Your Metabolism Isn't Broken (But It Is Adapting)

Most of us have heard of “starvation mode”, the idea that if you eat too little for too long, your body eventually stops losing weight and holds onto every calorie. But is that actually what happens?

In this episode, we unpack what really happens to your metabolism during prolonged calorie restriction and why the popular idea of “starvation mode” gets metabolic adaptation wrong.

We look at two of the most famous (and frequently misunderstood and misrepresented) examples in the history of weight loss research: the Minnesota Starvation Experiment and The Biggest Loser.

The Minnesota study showed just how dramatically the body can respond to prolonged energy restriction, while The Biggest Loser became famous for findings suggesting that some participants experienced substantial metabolic adaptation after losing large amounts of weight.

In this episode we discuss:

• What exactly is starvation mode?
• What is the strongest research we have in support of starvation mode?
• Why do people misrepresent this research to support an argument that is factually incorrect?
• What actually happens to your metabolism when you lose weight?
• How much can metabolic adaptation really explain?
  
  

We separate what the science actually shows from the common claims you see online about starvation mode, metabolic damage, and “damaged” metabolisms.

P.S., If you want to support us and would like monthly lifting workouts, you can join the Momentum by Sohee fitness app. http://momentumbysohee.com

If you are interested in fat loss science, you can purchase Ben's best-selling comprehensive fat loss book, Everything Fat Loss. http://geni.us/EverythingFatLoss

Transcript

SPEAKER_00 0:00

Have you ever heard someone say you are not losing weight because you are eating too little? Or if you want to lose weight, you need to start eating more? These ideas are everywhere, but where did they stem from and what does the research actually show?

SPEAKER_01 0:15

This belief that starvation mode is something that your body goes into when you drop your calories too low keeps people afraid of being in the thing that actually reliably works for weight loss, which is a consistent energy deficit, and perhaps has them eating more food when they should be doing the opposite for their goals.

SPEAKER_00 0:35

So this episode is going to be about something called starvation mode. And that is the perhaps population level definition. That's that's the way that people describe it. But we are going to talk about something called metabolic adaptation or adaptive thermogenesis. So we're going to go into some of the science, but we are going to talk about the misconception that is starvation mode. First and foremost, most people have no idea what starvation mode actually means. If someone said to you you aren't losing weight because you are not eating very much, you need to eat more, and you ask them what starvation mode actually meant, chances are they're going to say different things to someone else who also believes in starvation mode.

SPEAKER_01 1:19

Yeah. So there's going to be two claims that we'll be addressing when people say starvation mode is a thing. The first one is this idea that when you drop your calories to be in a calorie deficit, your body holds on to every morsel of food and refuses to drop body fat, or sometimes you might hear people say that they even gain they gain weight when they drop their calories. Now, this is the part that is an actual myth. This does not happen.

SPEAKER_00 1:46

Complete bullshit.

SPEAKER_01 1:47

Yeah.

SPEAKER_00 1:47

Complete bullshit. When people say starvation mode is a myth, that is often the thing they're talking about. But I think one of the issues when people say starvation mode is a myth is it means that they miss a useful and more important conversation about what starvation mode might actually mean. So the other definition could be something like when you lose weight, your metabolic rate adapts to the fact you're eating less food and losing weight becomes harder over time. So you become more susceptible to holding on to body fat for the same calorie intake than you used to. Basically, losing weight gets harder over time. And that is a very fair definition.

SPEAKER_01 2:30

And that's known as metabolic adaptation, or you might people you might hear people say adaptive thermogenesis. That part is legitimate and is supported by the research, and we'll go into that more uh in the next few minutes here. So basically, what we're saying is that there's two different claims that people tend to make when it comes to talking about starvation mode. The second claim, which is this idea that Ben covered, uh, that your metabolism drops disproportionately to the reduction in your body weight. That does not disprove claim one, which is that your metabolism refuses to drop body fat at a certain point. That does not happen.

SPEAKER_00 3:11

Right. Yeah. So what we're going to do in this episode is make the best case for starvation mode so you can actually understand what people are talking about and where they're tripping up. Because we think the better you understand it, the easier it is for you to know what is bullshit and what isn't. So rather than saying starvation mode is bullshit and then glossing past it, we're going to go into the reasons why some people might believe this. So, first and foremost, weight plateaus are real. If someone reduces their calorie intake and they start losing weight, and their metabolic rate can reduce for various reasons, which we've talked about in previous episodes, we don't need to go over now. But if someone reduces their calorie intake by, say, 500, they lose weight, and after a while, they stop losing weight. They have hit a weight plateau, their metabolic rate has adapted, and they have stalled.

SPEAKER_01 4:06

Yeah. But it does not mean that your body has gone into starvation mode. It's a totally normal and expected part of the weight loss process. And I do feel like people premature when when they reach a plateau, they prematurely sometimes a knee-jerk reaction is, oh, I'm not losing at a steady clip like I used to, therefore I must be in starvation mode.

SPEAKER_00 4:24

I think a very important thing that we should emphasize is that people essentially pathologize something that you have rightfully said is very normal.

SPEAKER_01 4:35

Yeah. Also, especially if you're only relying on scale weight to track your fat loss or your weight loss progress. We know that there are a lot of different factors that will influence scale weight, such as increased sodium intake, um, you know, your bathroom habits and so stress, bad sleep, and so on. So I do feel like sometimes people will conflate a plateau with my metabolism's dead. Yes. Or or maybe you are losing body fat, but you're holding on to more water than usual. Maybe it's, you know, your I said that that time of the month for you and your menstrual cycle. So there's many reasons why the scale weight might be at a certain level, even if you're continuing to to make body fat loss progress.

SPEAKER_00 5:16

Yes.

SPEAKER_01 5:16

And I would say let's do a proper audit of your progress first before we jump to that conclusion. Yes. That's my addition.

