Aidan:
Welcome to the ideal nutrition podcast. My name is Aidan Muir and I’m here with my co-host Leah Heigl and this is episode 134 where we’re going to be talking about diet breaks and refeeds. So we’ll probably start by defining what both of those things are.
Leah:
So let’s start. Yep. With defining. I think this is a good place to start because if you don’t know what a refeed is versus a diet break this is not going to make any sense. So a refeed or otherwise known as a cheat meal or a cheat day typically involves, like I said, a date or a meal depending on the approach that you’re taking that is significantly higher calories than what you regularly consume throughout that kind of dieting phase. Often a refeed is also strategically higher in carbs, so not only aiming for higher calories, you’re also aiming specifically for higher carbs.
We often do prefer the term refeed day rather than cheat meal. Honestly, for me, it’s just as simple as the connotation, the idea of cheating on your diet when it’s something that’s built into the plan. I don’t know, I just don’t like it. It’s like, does it matter? Maybe not, but for me, I don’t like talking about food in that way in terms of it, viewing it as a negative thing. So a refeed works really well for me and I think you use refeed too.
That’s what a refeed day is and that can either be at maintenance or it can be a small calorie surplus again depending on on how you’re utilizing it. Diet break on the other hand instead of having this time this one meal or this one day at maintenance or a surplus it’s more of a extended or prolonged period of time where it can be anywhere from like one week all the way up to four weeks, where you’re practicing this kind of maintenance or small surplus as part of an overall fat loss phase. If you’re doing any longer than four weeks, it’s probably just a maintenance phase within that process, but a diet break can be utilised to kind of split up a longer fat loss phase.
Aidan:
So there’s many reasons why people would want to do diet breaks or refeeds. And I’m just gonna start with one of the reasons and explore that topic. So we’re gonna look at metabolism and fat loss and how refeeds and diabetics could affect that. The first kind of reason why a lot of people do refeeds or cheat meals is because of the belief that it could spike your metabolism, so to speak. And there’s many reasons why you could think that. When we look at acute or short-term measures of total daily energy expenditure or even resting metabolic rate and also hormones associated with that type of stuff, we actually do see pretty big spikes when people do these larger refeeds or cheatmeals.
The issue with that though is it’s just too short term and doesn’t really influence things that much over the course of a week. It affects it for that day, but like three days later, the impact’s kind of gone. Whereas when we’re thinking about like spiking the metabolism or whatever, we kind of think about it having a bit of a longer term effect. And also it’s harder to justify when you think about it being like, you’ve had a massive increase in energy intake or even a smaller increase, doesn’t really matter, right?
But like you have an increase in energy intake that doesn’t have a longer term impact and it’s probably unlikely to outweigh the actual increase in energy intake. We have diet breaks, it’s a bit more complex. There likely is some form of impact on metabolic rate but it is a bit more nuanced. So what we’re gonna do is we’re gonna go through three studies on this topic. So we’re gonna talk about the Matador trial, which was a two weeks on two weeks off style trial that went for 30 weeks in the group that was doing two weeks on two weeks off or 16 weeks in the group that was just dieting for 16 weeks straight.
This really kicks things off as one of the first studies on diet breaks, probably the first study on diet breaks. With all of these studies, you can just look in the show notes, of course, like they’re all gonna be listed there if you wanna read this yourself. But this first study, greater weight loss was achieved in the diet break group and energy expenditure remained higher. This is part of why a lot of interest was gained in this space. There’s some pretty big caveats though.
Firstly, the obvious one, 30 weeks is a lot longer than 16. Double the time, or worse. Yeah. It’s hugely prolonging the process and that might not be a trade off that’s worthwhile for you individually. The second one is that it was an outpatient type study where the participants might’ve just lost more weight just due to sticking to the plan better. They were in control of these kinds of things, which isn’t a full criticism of diet breaks because it’s like, that’s not a bad thing if you stick to the plan better.
