Popular claims about diet breaks that are WRONG

Philip Pape 0:00

You've probably heard that if you take a diet break, you'll lose more fat than if you dieted straight through, and that a couple weeks of maintenance will get your metabolism going again. That is not what happens. Today I'm gonna tell you where those ideas came from, what a diet break can actually do for you, which is worth doing, and how to use a diet break so it doesn't turn into two weeks of uninhibited eating and actually benefits you for fat loss. Welcome to Wits and Weights, the show that puts a popular piece of fitness advice under the microscope, finds the hidden reason it doesn't work, and gives you the deceptively simple fix that does. I'm your host, certified nutrition coach, Philip Pape. And a couple of episodes back, on episode 501, I looked at the idea that perimenopause is what's causing your weight gain. And today it's kind of a similar thing, except this time the claim isn't about your body. It's about a specific strategy. And it's a strategy a lot of people talk about, a lot of really smart people in the space are using and repeating. And I want to kind of separate something out right here at the beginning because on episode 493, I talked about what happens when a diet ends and how you come out of it. Uh, that is a different question. Today we're actually talking about interrupting a diet in the middle on purpose while you're still trying to lose fat. And I know some of you are like, yeah, okay, diet break. A lot of you are like, Well, I didn't realize that's even a thing I could do, right? I'm trying to lose fat, so it's this contiguous thing until I get to my goal. But this is where strategy can be very helpful. This really matters a lot more for you than it does the average person, especially if you're over 40, because you've probably been dieting in some form on or off for a while. And I'll just leave it at that for a while. Like some of you have been doing this since the 90s, since Weight Watchers, South Beach, whatever it was. So the idea of stopping your fat loss mid-cycle, like what's the benefit? Okay, we're gonna get into that today. And then at the stick around to the end of the episode because I'm going to talk about the things that change when you take a break, like the scale and what to expect, especially if you're lifting, so that you don't freak out and you understand how to measure, hey, this thing is actually working. So for today's episode, we're going to first talk about where diet break advice originally came from. And there are kind of three separate things that get combined together into one claim when I hear this. Second, what happened when researchers looked at all the trials related to diet breaks? What did what does that tell us? And then third, what does a diet break actually do for you? And I actually think it's underrated. And as always, we are gonna give you the fix, which is gonna be six specific things. These are not complicated, these are simple things that can fix it so that you get the most out of diet breaks. So you've probably heard that if you diet straight through without a break, your metabolism starts to adapt, it adapts downward, and eventually you hit a stall, right? You might hit a plateau. But if you break your diet up or if you eat by eating at maintenance for a couple weeks in the middle of a diet, you can keep your metabolism from adapting as much and therefore lose more fat over the whole thing, right? Because then you can induce the bigger calorie deficit like you intended instead of uh eating the same food and having a smaller deficit, right? That's part of the logic. And therefore you could have essentially less dieting and the same or more results. And it's very appealing. Okay. It's like, yeah, we always want things for less of the hard part. And so I want to look at the recent history of this starting around 2018. And the first piece of history is Lyle McDonald, who was writing about full diet breaks back in the mid-2000s before a lot of these trials existed. And his argument is around leptin, thyroid, the uh psychological load, I guess, the mental load of a long diet, things like that. And he was reasoning a lot through a lot of this, also anecdotally, because it's what we see in people. And we hadn't yet studied it. The second one is the metabolic adaptation research, where when you lose weight, your resting metabolic rate drops more than your new body size would predict. By that I mean when you lose weight, your metabolism should drop, but also it seems to drop more than that. And when we look at controlled feeding studies, the average drop is around 120 calories a day, huge spread from one person to another. And that's metabolic adaptation. But it still doesn't tell you about diet breaks and how that could affect it. Okay. Then the third one here is a study that a lot more people talked about regarding intervals and breaks. And that was the Matabdor trial in Australia in 2018, where they took 51 men with obesity. One group dieted straight through while the other one did two weeks on, two weeks at maintenance, and they went back and forth. And they were both in like a 33% deficit. All their foods were, uh all their meals were cooked for them by a kitchen, like associated with the researchers. The intermittent group lost 12.3 kilos of fat compared to eight in the continuous dieting group. And so if you hear somebody say, Yeah, you can lose 50% more fat, it may come from that study. Now it's a good study, tightly controlled. I'm not gonna knock the study, but I think there's a design detail that affects how we interpret the result. Both groups completed 16 weeks of calorie restriction. So let me say that again. Both groups completed 16 full weeks of calorie restriction. It's just that the intermittent group, that was two on, two off, they needed 30 weeks on the calendar to get 16 weeks of dieting because of all the stops. So, really, the study showed that you get more fat loss per week of dieting, but not that you get more fat loss per month of your life or per week of calendar. So that what we call touch time, right? In um in engineering, which I know the person again listening on Spotify who doesn't like that I mention that, we call it touch time versus continuous time or calendar time, I should say. So we care about the calendar oftentimes. And if you're dieting on and off and that helps you get through the diet and it takes twice as long, you might be perfectly fine with that, actually. In fact, that might exactly be the advantage of it. The other thing is that the continuous group, their fat loss flattened out around week 12, which is often what happens when people are adapting and their deficit gets smaller and smaller toward zero. So even that efficiency difference might be a result of adherence and not a metabolism result, you know, for the intermittent group. All right. So that's where we get some of this advice from.