SPEAKER_00 5:23

But metabolic adaptation is something that you can measure. When I say you can measure, you actually can't measure it. In research, it can be measured. It is not imaginary. Whereas starvation mode has just become this kind of like a boogeyman scary term.

SPEAKER_01 5:40

Oh, you're not losing weight because you're eating too little. So you have to eat more to see the progress that you want.

SPEAKER_00 5:46

Yeah. But I think too much too many people throw around the phrase starvation mode without actually defining what it means. And I think that's why people get so confused.

SPEAKER_01 5:53

The other argument people make with starvation mode is that the longer and harder you diet, the worse you're going to feel, especially in terms of increased appetite, increased cravings. You might notice things like increased uh food rumination, where you start looking up more recipes or what we call food porn on social media, where you look up, you know, delicious meals and snacks and things like that. That does happen. That is also a documented phenomenon that does happen in people who diet for too long and for too hard.

SPEAKER_00 6:22

Yeah. Can we dive into the research? Yes, let's do it. So I have intentionally picked the best arguments that are used because then we are going to systemically dismantle them. Is that the right word? System systematically. Yeah. Systematically dismantle these arguments so you can fully understand uh the research on this topic. So we are going to begin way back in the 1940s with one of the most extreme weight loss trials ever. So this research paper is called The Biology of Human Starvation, or more commonly known as a Minnesota Starvation Experiment. And what it did is something that is not likely to be replicated. You are going to realize why this is such an extreme trial. So back in 1944, uh 36 male conscientious objectors to war volunteered to be studied the effects of semi-starvation and subsequent refeeding. This is not a weight loss trial. This is a literal quote unquote starvation trial.

SPEAKER_01 7:32

Yeah, basically, because they were coming to the end of World War II, there were a lot of people out there who were legitimately starving. They had never studied this before. They don't know what to expect in terms of physic physical effects, uh psychological effects, and also what will happen once they have access to more food again. So they said, okay, let's study this in a controlled setting.

SPEAKER_00 7:50

Yeah. Now, this is a research paper that is frequently used by people in the kind of anti-diet community to warn people about the effects of dieting and calorie restriction. And I think that is I think it's okay if you explain it well, and I think it's really terrible if you explain it badly. And we're going to get to that in a second. But what I need you to know is if you're not watching this on video but you're listening to it, you need to understand that the guys who volunteered themselves for this were not people who would normally volunteer for a weight loss study. They were not going in with say high levels of body fat. Yeah. Yeah. They didn't have a high BMI, they didn't have a high level of body fat. They were going in with quote unquote, or as much as I hate the term, they were normal, normal weight, and then they were going through a starvation protocol. This isn't the same as someone who uh would describe themselves as 100 pounds overweight who is then going on a weight loss protocol. That is not the same thing.

SPEAKER_01 8:51

Yeah. Basically, what they did was for a period of 24 weeks, again, in a controlled setting, these participants had their food intake cut roughly in half with the goal of reducing their body weight by 25%. That means that if someone was, let's say, for easy numbers, 200 pounds, they had to reach 150 pounds by the end of the 24 weeks. And basically they would track their progress, and according to how your body weight drop was progressing, they would adjust, tinker with your calorie intake to ensure that you were on track for to meet that, to meet that goal by the end.

SPEAKER_00 9:24

Yeah. So needless to say, by the end, the guys were very, very, very thin. And the photos that document this, you could literally play the xylophone on their ribcage. They look like people it if you saw photos of them, you you would be worried for their health. Yeah. That level of thin. And dieting to that level of thinness, not that this was an intentional weight loss thing, like intentional dieting. They weren't dieting for a show or whatever, but it came with many, many very terrible side effects, including things like hair loss, extreme fatigue, dizziness. Uh, they were thinking about food a lot. Some people even said they were dreaming about food. Some people collected recipes, which, as Zohi has said already, is often common when people look at food porn on Instagram when they're dieting. And they became so cold that they often requested extra blankets even in summer.

SPEAKER_01 10:19

Yeah.

SPEAKER_00 10:20

Lots of very, very terrible side effects. Yeah.

SPEAKER_01 10:22

They also had mood disturbances, and I feel like as we're listing out these side effects, some of you will resonate with, oh, that's happened to me before when I would try to crush diet too hard, or whatever. So they became extremely moody, very negative, lost their sense of humor. Uh, and also they all they experienced things like anemia, neurological deficits, and swollen legs, ankles, and face. Basically, not great things happen to them.

SPEAKER_00 10:43

Now, I think it is important when I say that people in the anti-dieting community sometimes use this unfairly. I think there are some useful parallels that can be drawn here. So if you look at bodybuilding research, bodybuilders or fitness models or fitness athletes or competitors or whatever, when they diet down to very, very low levels of body fat, even in research papers, they will often acknowledge some of these things as well. So, for example, when I was at my leanist, I was thinking about food all the time. Absolutely, that was probably the worst side effect. My libido was non-existent. I was cold all the time, again, even in summer, English summer, admittedly, but I would often go to the gym and train in an extra hood even when I was lifting because I was so cold, I wouldn't sweat even if I was lifting hard. Uh, I was cranky, I was pretty grumpy, my sleep was terrible, lots of similar things. But my hair didn't fall out. Uh, I didn't get dizziness like they got. So there are some parallels, but not all of them.

SPEAKER_01 11:49

Yeah. Now, let's talk about what happened to their metabolism from the baseline to the end of a study. Their resting metabolic rate dropped by 40%, 4-0. Now, a lot of people who push the starvation mode argument will say, therefore, this is evidence that starvation mode exists.