But if we’re looking at fat loss or energy expenditure, that is a bit of a criticism. Although one thing, drawing back on what I said earlier, energy expenditure did remain higher, which wouldn’t be explainable by that whole sticking to the diet a bit better thing. The second one we’ll talk about, the ICESCAP trial. This one solved the first problem, because it was three weeks on, one week off for 15 weeks, versus just dieting for 12 weeks straight. So that’s not that much of an increase in total time commitment.
But one big issue is that fat loss came out the same and there was no difference in metabolic adaptation that was observed. A few thoughts, maybe one week is just too short to see much of a change. You could also look at that being like it was only three weeks out of 15. That’s a pretty small percentage. It’s also just one study. To the best of knowledge, we only have one study in that type of format. If we had like five studies in that type of format, I would be like, okay, it’s probably not much change. But what if the second study that came out in that kind of format did show a change? Then maybe I’d have a separate opinion. So it is just one study.
But then the third one that is not directly on diet breaks, it ties into this pretty well, is titled, metabolic adaptation is an illusion only present when participants are in negative energy balance.
Leah:
Is that the name of the paper?
Aidan:
That’s the name of the paper. It’s a pretty provocative title and it actually annoys me a little bit because it kind of ties in with our actual understanding of metabolic adaptation. So to call metabolic adaptation illusion and then to have a study talking about metabolic adaptation, like, I don’t know, I don’t want to get too deep into that. But basically what the study found was that after finishing a dieting phase, when they went to remeasure metabolic adaptation at the four week mark at maintenance calories, they could barely measure it. It was pretty much completely offset after that timeframe.
So it kind of tells you that in a lot of cases, just four weeks of maintenance and metabolic adaptation is probably no longer really that present, which therefore ties into the whole diet break thing being like, if we only had those three studies to go on, you’d be like, okay, maybe one week’s not enough.
Two weeks on, two weeks off, like that’s just prolonging the process massively, but like you could say maybe it helps energy expenditure stay higher. Four weeks of maintenance, and you can barely measure metabolic adaptation anymore because it’s so little. You can see that spending some time at maintenance for a longer period of time does reverse metabolic adaptation and could play a role in all of this.
Leah:
Yeah, and outside of metabolic adaptation, something to talk about in regards to comparing diet breaks versus refeeds would just be appetite management as well. So going back to the ICESCAP trial, so outside of the metabolic adaptation stuff, that trial did show that participants that dieted for that 12 weeks straight without any breaks in between had a huge increase in hunger and desire to eat. So the diet break group barely had an increase, yet the ones that didn’t have a diet break or diet breaks throughout their hunger cues just continued to elevate throughout the process and their desire to eat by the end was quite huge. So both groups lost a very similar amount of body fat, but the, guess getting from point A to point B, potentially a lot easier for the diet break group because of this impact on desire to eat and hunger in general.
A big reason why I like to use diet breaks really is outside of that metabolic adaptation and practice. Like that’s something that I’m like, that’s a win if we do it for long enough. But I find the biggest win for my clients is the fact that they are less hungry and less miserable if they are to take a diet break throughout a longer process of dieting. Refeeds on the other hand, likely don’t have as much of an impact here. So we know that like refeeds seem to be too acute to really have that huge impact on hunger cues and desire to eat in that kind of longer timeframe, particularly because things kind of, they have to balance out.
So if you’re having more calories, let’s say on a Saturday where you’re having your refeed day or refeed meal, that means you have to have less calories throughout the rest of the week to make up for the fact you’re having more calories on that day. So are we just creating more hunger on the other days to then have that one day where maybe you do feel more satiated? It’s not like a complete reason to not use refeeds. There’s still, I have clients that like to have a refeed day, but comparing it to diet breaks, I think diet breaks are definitely more effective when it comes to appetite management over that kind of longer fat loss phase.