Analysis of diet break research

Philip Pape 6:38

Now, what what is the best data we have right now? Well, the first one is a meta-analysis and nutrition reviews by Poon and colleagues. This was 12 randomized trials, 881 participants. And the way they set it up is pretty good. They only included actual diet breaks and refeeds. So these were periods at maintenance calories. Okay. They didn't in they didn't have intermittent fasting, alternate day fasting, time-restricted feeding, all that stuff. That's a different intervention. They just did the diet breaks and refeeds. The between group difference in body mass was almost zero, 0.01 kilograms. So that's like basically nothing happened. There was no difference in fat mass between the control group and the group that had the diet breaks, no difference in lean mass either. All right. And it wasn't a small study, right? Almost a thousand people. It's pretty good. The second study is from the Jeb group at Oxford, published in Obesity last year. And there were nine intervention arms with almost 800 participants. 77% of them were women, which we we don't often see. Right. Usually it's split or it's men. The difference in weight change for them was 0.09 kilograms. They also checked the dropout rate, right? The whole promise of a diet break is it makes your diet easier to stick to. So it should show up in a study as fewer people quitting. But it didn't. There wasn't any difference in attrition in the participants. Okay, so two different research groups, different countries, different rules, different methodologies, the same result. That is, diet breaks do not produce more fat loss. Now, one thing did change, right? I don't want to ignore this. That's resting metabolic rate. In the pool trials, the continuous dieters dropped their resting metabolic rate by about 92 calories a day, whereas the group taking breaks dropped it by only 39 calories a day. Now, it wasn't statistically significant on its own, right? And the difference was 47 calories, but we've seen this sometimes across other studies. So 47 calories a day difference is basically the case you can make from a physiological

The one thing a diet break DOES help with

Philip Pape 8:40

perspective for diet breaks, that you would not have your metabolism drop as much by about 47 calories a day. Which again, you could argue is that something or is that not much of anything? When you split it by population, it looks like the the amount of metabolism protected was about 73 calories a day in people with overweight and obesity, about 11 calories a day in resistance trained people. So the more lean and trained you are, the smaller it got. So that kind of confounds the data as well. Now, here's a part I actually find more interesting. Okay, a little bit of a tangent, but stay with me. I think it's important. The whole diet break argument is aimed at your metabolism, at your resting metabolic rate for the most part, right? There's the psychological piece, of course, we're going to cover, but most of the argument made is about physiology. And that is not where most of the metabolic adaptation happens anyway. Most of what we see when people lose weight and we measure total daily energy expenditure is predicted by non-resting energy expenditure. So that's your movement, how much you fidget, how fast you walk, whether you take the stairs, whether you're doing the dishes, standing up or sitting down, all that stuff, right? A lot of it, which is unconscious. We talk about this often, how when you go into a fat loss phase, oftentimes you move less without even realizing, even though you're trying to compensate by more steps, for example. And then that component of your metabolism then drops proportionally with how much weight you've lost as well. And that part is bigger than the resting part that changes your metabolism. So if you become a smaller and less moving person over several months of dieting, that is not gonna get fixed by a diet break, right? You can eat at maintenance for a couple weeks and you're still probably at the same activity level, this lower activity level than you were. And of course, you've you've lost that weight. So it doesn't help from a metabolism standpoint.