SPEAKER_00 12:11

Yeah, the idea that your metabolic rate has reduced by 40% sounds obviously catastrophic. Now, there are different components to metabolism, and we don't want this to get too nerdy, but in general, when we talk about resting metabolic rate, that's the number of calories or the amount of energy your body burns when you're doing nothing. So even if you're lying down all day for 24 hours, your body is burning a certain amount of energy, breathing, keeping your organs functioning, keeping you alive. Yeah. So if their resting energy expenditure dropped by 40%, you're like, oh my god, their metabolism's crashed 40% reduction. But you have to keep in mind that their body weight itself dropped 25%. So metabolic adaptation, or otherwise known as adaptive thermogenesis, is when your metabolic rate reduces or adapts disproportionately to how much weight you lose or gain. Right. So in this instance, if people lose 25% of their body weight, but their metabolic rate reduces by 40%, metabolic adaptation is that 15% difference between the two. So in this instance, yes, their metabolism did decrease above and beyond what you would expect, but the full 40% is largely accounted for by how drastically they lost weight.

SPEAKER_01 13:25

Yeah. Now, if starvation mode were a real thing, we would have seen in this participant the 40% drop in metabolic rate, along with no weight loss happening, or at least it would have stalled at some point, but we didn't see that happen. They s they all all the participants who completed the study saw the 25% drop in their body weight from beginning to end. So even though the metabolic rate did adapt, they still lost substantial amount of weight.

SPEAKER_00 13:48

I should have said when I was talking about numbers, but the what that actually equates to, that 15% difference, is approximately a couple of hundred calories per day. So what that means is if someone in theory on paper should be eating 2,000 calories to maintain their weight, it might be 1800. So that's not great. Like you don't want to eat less food than necessary. Yeah. But it also isn't the difference between being able to lose weight and gaining weight in a deficit. Like those aren't the same thing. Yeah. You get that.

SPEAKER_01 14:19

Yeah.

SPEAKER_00 14:19

Hopefully.

SPEAKER_01 14:20

Yeah. But then, of course, outside of the actual weight loss portion itself, I do think they are some legitimate red flags that people bring up in terms of what happens in the aftermath. So in the in the months and years after the experiment concluded, they found that a lot of the participants, uh, their appetite shot up disproportionate to uh how much weight they had lost. This is very important. And so a lot of times, um, sometimes they would re- not only regain the weight that they had lost in time, but they would actually go beyond that. And that's called body fat overshooting. And I specifically remember reading about one of the participants who was later interviewed. He said, I felt like I had a cavity that could not be filled with no matter how much food I ate. And another person said, even though I would eat until my stomach was physically full, I did not feel satisfied. And then another participant said, when they were finally released from the weight loss portion, he ate so much that he had to go to this the hospital to get his stomach pumped.

SPEAKER_00 15:18

Now, this is something that I do think there is a useful parallel to people who follow extreme diets. And again, if we take this back to bodybuilders, how many bodybuilders and physique athletes will openly admit that once they finish their show, they will find themselves uncontrollably binge eating. Right. So, as an example for me, I remember after my photo shoot, I'd been dieting for however many weeks. I got to very, very low levels, unhealthily low levels of body fat, and my appetite was insatiable, the hungriest I have ever been by a fucking by country mile. And I remember I was like, okay, I can now eat more food, I should start regaining weight. And I had this huge uh plate of chicken and potatoes, like it looked like it was feeding probably three people, way more food than it's a good one.

SPEAKER_01 16:07

Was that what you were actually craving?

SPEAKER_00 16:09

No, that was like my typical meal, but I increased the quantity. So I was like, okay, I can start eating more food. Here's my regular meal, but I'm gonna increase the quantity. So I probably ate two or three times what I normally would for my diet phase. And then when I finished, I was like, wow, I'm still hungry. I thought that would fill me up. So I made a huge bowl of porridge. And when I say huge bowl, you know that I will often eat it from the saucepan. I won't even put it in a bowl. I eat a lot of porridge. Then I had a huge portion of porridge, which is one of the most satiating foods.

SPEAKER_01 16:32

Also potatoes, too, which you already had eaten. Yeah.

SPEAKER_00 16:35

Yeah. So at this point I had probably eaten enough food for I would say maybe four people, regular portions, and I was still hungry. And then I remember going through the snack cupboard and I ate an entire box of brownies. I ate an entire box of caramel chocolate shortbread. I remember I then ate something else. I can't remember. Oh, I ate an entire bag of haribo, like a family-sized bag of haribo. I was still hungry. I think I then ate maybe a whole punnet of grapes, still hungry, and I ate like an apple, still hungry. So at this point, I don't know how many how many thousand calories I've put away. Yeah. But I have eaten relative to what I was eating during my dieting phase, probably I don't know, seven times as much food as I would eat a normal I was gonna say several days worth of food. And I at the end I was still hungry. At once. Yeah. So this is an example of when people have gone through a dieting phase, if their appetite becomes so insatiable that they then regain, like Sohi said, they overshoot and they will often go back above and beyond where they started. So a lot of bodybuilders I know people who have said, Well, I lost 20 pounds dieting, but then in the month afterwards I ended up gaining 30, for example. This is a very important thing to acknowledge.

SPEAKER_01 17:50

Yeah, and I and I I would say we do agree that this style of extreme dieting is not an approach that we recommend anyway, but we do see people then use this study as an argument against diet all any type of dieting. But the reality is we know this is not how most people diet. How many of you cut your calories in half when you're dieting?

SPEAKER_00 18:08

So uh yeah, and also the bit that I think we just just need to extra drum home again is the reason I th the biggest reason why I think it's such a red flag when people say dieting's bad for you, calorie deficits are bad for you, because here is what happens, and then they cite this study is they took men who were already lean and then cut their calories in half. Getting people to unhealthily low levels of body fat, the side effects of that cannot be translated to a regular person trying to lose 20 pounds or whatever.

SPEAKER_01 18:43

Yeah. Now let's fast forward to several decades later. We're gonna go to 2012. There was the biggest loser study that was published. Many of you will be familiar with the biggest loser TV show.