Aidan:
One of the things from the ICESCAP trial that chart that when they’re looking at their appetite and desire to eat. There’s a few things that I take away from that specific, like the results in that specific study was that they started out of out of a hundred in terms of their appetite and desire to eat. They started at about 20 out of a hundred in terms of how hungry and how much desire to eat. And the people in the group that dieted just straight for 12 weeks ended at 60 out of a hundred. And it was a pretty linear line. And I think there’s so much you can take away from that because it’s like what if you wanted to diet for 20 weeks? Does it continue increasing further from there?
There’s one, a lot of people hear me say that and sometimes they’ll be like, no, I’ve never experienced that. And I can think of many explanations to that. One, individual variation, like that’s always a factor. Two, were these participants in this study pretty locked in because they were in a study and were actually in a deficit for pretty much the entire time? Whereas how many people in the real world actually stay in a deficit, every day for 12 weeks. It’s pretty, it is pretty rare in the real world to actually do that, which actually could be a bit of a factor as to why these results were so huge. But I do think about that being like, if you’re committing to being super consistent in a deficit for a really long period of time, is this a problem that you will eventually face at some stage?
Onto another topic. So looking at lean mass retention, this is one that particularly in the bodybuilding world, is a big factor that is why a lot of people do refeeds or diet breaks. So firstly, looking at research just on refeeds, they don’t really have support suggesting that they will help with lean mass retention. But taking a moment here and just using our brains for a second, there is one practical argument, there’s probably more, right? But like one practical argument that stands out to me is that maybe they could help in certain cases. For example, if somebody is in a bodybuilding prep, they’re on relatively low calories, they’re struggling, they might wanna chuck a bit more calories on their leg day, which is like the most brutal session of the week.
That lets them get them through that leg day. Maybe they retain more quad, hamstring, glute, et cetera, mass because of doing that and having better sessions. That doesn’t seem too unreasonable to me. Another one that people suggest is for certain lagging muscle groups potentially doing it for that as well. So there’s many ways you could look at that as potentially playing a role. wouldn’t rule that stuff out.
One study that was a bit more promising on this topic and did make waves in 2020 was a two-day refeed study from Bill Campbell and other researchers. He’s got a pretty great reputation in the research world in this space. And they compared a 25% calorie deficit seven days per week versus a 35% calorie deficit five days per week with two days at maintenance, which is basically that kind of thing that you touched on about being like, you want everything to balance out. You have to have more of a deficit on the non-refeed days. This study went for seven weeks.
The refeed group at the end of this fat loss phase retained more lean mass with 0.5 kilos loss of lean mass versus 1.5 kilos. You could look at that a few ways. If you looked at that as percentages, it’s like this group only lost 33% of what the other group lost in terms of lean mass. That looks huge. If you look at the absolute amount, the absolute amount’s nothing crazy. It’s not actually a big difference, but it’s enough that it’s like, hey, I might take some notice of this. The next thing though is one proposed issue that a lot of people pointed out is that the measurements were taken two days after the last refeed in the refeed group, which had retained more lean mass. Lean mass isn’t just muscle mass. It’s made up of muscle, water, glycogen, bone, etc.
But the water and glycogen and also the food weight is the thing that we really want to touch on here about being like, if you did have a refeed day and that massively jumped up your lean mass. And then two days later, they did the testing. There’s an argument that maybe there’s almost a kilo of difference just from that alone.
Leah:
It’s kind of comparing apples and oranges at that point. A little bit.
Aidan:
A little bit. So with diet breaks, it’s hard to say. To be honest, pretty, it’s pretty likely that it does help with lean mass retention, but not because of the magic of diet breaks, but more because let’s use that metadata study as an example. If you took 30 weeks to lose the same amount of, in that case, they did lose more weight, but if you took 30 weeks to lose the exact same amount of weight as another group that did it in 16, you should retain more lean mass. In that particular study, they didn’t have a big resistance training protocol or whatever, but if you got somebody who was a recreational bodybuilder and they took 30 weeks to do something that another person did in 16, they now have 30 weeks of training and high protein intake and doing all these things that they should have more lean mass retention.