Setting up your own refeed or diet break the right way

Philip Pape 10:28

All right. So if you're thinking, how do I use a diet break properly? Because we're gonna get into the fix, but I always like to give you a practical way to do it to follow along. When do I take it? How many calories? What do I do with my carbs? All that stuff, which we're not gonna get into on today's show. I have a free guide on that. It's called Fat Loss Refeeds, the Fat Loss Refeeds Guide. Go to link in the show notes or go to wits and weights.com slash free. It covers refeeds and diet breaks during a fat loss phase, how to set the calories, how to handle your hunger, how to keep your perform performance up in the gym. Totally free. Okay. Go to wits and weights.com slash free. You might even want to get it right now. Pause the episode if you can and kind of follow along with what I'm talking about here and be like, okay, now I see what you're getting at. Wits and weights.com slash free or use the link in the show notes for my fat loss free feeds, guys. Again, link is in the show notes, witsight and weights.com slash free. Okay, so if it doesn't help with fat loss and it doesn't help with your metabolism, why do I still use diet breaks all the time? Why do I love diet breaks, actually? Me personally, Philip, those of the show. And why do we have it and eat more lift heavy? And why does my app recommend diet breaks? And why do really smart people recommend them? Well, let's look at a very recent trial in Nutrients, the journal Nutrients. They took 30 women with obesity, 12 weeks, both using a 25% deficit. One group dieted straight through continuously, the other one did a refeed day every week, plus two full seven-day diet breaks in weeks five and week 10. Okay, got it? So you had a continuous group and you had one that did single-day refeeds and week-long diet breaks. The diet break group was essentially dieting only 71% of the time. The fat loss came in at 9.3 kilos in the continuous and 9.2 in the break. So they were the same fat loss. If anything, tiny bit less in the diet break group. Okay. But if you look at what the diet break group had to do to get that result, their measured deficit was 690 calories a day. The continuous group was 1,005 calories a day. That's the average, right? And that was statistically significant. So the continuous group had to diet harder and longer, essentially, to get the same fat loss. And remember, both groups lost the same amount. It's just that the intermittent group didn't have to be dieting as much. And we see a same direction for the adherence. Dietary adherence was 91.4% in the diet break group versus slightly less at 88.4% in the continuous group. Same thing with protein compliance, 93 versus 87.9%. Hitting their calorie target, 89% versus 85%. All of these lean in the same direction. So the case for a diet break is the same fat loss, but less time under that calorie restriction and slightly better compliance while you're doing it. So for somebody who's been dieting on and off for 20 years, like you, dear listener, probably, I'd argue that that is worth a lot more than any the other claim about like it affecting your metabolism anyway, or trying to gain more some extra advantage of fat. This to me is an advantage, the ability to do it. Now, Dr. Bill Campbell is on the author list. So whether you consider that a conflict or not, I don't. Great guy at a University of South Florida. And back in 2020, Campbell published a refeed study in resistance trained people that concluded the refeed preserved fat-free mass and resting metabolic rate. But then Payos and colleagues published a comment to that paper showing that on reanalysis, only the dry fat-free mass differed. There was no difference in total fat-free mass and none in the resting metabolic rate. And then Campbell published a reply saying, Yeah, I agree. So, which I wanted to mention that because that's a good example of science out in the open working the way it's supposed to do. So I'm not going to claim that a refeed can preserve muscle either. All right. Now, there is also a trial in resistance trained women

The only diet break study run in postmenopausal women

Philip Pape 14:20

from Seedler and Colleagues, where they had 38 women for six weeks using a 25% calorie deficit. And they found no difference in body composition, no difference in resting metabolic rate, no difference in seven of eight eating behavior measures, hunger restraint, all of that. The one thing that changed was disinhibition on a validated eating questionnaire, which got better in the diet break group and worse in the continuous group. So that is consistent with the story on adherence, that it is easier to stick to the diet when you have breaks. And the average age in that study, to be fair, was only 22, which again, a lot of these studies are hey, we're gonna pay you some money to do in this study while you're in college, stuff like that. The only diet break trial I could find that was run in post-menopausal women is a small pilot from 2012. They had 25 women with obesity and they did three blocks of restriction separated by five-week maintenance periods. And the intermittent group lost more lean body mass than the continuous group. So that was that's in the direction we don't like. But again, that's 25 people, women with obesity, not lifting, small pilot study, right? Sedentary women. So hard to really pull anything from that, but I always do like to say, hey, what other studies can I find out there? I'm not gonna put too much into that one. But I think the idea that taking a break helps you stick to your diet makes a lot of sense, doesn't it? So what is the fix?