SPEAKER_00 18:53

In England, it's not so popular, so maybe describe it outside of America.

SPEAKER_01 18:57

Basically, it's a weight loss competition where participants with very high body fat compete for a prize at the end. They are subjected to extreme crash diets and hours and hours of exercise per day. And they have, I want to say they have weekly weigh-ins where there's a big screen that shows their body weight, they step on the scale and it shows how their body weight now compares to the week before. Yeah. And then basically you're like, oh, I'm s if you lose, if you don't lose enough weight. I've we've seen clips of participants basically apologizing to their coach.

SPEAKER_00 19:31

Yeah, we've seen people that there are literally clips where guys have lost, say, three or four pounds in a week and then they've apologized, which it's very sad. Yeah, yeah. It's very sad. Um now this probably doesn't need explaining, but let's reiterate it. I don't know what what does what's the word for reiterate if you say it first? Because we're not reiterating. It's like pre emphasize. We're like pre-iterating. So we're gonna pre-iterate that a televised weight loss contest is not representative of how most people diet. Yeah. So the biggest loser, um, I should be slightly careful because I know for a while they were very trigger-happy on lawsuits. A televised weight loss contest in general tends to encourage people losing weight as quickly as possible.

SPEAKER_01 20:20

Yeah.

SPEAKER_00 20:21

As in, people will often exercise four to six hours per day or more. They will cut their calorie intake by a huge amount, and it is essentially glorified crash dieting with a prize at the end.

SPEAKER_01 20:33

Yeah, because honestly, how many people want to watch a modest deficit with a with a slow rate of weight loss progress?

SPEAKER_00 20:39

We followed people for a year and we measured how many healthy habits they implemented with the world.

SPEAKER_01 20:43

With a compassionate coach who's not screaming in your face, that's not gonna get as many views.

SPEAKER_00 20:48

The biggest loser was more like if you stop running, I'm going to punch you in the face. I think that was something similar to clips I see. And also, I want you to run until you throw up. I need to see you throw up. Yeah.

SPEAKER_01 21:01

That's also an approach that we would never recommend.

SPEAKER_00 21:04

Yeah, we don't tend to encourage exercise bulimia. Correct. Yeah.

SPEAKER_01 21:08

Okay, let's talk about the results.

SPEAKER_00 21:11

Yes, so results. So when I say that this isn't representative of how most people diet, in 30 weeks, the average weight loss was 58 kilograms. Yeah. Nearly two kilograms a week. That's over four pounds per week on average. That's a lot.

SPEAKER_01 21:31

Extremely fast, extremely aggressive weight loss. Definitely not sustainable to keep up that rate of weight loss progress for a very long time.

SPEAKER_00 21:37

Most medical professionals, if you ask them what a quote unquote healthy rate of weight loss is, would not be saying that. I think that's fine. We can leave that there. That's self explanatory.

SPEAKER_01 21:46

Um, what was cool was that the vast majority of the weight loss was fat. Roughly 80% of the weight loss was fat, and then the remaining was fat free mass. This is a good thing. Uh, and I'm pretty sure it was attributable to attributable to how much exercise. They were doing to help retain.

SPEAKER_00 22:02

Yeah, so I've got the numbers here to try and get them precise. So when they measured their resting energy expenditure or resting metabolic rate, uh, it based on their body composition, their predicted level was around 2,400 calories. That is how many calories they should have been burning based on how much they weighed and what their body composition was at the time. However, their actual resting energy expenditure was closer to 1900 calories, meaning that the metabolic adaptation portion was in the ballpark of around 500 calories. Yeah. Which is again, that's not ideal. If ideally, if if based on how much you weigh, you should be eating two and a half thousand calories, but actually you have to eat two thousand. Yeah. That sucks. Like you don't want to do that.

SPEAKER_01 22:53

Not great news. No. But the thing worth pointing out here is that they did have their metap the metabolism adapt, but at the same time, they still lost extreme amounts of weight. So even though adaptive thermogenesis did occur, they were still able to successfully drop weight. So there was no starvation mode seen here.

SPEAKER_00 23:12

That is going to be something we reiterate, but also pre-iterate for later, is that in this instance, you are observing metabolic adaptation in tandem with weight loss, not necessarily something that prohibits weight loss from happening.

SPEAKER_01 23:27

Yeah.

SPEAKER_00 23:28

Now, what we can do now is fast forward a few years because I actually did a follow-up paper, and the follow-up paper is the one that hit a lot of news story headlines. This was the one that a lot of people, again in the more kind of anti-diet community, really started driving home because this paints an even more bleak picture in terms of metabolic adaptation.

SPEAKER_01 23:51

Yeah. Basically, what they found was that their resting metabolic rate was still roughly 600 calories per day below baseline. So bef below where they initially were before at the beginning of the biggest loser competition.

SPEAKER_00 24:05

Now at this point, they had regained 41 kilograms of the original 58 that they had lost, which is a lot. They are still maintaining weight loss, but that is a substantial weight regain. And their resting metabolic rate was around 700 calories below baseline.

SPEAKER_01 24:23

Also, as far as the rate we regain, weight regain goes. Rate we gain weight regain goes, I feel like that is to be expected because how many of those participants will have kept up those extreme exercise and dieting behaviors in the six years since the competition was over.

SPEAKER_00 24:40

That is a good example of if you have people on an extreme intervention and then you kick them out of the door and you send them home. Is it realistic to expect them to carry on what they're doing? In weight loss research papers, if they say, Here's your diet plan, follow it for six months, and then at the end you don't know what to do. Yeah. A lot of people kind of go back to what they were doing before. Whereas more successful weight loss plans tend to have more periodic follow-ups, they tend to have more support, more ongoing accountability, because weight loss in the short term and weight maintenance in the long term are not the same thing.