That’s not about the magic of diet breaks because you could also just be like, well, what if you just did 16 weeks of straight dieting and then you either spent the rest of time at maintenance or in a surplus, would you have the same results or better results in the latter scenario anyway? But it’s once again, it’s not comparing apples to apples. It’s like apples to oranges in a way because the duration ended up being so different. Rather than the magic of diet breaks there.
Leah:
Yeah. Love that summary.
The next aspect we’re going to talk about in regards to comparing refeeds and diet breaks is just like the mental and psychological perspective of all this and I guess pros and cons of both. So we’ll touch on refeeds first. So I think the biggest draw to refeeds really comes from the flexibility that it can add into your week during a dieting phase. Like a refeed could mean that you can go out socially once a week. It could mean that you are able to enjoy foods that you wouldn’t have really been able to fit into your nutrition plan throughout the week or otherwise. So it can add a lot more food flexibility that I think a lot of people do look forward to and maybe even increases the motivation to kind of get through the week and like, I seem to make it to my structured refeed and then, you know, I’ll be good. So I think it definitely has the positive of adding in that flexibility.
From a negative point of view, I think this can also be, it can almost associate like you quote on quote sticking to your diet as being like the good thing and then the treat meal or the refeed being like the bad thing that you’re doing, like a bit of a cheeky meal on the weekend or something. I don’t think they’re always like from a psychological point of view going to be beneficial for everybody. There’s also that kind of like restricting binge mentality that may come along with this type of structure I think that’s less so for things like like bodybuilding where it is quite structured. But if you just have someone that is like dieting throughout the week, they’re being very very strict and then they’re just like going gung-ho on a meal on the weekend it could create this kind of issue with restricted binge cycling so definitely pros and cons. I think there is good ways to use it, there’s less ideal ways to use a refeed or a quote on quote cheat meal.
Diet breaks so talking about diet breaks and the mental and psychological perspective there. I love that diet breaks can be set up in advance to allow people to know when the finish line is or at least when they’re going to be able to have like a decent break from dieting. So something that that I like to use is like maybe we do.
Four to six weeks on and then we have one to two weeks diet break and then we had that set up So that person is like, yep I just need to push hard for this period of time and then I get my maintenance break for a couple of weeks where I can be a little bit more flexible with food and have the ability to push my training hard and feel good and the the deficit is like the shorter period of time even if we do it in several blocks.
The other perspective is it also gives people a chance to practice, quote on quote, maintenance, which can be relevant to a lot of people who are looking to reduce their body weight significantly and then having a big emphasis on maintaining that long-term. They then throughout that dieting process, get multiple opportunities to practice what sustainable maintenance would look like and what it is, what is required to maintain that newer body weight throughout the process.
A couple of other, I guess, pros would be that you can time diet breaks with things like holidays or events or things like that where you want to have a little bit more flexibility within your food while still moving towards your goal. One downside I do see of diet breaks is potentially that it can break your momentum. If you’ve got like a really good thing going and you’re like, yep, I’ve got my system, I’m losing body weight at a rate that I really like, things aren’t too hard, then switching to a diet break phase might seem annoying, irrelevant, breaking that momentum, you might find it hard to go back.
Another caveat there is though that it’s probably useful to practice being able to be switching back and forth between a maintenance phase and a deficit phase. That in itself is probably a skill worth having. But I do find with some clients I’m like, well, we said we’d do a diet break at this point, but I really think it’s going to break some really cool momentum that we have that we’ve just like gotten. So yeah, that can be the downside of it, I suppose.
Aidan:
Yeah. And pretty much everything you said throughout both of those like refeed and diet break things like sums up a lot of my thoughts. So I will only add my two cents in that last thing as well, because it’s like, it’s a challenge that like both of us are faced about being like, clients killing it. Like, let’s just let them run. Like, let’s not break momentum. And particularly when I first used diet breaks with clients, I had really positive experiences for my first like 10 times. And then on my 11th, that did happen.
