shouldn't have to be stoic and you shouldn't have to be miserable. But another really important side to this is how bad we are at counting calories. It completely undermines the effort. And just before we go on to that, because I think I was brought up with this idea that it's pretty straightforward. You count the calories, you eat less, and then it's just a question of whether you have good willpower. People with good willpower can follow this and you can lose as much weight as you want.

You know, that's what we were told. But I understand that, you know, the science now has really shifted from that view. So I love that you brought up the willpower thing because this is a psychological problem with this whole area. So as you cut back on calories and you are losing weight,

your body kicks in and says, what's going on here? I think I'm starving. I think I should be more efficient with all the metabolic things that I'm doing. I'm gonna protect myself from that weight loss. And your body starts to fight back. And so you might lose a few pounds and then that weight loss will get slower and slower.

And then you'll be really hungry. And so what is your body? How does the body fight back? What is that? And it fights back and it makes you hungry and you eat more. And then part of your reaction is, oh, I don't have willpower. Oh, I'm not a good person. There's something moral going on here.

I'm a failure in life. When in fact, it's really metabolically set in your body to try to protect itself. It's not you personally that has the low willpower. It's set for you try to maintain what's being stored in those fat cells that you created. And so psychologically, it ends up setting you up for a cycle of disappointment that's really unhealthy. Hi, I have a small favor to ask. We want this podcast to reach as many people as possible as we continue our mission to improve the health of millions. And watching this show grow is what motivates the whole team at Zoe to keep up the really hard work of creating new episodes each week. So right now, if you could share a link

to the show with one friend who would benefit from today's information, it would mean a great deal to me. Thank you. And you were talking about how our metabolism itself also changes as we sort of cut back the calories. Could you explain what's going on there? Oh, the best example of this comes from a somewhat odd study that Kevin Hall did with The Biggest Losers, which was a

weight loss game show that happened where people would lose hundreds of pounds in a year, which is an at a rate that was too fast to be realistic. There's a couple of major components to how much energy we burn. And one is just called the basal metabolic rate. So if you're just lying in bed, not moving, your heart, your lungs, your brain would be using metabolic rate. So if you're just lying in bed, not moving, your heart, your lungs, your brain would be using energy. And then if you got up and moved around, you'd be using some energy that way. So an interesting part of maintaining a calorie balance is what is your basal metabolic rate?

This thing that's just functioning. So they measured some of these people before and after this weight loss. And six years later, quite a few of them had gained most of the weight back after successfully losing hundreds of pounds. And one of the saddest findings that they got, now this is a study of, I think, as few as six people. So it's not super scientific, but it's really informative. After they gained the weight back, their metabolic rate was lower than it had been before they lost the weight. And that means while they're doing nothing, they're burning fewer calories than they were before they went through this process. Basically, your body has responded to this starvation and said, wow, this is like dangerous.

I just need to reduce the amount of calories I'm burning. And so then they have to eat fewer calories than they did before to maintain their old excess weight, which is, okay, now I have to deprive myself to be at the same weight I was before. So given all of this conversation, and I guess the background that we've been trying calorie counting for a hundred years, and really sadly, levels of obesity and type 2 diabetes are just continuing to go up at this incredibly alarming rate. Why is it still a diet that is so officially credited? So it just makes so much sense. But there's two parts that we haven't really addressed here.

One is people are really bad at counting calories. So I have to, in my diet studies, people have to tell us what they're eating. And quite usually they come across as underreporting the number of calories that they're eating. And I look them in the eye and they're either underreporting, which is quite usual, overreporting, which is less usual, forgetting, or lying. And so it is hard to see, did I eat a half a cup or did I eat this many ounces? I have to guess. I don't want to take the time to weigh it all out and measure it.

So we're just not very accurate at counting it. So what's your verdict on calorie counting then? I actually think, and this is almost true for almost any diet, almost any diet you come up with will work for someone. And I guess this comes back to this idea of personalization. Somehow it has met your needs in a way that the other diets have, and this one does work for you. So even when somebody comes to me and says, Professor Gardner, I'm on this crazy diet, but it's working. I never look them in the eye and say, well, you are wrong. It's not working. It's like, oh, I can see. And you're being honest and you try the other things. I think calorie counting does work for a few people. I don't think very many

people can do it accurately or successfully. So my preference would be to choose another way to do it. Brilliant. And I think that the scientific literature basically bears this out, doesn't it? That when you look at the average results for calorie counting over time, basically it doesn't work. It's short term, not long term. And we're after long term solutions here. Amazing.

Tomorrow on to another diet. I can't wait. Thank you, Christopher, for adding up the pros and cons of calorie counting in today's conversation. Part of our special series of daily episodes about diets and our health. I'm Jonathan Wolfe. And I'm Christopher Gardner. Join us tomorrow when we're looking at foods that are said to be good for the heart and focusing on the Mediterranean diet. As always, the Zoe Science and Nutrition podcast is not medical advice. It's for general informational purposes only. See you next time.