SPEAKER_01 25:14

Yeah. They also found that six years after the biggest loser was done, their metabolism had still adapted by uh roughly 500 calories a day, meaning they were burning roughly 500 calories a day, fewer than expected.

SPEAKER_00 25:29

So a conclusion from the authors is that metabolic adaptation was a response to the ongoing efforts to maintain weight loss. Once again, metabolic adaptation did not prevent people from losing weight necessarily. In fact, one of the interesting things that they found is that the people who had lost and maintained the highest degree of weight loss were also the people that had the highest degree of metabolic adaptation. So the most successful people from a weight loss perspective had the most metabolic adaptation rather than metabolic adaptation is the thing that prevented weight loss. Right. So when people said dieting ruins your metabolism, it makes weight loss impossible, and they used this research paper, they conveniently glossed over and didn't tell you about the fact that metabolic adaptation happened in tandem with the most successful weight loss maintainers rather than the most unsuccessful weight loss maintainers.

SPEAKER_01 26:27

And if starvation mode were a thing, we would not have seen this happen, basically. Now let's fast forward to another study from 2020 with a very interesting title. It's called Metabolic Adaptation is an Illusion question mark.

SPEAKER_00 26:40

So here is the thing that I would like you to understand. This is going to be slightly nerdy, I'm going to do it really quick. So if you're measuring something like body weight, you can do it multiple times per month, per week, even per day if you want. There are some weight loss studies where they literally have people weighing themselves four times a day. It's very easy. You stand on the scale, straight number. Measuring someone's metabolic rate is not like that. It takes very fancy equipment, it takes time, and it's more of a process. So when you measure people's metabolism, normally it will happen twice. Once at the beginning of an intervention and once at the end. So if you get people to diet for 16 weeks, you can measure their metabolic rate at the beginning and you will measure it at the end. It isn't something that you tend to do week on week on week on week. The next thing that you need to know is because it's quite a finicky process, one of the things that can change the results is the amount of food you have been eating leading up to that point. Now, a parallel, I don't know if this will quite translate, tell me if this is a terrible analogy. Imagine that you're having your heart rate measured, but your heart rate can vary depending on what you were doing leading up to it. If you were resting, if you were asleep, your heart rate will be slightly lower than if you exercised an hour ago, for example, or you had a coffee or whatever. So the testing conditions can significantly influence the number. And that's important with metabolic rates specifically because it can change depending on how much you've been eating. So if people have been losing weight and then you measure their metabolic rate, for whatever reason, it can appear lower than if people have been gaining weight and you measure their resting metabolic rate. So this particular study did something that most studies prior to that hadn't done, including the ones that we've talked about already, which is they gave people an additional period of weight stability. So they got people to diet, but then they went through a weight maintenance phase to see how much the energy balance factor of how much they were eating influences their metabolic rate.

SPEAKER_01 28:47

Yeah. And basically when what they found was when they introduced this four-week weight maintenance period and then they meant measured their metabolism, the metabolic adaptation was actually cut in half. So as we saw, uh dieting versus in what you call uh calorie balance, I guess, right? Eating the same number of calories as you expend, so you you maintain stable body weight. Metabolic adaptation was far less, which is a very good thing.

SPEAKER_00 29:16

I think you might have said metabolic adaptation.

SPEAKER_01 29:19

Possibly.

SPEAKER_00 29:20

It's fine. It was close.

SPEAKER_01 29:22

You guys know what I mean.

SPEAKER_00 29:23

You know what I mean. Yeah.

SPEAKER_01 29:24

Yeah. Basically, the weight stabilization helped a lot with reducing the metabolic adaptation.

SPEAKER_00 29:29

Yes. And once again, metabolic adaptation did not predict weight regain. So if someone loses a lot of weight and then you measure their resting metabolic rate and it's lower than normal, you can't use the fact their metabolism has dropped as evidence that they can't lose weight because they are showing you that they have lost weight despite that. Yeah. So basically, what you need to know is sometimes in research studies, measuring people's metabolisms, sometimes you can get kind of funky results. Yeah. And you have to take them with a pinch of salt. Yeah.

SPEAKER_01 30:05

We also want to know as well that one of the takeaways here is that when your metabolism is measured while you are in a deficit, that does not mean your metabolism stays at that level. Once you bring up your calories, your metabolism will also come back up.

SPEAKER_00 30:23

Now we are going to fast forward to 2022. And the reason this is important is because one of the authors of both of the biggest loser papers that we have talked about already actually did a follow-up paper where he talked about the biggest loser papers and he specifically called out the fact that they were often reported as dieting crashes your metabolism and all of these scary headlines. And I think that if one of the authors, one of the researchers themselves, says that people are misrepresenting their research, I think it's important you listen.

SPEAKER_01 30:58

Yeah. His name is Kevin Hall. Some of you may be familiar with the name. He's a big, big researcher in the world of energy balance. Unfortunately, he's now retired for reasons that we won't get into on this episode. But anyway, he's a big deal. You'll see him on a lot of the energy balance in calories in, calories out, those kinds of papers. But he wrote in this paper, I quote, our data were widely misinterpreted as evidence that weight loss diets, quote unquote, destroy metabolism, and most lifestyle interventions are doomed to fail.

SPEAKER_00 31:27

Also, he reiterated that with the biggest loser paper, despite the fact that the results were pretty terrible, they were pretty terrible, saying that people have regained a majority of weight that they've lost, but their metabolic rates are significantly lower than they should be, those aren't great headlines. But he did point out that people were still maintaining a kind of 12% weight loss, which if someone has lost 58 kilos and then regained, was it 41? 41. I can't remember the numbers. Say 41 kilos. That obviously sounds like a very, very big weight regain. But it's also, I think, kind of unfair to make it sound like people have failed when they are still maintaining a fairly substantial degree of weight less than they were at the from the very beginning.