And somebody like, they really struggled to get back into a deficit after the maintenance phase. And I thought about that a lot being like, do like, I don’t like breaking people’s momentum. And I think it just becomes a very case by case thing. But the longer I’ve thought about that, with that kind of scenario, is the more I have latched onto that thing about being like, no, it is worthwhile skill having the ability to be able to switch phases. And something that made me even more passionate about thinking that that skill matters is something that’s a bit too deep for this podcast, like there’s a weight loss, maintenance is hard. Somewhere along the lines of 80 to 95% of people who lose weight at a population level regain weight. It’s a very common set that gets chucked out there.
And I kind of see it as even just from an ethical perspective being like, if we’re trying to help somebody lose weight, we need to really smash those numbers. We need to do a lot better than those numbers. Cause at some point, like if it was 95%, is it ethical to try and help somebody lose weight? Cause you’re kind of setting them up to go through the whole frustration of going back in the other direction. So we need to do a lot better than those numbers, even just to make it even become an ethical kind of discussion.
So one of the things just from a research, cause I try to be evidence -based where possible, a research perspective is it’s like, what do the people who lose and maintain weight for greater than five years, what do they have in common? And there’s many, many things that they have in common. Like they exercise consistently. Often they have decent protein intake, they have a decent fibre intake, fruits, vegetables, and water. Like there’s a bunch of things, right? They get decent sleep. But one thing that stands out to me with this whole ability to be able to switch phases is that a lot of them have what has been termed in the research, a relapse plan.
I wish I had a better way of saying it than a relapse plan, but that’s what’s been used in the research and that’s what I’ve gone with to this day, where they have a bit of a trigger point, which is like, let’s use an example. Say somebody at the end of their weight loss phase is X kilos, their trigger point should be high enough above X that if they regain like two kilos, they don’t freak out. Cause they’re like, what if that’s water weight? What if that’s a bad weekend? What if that’s more carbs? What if that’s whatever? But let’s say it’s like four kilos above, then they’re like, okay, this isn’t waterweight, like if I’m going back the other direction.
That’s where they hit that trigger point and they have a real-life plan which is like, what should I do now? And in most cases, what they should do now is kind of what worked in the first place. They should do what got them down in the first place because we often have shiny object syndrome, which is like, we try and do something differently, but it’s like, no, hang on. Like if you did something that got you down there and then you maintained for an extended period of time and then you regained, it wasn’t an issue of what you did on the way down. It was what happened when you regained, like that was the thing.
So you don’t need to change the first part, right? In that case, it would be very different if you went down and then went straight back straight away. But the relapse plan thing is a skill that people kind of need to have because if we look at over a five-plus year period, most people at some stage unintentionally gain more than a few kilos at some stage over a five-plus year period and kind of need a strategy in place to be able to handle that, which is why I think, although the momentum thing is super important, the ability to change phases is also important. Both things kind of matter.
Leah:
Yeah. And I think it’s also between your maintenance phase and your fat loss phase. I think the people that struggle to switch between them in the maintenance phase are dropping off things they potentially shouldn’t. So things like exercise and like, guess like all those, like hydration, all those boxes they should be ticking for sustainable weight loss because it’s not fun in that they’re not like losing weight. It’s just the motivation to do that drops off. So I think that probably plays a role in why people struggle to switch in between.
Aidan:
Cool. So now doing a little bit of a summary. So there’s pros and cons to both diet breaks and refeeds. I think the biggest thing is like one, the upshot management is one of the biggest pros of the diet break plus also all the psychological and also practicing maintenance thing is like very relevant to the diet break stuff. The psychological thing can be a benefit for some people for the refeeds. It might be detrimental for other things, but it’s a very case by case basis. One of the other downsides just touching on with the diet breaks is the obvious thing about like it adds time onto the journey as well. So everything needs to be weighed up about whether this is beneficial for you and your specific circumstances.
Leah:
This has been episode 134 of the Ideal Nutrition Podcast. If you haven’t yet left a rating or review, it would be so greatly appreciated for you to do so. But otherwise, thanks for tuning in.