The 6-part fix for taking a dieting break

Philip Pape 15:49

All right. Well, there's six things. Simple, not always easy. Number one, you decide what the break is for before you take it. If the reason is I'm gonna lose more fat, don't take it because you're not. You'll be disappointed. You're gonna blame your metabolism, all that jazz. If the reason is, hey, I've been at this for 10 weeks and I'm really struggling to do it now, I'm struggling to be consistent. Great time for a diet break. It's kind of like taking a D load with your training. Too much fatigue. Okay. That's number one. Number two, take it based on an if-then trigger that you plan for in advance. Does this sound familiar to you? This is a strategy we talked about on a recent episode, episode 499. So go check that out. I'm not gonna kind of reteach the whole method. Go episode 499. We talked about having if-then strategies as one of the skills. The short version is if you wait until you feel like you need a break, then you're deciding at the wrong time. You're probably hungry and tired and annoyed, emotionally distraught. And that's the worst possible time to make a decision. So even though number one was decide what it's for, number two is decide ahead of time when you will take it because of number one. Does that make sense? Like plan for it ahead of time. And for a lot of people, this could be if then, as well as like once it's been five weeks, I'm just gonna take one. Because you know at that point it's gonna start to get tough. Five, every, every six weeks or something. Number three, a lot of people get this one wrong. You do the diet break at actual maintenance. What does that mean? I mean you have to be tracking your numbers so you know what your maintenance calories are right now at this point in your diet. And then not just like listen to my body, not I'm gonna eat intuitively for two weeks, because that's where people go wrong. So for a lot of people, you're probably in like a 300 or 500, maybe a 700 calorie deficit, and you're essentially bringing those calories back in and making sure you really get the full recovery, but also not eating ad libitum as they say, like whatever the heck you want, and potentially far overconsuming and really going against yourself when it comes to fat loss, right? And when you take a break, that number has to be right. You've heard me talk about macrofactor. We use it all the time because it helps you track your expenditure and you know what where that number is. I'm an affiliate, full disclosure. If you want to support the podcast, go grab the app, macrofactor, use my code WITS and weights. But the reason I like for it is like the app is it works out your expenditure based on your weight and calorie intake. And so when you're gonna take a break, you just go right up to that number it currently says you're burning into by increasing carbs. Number four, a diet break is one to two weeks and then it's done. You don't need to go longer than that. If you do, that's more of a maintenance phase. Perfectly fine thing to do, but it's a different decision with a different purpose. Number five, protein, protein, protein stays the same. You don't change that. But what you're gonna do is you're gonna increase mostly carbs. And number six, you keep lifting like normal right through the diet break. In fact, a deload is a great thing to have at the same time as a diet break. Don't force it, but a lot of people do the opposite. They'll take a deload and then they'll like, they're like, well, I'm not training as hard, so I shouldn't eat as much. Do the opposite. You're trying to recover. If you're not training, if you're taking a break from your diet, your training, you need to take a break from your dieting and eat more. Not you don't need to, but I'm saying they go well together, right? So you so you always have to be lifting. Now, I know I kind of rambled through a bunch of different studies and hopefully I didn't lose you guys, but really what I'm saying here is diet breaks can be very useful. It's very useful. But the reason they're useful is because of adherence and pretty much just because of that. Not because of fat loss, not because of maintenance metabolism, not because of muscle preservation necessarily. Now, if you find that it helps those things for you, awesome. Again, the science just seems mixed at this point. I'm not saying metabolic adaptation doesn't happen either, because it does happen, right? We know that happens, but the diet break isn't going to resolve that. You should take a diet break because you need the relief and you'll be better at sticking with your diet afterward. That's it. Very powerful tool for that purpose. And a lot of you aren't even doing it for that reason. You you're stubborn, I'll be honest. And you want to get the result, you want to get that fat loss. You're like, I can't slow down. But by continuing, when you actually need a break, you end up the wheels fall off. You end up getting more and more inconsistent, you don't get through it all, you get frustrated, and you don't get to your goal anyway. So very much consider diet breaks.

Bonus: how to interpret scale weight changes during a break (and not freaking out over it)

Philip Pape 19:56

Now, before we wrap up, I told you at the top I had a number to share with you about how the scale changes during a break and people who lift. I'll give you that in a second. But if this changed how you are thinking about your current phase, go get my free fat loss refeeds guide I mentioned earlier. Go to winsoweights.com slash free or use the link in the show notes. If you know anybody else who's big into dieting and you think, hey, maybe they would benefit from learning about diet breaks, send it, send them this episode as well. All right, so here is a number I want you to consider before your next diet break so that you are prepared for it. The scale is going to move and you're going to react or freak out to it. Uh and when we look at I always like to point to studies so you understand where this is coming from. There's a trial called ICE CAP. I know. Crazy acronyms. I don't know where they get these. They had 61 resistance trained adults. They took a one-week break at maintenance in the middle of a fat loss phase. After that one week, their body weight went up about 0.6 kilograms. It's about a pound and a third. The fat-free mass measurement went up about 0.7 kilograms. Resting metabolic rate went up as well, and muscular endurance improved as well. So, what is happening? Well, your water and your glycogen is refilling here. That's all it is. Your what your fluids are refilling. So when you see that jump on the scale, okay, which could be again a pound, two pounds, sometimes three pounds, depending on how big you are, during a break. The thing to do is don't touch anything for up to a week after the break ends. Just get back to your normal deficit where you were, and the trend's gonna catch up. What you should see then when you get into this pattern of breaks is your weight's gonna go up, then it's gonna come back down. And all that is is temporary, right? You don't want to make up for it or cut extra calories and go to a bigger deficit, which has its own risks and problems and then makes your diet even harder and backfires in other ways. So that's it. That's it. Okay, until next time, keep using your wits, lifting those weights, and remember that a diet break changes how long you spend dieting and how well you hold it together while you do. It doesn't change how much fat you lose or your metabolism. I'm Philip Pape, and I'll talk to you next time here on the Wits and Weights podcast.