SPEAKER_01 32:09

Um and they also found that the largest degrees of metabolic adaptation were found in those who did the most extreme exercise, basically. But that points to they were still successful at losing the weight.

SPEAKER_00 32:24

So this bit I don't want to go into too much because this is kind of more of a hypothesis, but he theorised that's a word, isn't it? Yeah. Yeah. He theorized this is sleep-deprived brain. I s I think I've got things wrong a lot. He theorized that possibly one of the reasons why it looked like people's metabolic rates were lower than expected was because of the extreme amount of exercise they were doing. So in the biggest loser, not just the biggest loser studies, but across the biggest loser TV shows, some participants will say that they were exercising four to six hours per day or more. Right. Which is a lot.

SPEAKER_01 33:03

Right.

SPEAKER_00 33:03

And I I don't know anyone.

SPEAKER_01 33:05

Unless you're a professional athlete, what recreational exerciser is gonna say, Oh, I'm gonna keep four up four to six hours a day for years and years and years.

SPEAKER_00 33:12

Yeah, so there is a theory, there's something called a constrained model of energy expenditure. And what it means is if you go and do a hard workout and you go and do a really intense run, but then you get home, and because you worked out really hard, you're a bit more tired than normal. So perhaps you spend the rest of the day lying on the sofa. So even though you've burned more energy from your workout, you can compensate by reducing how much you burn elsewhere. And it's more complicated than that, it isn't necessarily exercise versus laziness and energy levels, but essentially it's kind of pushing and then simultaneously pulling. So you might burn 500 calories from a workout, but then you might save 200 or 300 elsewhere because you feel more lethargic than normal. Yeah. So he thought that maybe the fact that these participants were exercising several hours every single day, he thinks that might have been one of the reasons why their metabolic rates were lower than expected. And again, that does not translate to your regular person who is exercising. I mean, most people aren't exercising an hour a day, let alone four to six hours. Let's say 30 minutes. Yeah. Basically, I mean, I would love it if everyone exercises. A much more modest amount than the four to six hours that they were doing during the But the point is if one of the authors of the scariest research papers, or two of the scariest research papers when it comes to quote unquote starvation mode, says people are misrepresenting my research, listen to that.

SPEAKER_01 34:41

Yeah. And hopefully you can put that in your back pocket for when someone tries to argue that a starvation mode is a thing. You can pull out that specific quote.

SPEAKER_00 34:49

Now, final nail in the coffin. I don't think we need another nail outside of this. We could if we wanted to, but I think this is The coffin is fully shut.

SPEAKER_01 34:59

Yeah.

SPEAKER_00 34:59

So now we are going to say same year, 2022, but there is a systematic review and meta-analysis, which looked at essentially a meta-analysis is like a study of studies. So think of all the studies that looked at metabolic adaptation and they pulled them all together and analyzed all of them to come with an overarching conclusion. When a meta-analysis is published, those are the kind of things that you're supposed to listen to.

SPEAKER_01 35:26

Yeah. And they found that when they measured resting metabolic rate after weight stability period, so weight maintenance phase, the metabolic adaptation was very, very, very little. This echoes the study that we went over two studies ago, which found there is a difference when you measure metabolism when they're dieting versus when they're maintaining their weight.

SPEAKER_00 35:47

Yeah, and to to give the, let's say to give the starvation mode the the benefit of the doubt, if you will, like we're trying to explain why people might have that impression before we dismantle it. So it had 33 studies that looked at metabolic rate and components of of metabolism, and it found that there was metabolic adaptation or adaptive thermogenesis in 27 of them. So a majority of studies did identify some form of metabolic adaptation. So in general, yes, it is very commonly seen in research literature that when people lose weight, their metabolism will decrease above and beyond what you would expect. But then they said when you looked at the best design trials, that tended to disappear. So in the same way that we have talked about studies that show the highest degree of metabolic adaptation that you can find in the research literature, but then in newer trials where they had more rigorously designed to get the testing methodology right by bringing in a period of weight maintenance and testing it more than once, that disappears. So basically, you will see metabolic adaptation in lots of studies across the research literature, but when you look at the most meticulously designed ones, they tend to show a much smaller degree than the big scary headlines that you see in the Minnesota Starvation Experiment and the Biggest Loser paper one and two. Yeah. Which again, to reiterate again, if you see people talking about the risks of dieting, and they cite the Minnesota Starvation Experiment and the Biggest Loser paper, and no other studies, they are cherry-picking. Right. End of fact.

SPEAKER_01 37:29

But also, as we've gone through the methodology of both these papers, the the papers don't actually support the arguments that they're even making. That is, yeah, that's important to which is that diet quote unquote diets don't work. They definitely did work in the studies.

SPEAKER_00 37:43

Those research papers show some of the deleterious effects of dieting for sure. Yes. They show some of the risks of doing extreme crash diets for sure. They do not support one that starvation mode is a thing and you can't lose fat in a deficit. Two, they do not support that dieting in any context is bad. Correct. Which is a terrible conclusion that people have been taking from those studies.

SPEAKER_01 38:07

Are the same, and every time you diet, that's you're going to everyone's going to cut their calories in half.

SPEAKER_00 38:12

People on a televised weight loss contest did really extreme things. Therefore, you should never try and lose reduce your calories ever, intentionally.

SPEAKER_01 38:21

Okay. Anyway, with all of that said, someone may have gotten to this point and you might be wondering, okay, if starvation mode is not real, then how do you explain the fact that I am eating 1200 calories and I'm not losing any weight?

SPEAKER_00 38:34

So one possibility, an unfortunate possibility, is calorie under reporting. Yep. Which we have conveniently just done an episode on. So if you don't know, if you don't know how common that is, I would strongly recommend watching that. Yeah. I think that calorie under reporting is often something that people feel very defensive about. And especially when you have two kind of thin, fit personal trainers saying you're probably eating more calories than you think, it often feels very judgmental. And if you watch that episode, hopefully you'll understand why that's not the case when we talk about it.

SPEAKER_01 39:09

I mean, I remember when we were had Spencer Dodolski on on our podcast, he mentioned back when he was prepping for a bodybuilding competition, he star the more he dieted and the worse he felt, he started to sneak in with a what was what we call BLTs, bites, licks, and tastes here and there, where he would have some strawberries and he wouldn't report it. And he would, you know, basically his actual calorie intake would start to creep up and up and up, even though his prescribed and target calories stayed low.

SPEAKER_00 39:37

As far as eating off plan, I feel like snacking on strawberries.

SPEAKER_01 39:40

True.

SPEAKER_00 39:41

But I think that might be an example he gave. I think that's it.

SPEAKER_01 39:45

But he was I think he was eating several things throughout the day that of course would then add up to, let's say, a few hundred extra calories. And then that would that could be enough for you to stop seeing fat loss progress. And then he was telling specifically, he said he would tell his coach, Oh, I'm I'm not deviating from the plan.

SPEAKER_00 39:59

Yep.

SPEAKER_01 40:00

So anyway, that does happen, of course. And then again, go up, go back and listen to the full episode if you want, but we do acknowledge that a lot of under-reporting is unintentional. People don't realize that they're eating more than they are. Um, but of course, as we've uh covered with Spencer's example, it can also be a case of you are omitting information on purpose.

SPEAKER_00 40:18

Yeah.

SPEAKER_01 40:18

Yeah. The other one is reduced spontaneous movement, which uh Ben covered. It's again, it feels so weird to say your name. You covered in the when we talked about the constrained energy expenditure model, where um I would say when I was prepping, by the way, in my bikini competition days a lifetime ago, I had the exact same thing happen where the more my calories dropped outside of my actual workouts, I felt like I was sitting on the couch the rest of the day.

SPEAKER_00 40:43

Yeah, this is this is very important. So I I as as an example, the same thing. When I was dieting for a photo shoot and I was very, very lean, I noticed that when I was at the gym and I was spotting clients, I would often find myself leaning against things. So if I'm standing there while they're on a piece of equipment, I would find that I would lean or I would sit more. And I remember thinking, this isn't normal for me, but I remember feeling so tired that it felt like I was trying to conserve energy elsewhere. And that's an example of how different components of of metabolism can adapt to dieting. So for example, if you reduce you how much you're eating and you lose weight, your resting energy expenditure can reduce because you weigh less. A smaller human requires less fuel than a bigger human, all else equal. But if you also feel less energetic, you will then burn less energy through sometimes voluntary movement, but also involuntary movement as well, which are two different components of metabolic rate, which will reduce in response to losing weight.

SPEAKER_01 41:47

Yeah. Then we have water retention masking fat loss. We kind of talked about this at the beginning of the episode, where especially if you are one, relying solely on scale weight to gauge your progress, and two, taking your measurements very sporadically. For example, if you only take get on the scale once a month, that 30 days later, you might be on a day where you happen to be holding on to more water than usual. Maybe you had a pizza last night or more salt or something like that. And that's why I would say if you are pursuing fat loss, I highly recommend not only scale weight, but also waist measurement, which is a really good proxy for body fat, but also progress pictures. And having all of that proper context and all the complete data can give you much better information to tell you are you actually in a plateau? Because oftentimes you're actually you're not. That's not actually the case.

SPEAKER_00 42:35

Yeah, I I remember using an example where if you look at a weight loss chart, which tends to zigzag a lot. Right. Whoops. Tends to zigzag a lot. If you picked two days, even though a line trends downwards, if you pick two days a month apart, it could look like someone has either not lost weight or they've gained weight. So I think relying on weight alone and also relying on weight sporadically is a very easy way to be like, what the fuck? I'm not making any progress when that's not the case.

SPEAKER_01 43:03

And also the other thing that could be happening, especially if you are resistance training, and particularly if you are newer to lifting weights or maybe newer to pushing with high effort in the gym, you could be experiencing what's called body recomposition or recomp, which is when you're simultaneously losing body fat and gaining muscle at the same time. If that is happening, that can be reflected by a net zero change in scale weight. And sometimes this does happen. Sometimes the scale weight actually goes up, but you are getting leaner over time. So that can also happen technically.

SPEAKER_00 43:35

And it's also worth pointing out that when people exercise more, it is common for people to get hungrier. So it doesn't necessarily mean that when you start running, you suddenly feel ravenous and there is a huge increase in your energy intake. But you might find that you're a little bit more snack curious as the day goes on and a little bit can um kind of creep up and and Do things to your weight that you weren't realizing. Right. So I I think that's an example where someone starts exercising more, they feel slightly hungrier, they might increase their food intake 10% more than they realize just because it's easier to have an extra portion of food every so often. And you know, that can make a difference.

SPEAKER_01 44:20

Q my marathon prep and the fact that I would gain weight every time I would at the I would be at the peak of my marathon training. When my mileage was the highest.

SPEAKER_00 44:28

I actually gained weight for marathon prep as well. Yeah. I know part of that is you are intentionally eating to fuel, but a lot of it is also I remember finishing a day and being so tired and being so hungry that I'll just be like.

SPEAKER_01 44:40

You eat a huge plate of food.

SPEAKER_00 44:41

Yeah.

SPEAKER_01 44:42

Yeah. Which of course goes against what people most people would expect to happen when you're doing hours and hours and hours of cardio a week. Suffice to say, all of these things are are are factors that you can address. They're fixable. Does not mean your body is broken, does not mean that there's nothing you can do, does not mean that uh your your body is in starvation mode, anything like that.

unknown 45:02

Yeah.

SPEAKER_00 45:02

So let's summarize. Claim one that starvation mode, quote unquote, is a thing, and you cannot lose fat in a calorie deficit or you gain weight in a calorie deficit is bullshit. It's important that you know that's bullshit because it makes it harder for people to have useful conversations about this topic. People are so hell-bent on disproving starvation mode that it means that they're actually missing all of these useful conversations in the middle that I think are worth having.

SPEAKER_01 45:34

And as we've gone over in some of the most extreme weight loss trials, their metabolism did adapt, but we still saw significant weight loss amongst the participants. If starvation mode were real, this would not have happened at all.

SPEAKER_00 45:47

Now the second claim that your metabolism can decrease in response to weight loss and it could, in theory, make weight loss harder, that is fine. That's totally fine. Yeah. That's legit. As long as you know that metabolic adaptation often happens in tandem with weight loss, it doesn't automatically mean, I know it sounds counterintuitive, it doesn't automatically mean that weight loss doesn't occur. It might be a byproduct of the weight loss itself rather than an obstacle that stops the weight loss. And I know that doesn't sound like it makes sense, but if you understand how it's measured and why it's measured and why some studies come up with funky numbers, hopefully it will.

SPEAKER_01 46:28

Yeah. And also, as we've gone over, once you bring up the calories back to maintenance levels, metabolism also increases again as well. So the drop in metabolism is not permanent.

SPEAKER_00 46:39

And once again, people who lose the most weight are often the people who have the highest degree of metabolic adaptation versus I can't lose weight. You measure their metabolic rate, they have the most metabolic adaptation. Yeah. So it sometimes could be seen as more of a consequence. Yeah.

SPEAKER_01 46:58

Let's wrap up with practical takeaways. What can you actually do? Now, obviously, if you are a reasonable coach, you would know that we shouldn't be advocating for extreme crash diets anyway. If your goal is intentional fat loss, we want to have a modest calorie deficit.

SPEAKER_00 47:13

I want to like double jump in here and and emphasize that because when I have talked about this in the past, a few years ago, I remember someone talking about starvation mode on social media, and I replied and said, So this isn't a thing. And it's important that you understand this isn't a thing, because if you tell people that they need to eat more food to lose weight, most of the time that's not going to give them the results they want, obviously. Doesn't mean that eating more food is always a bad idea. However, remember that. But in general, if you tell people that they need to eat more food to lose weight, that's obviously not smart. And when I talked about this and said no, starvation mode is not a thing, for example, even in these research studies where they are on very, very aggressive calorie deficits, they still lose weight. I remember people got mad at me as if they thought I was promoting that methodology. Saying that people in the Minnesota Starvation Experiment and the biggest loser trial still lost weight doesn't mean that we're saying those are smart ideas. Yeah. I hope that makes sense. We're just saying that even if you do the most ridiculous form of calorie restriction that you can think of, it does still result in weight loss. And this is seen in in many research studies where, admittedly not now, but if you rewind a few decades ago, there were various research papers where they would put people on total fast, zero calories. And we are obviously not telling people that that's a smart idea, but they did it as experiments sometimes, and in those instances, people lost weight. Yeah. So if eating no food would cause people to gain weight, those would be the studies you would see it. And that doesn't happen. Yeah. Obviously.

SPEAKER_01 48:52

Yeah. Now, alongside a modest calorie deficit, we recommend prioritizing protein and continuing to lift weights. A lot of people I've actually I heard this a number of times. Some people believe that if you want to lose weight, you only do cardio. If you want to build muscle, you only lift weights.

SPEAKER_00 49:08

I've had clients that came to me saying uh I was told at unnamed weight loss club that I shouldn't lift weights because it will slow down my weight loss. And I'm like, that's literally them admitting that holding onto muscle tissue will slow down weight loss as if it's a bad thing. Yeah. That's ridiculous. But that's what they were thinking.

SPEAKER_01 49:27

Yeah. We want to emphasize regardless of your body composition goes, you probably should be lifting weights, whether you're dieting or trying to gain muscle or trying to maintain.

SPEAKER_00 49:37

I think it's also worth pointing out that I don't think weight plateaus are something that people should fear. I think that sometimes it's a smart idea to pause where you're at, especially when so many people diet and they feel frustrated and they hate what's going on and they're getting desperate, and they will often find themselves wanting to go down unhealthy paths. If you feel like you're one of those people, perhaps pausing what you're doing might be a smart idea.

SPEAKER_01 50:08

Yeah. And you can call that a diet break where you intentionally bring your calories back up and literally take a break from your diet, but it's strategic, it's purposeful, and I think also from a lifestyle perspective as well as a mental sanity perspective, it works really well because how many of you would say, okay, yeah, it's realistic for me to diet for six months straight without without ever bringing my calories back up? You're gonna have vacations, you're gonna have travel, you're going to have times when it makes sense to loosen the reins a little bit more. So for those reasons, and also as we saw, your RMR, your resting metabolic rate, does come back up when you bring your your calories back up too. So that can help for long-term progress as well. So implement diet breaks strategically. That's another recommendation.

SPEAKER_00 50:51

And of course, it goes without saying, but exercising is good for your health and is worth doing in the long term. So it is worth disassociating from weight loss. Don't view it as a weight loss tool, view it as a health promoting tool. And what happens to your weight is uh sometimes a consequence of that, sometimes not.

SPEAKER_01 51:12

Yeah, yeah. And I mean it does help with weight loss maintenance, but there are, as you say, many other, many other health uh side effects as well. So sho you should be doing it regardless.

SPEAKER_00 51:20

Yes. So to finish, starvation mode as most people view it is total, utter bullshit. However, there are very useful conversations to be had about why dieting can get harder. And it's important that we talk about those honestly because those will be the conversations that we think you're most likely to learn from.

SPEAKER_01 51:42

Yeah. And as we've covered, there are several things you can do to mitigate a lot of the unpleasant side effects of hard dieting.

SPEAKER_00 51:49

Yes, that's the end. Hope you've enjoyed it.

unknown 51:51

Bye.