Episode 123 Transcript – Calorie Cycling

Cartoon of Leah Higl and Aidan Muir for the Ideal Nutrition Podcast.


Hello and 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 123 where we are going to be talking about calorie cycling. And calorie cycling, it sounds like an advanced nutrition strategy, but basically, put simply, it is just the concept of intentionally having a different amount of calories on different days.


Starting with something very, very simple. So we’re just going to summarize the different types of calorie cycling that do exist and briefly just the logic behind them before we dive into the rest.

So number one is a calorie deficit where you’re doing calorie deficit five to six days per week and then either maintenance or a surplus for like one day a week or so where it’s like a refeed or a cheat meal day with the purpose of trying to improve fat loss and we will go over that further. But that’s number one.

A secondary reason why you might do calorie cycling or how you could potentially do it is have different calories on different days just based on general training needs. So for example, having more calories on a training day and then fewer calories on a rest day could be an example of calorie cycling.

And the third way of doing it is just having different calories on certain days for general food flexibility. So a really common example of this type of calorie cycling is having a calorie deficit five days of the week and then two days of the week, like higher calories. And that’s usually over the weekend when you maybe want a bit more flexibility.


Looking at that first one, we’re going to talk about whether there are any direct advantages for fat loss. We’re going to talk about this theoretically, and then we’re also going to look at outcomes.

So if there was going to be any direct benefit for fat loss, it would have to come in the form of either changing your calories in or changing your calories out, Or, as a bit of a complex one, but like improving how much muscle you retain because if you were in a calorie deficit and losing weight but you’re holding onto more muscle, by definition you’d have to be losing more body fat in the process. So it’s got to either affect CICO, so calories in, calories out, or how much muscle you hold onto.

For the sake of this part, with the calories in calories out, we’re going to assume that calorie intake is stable. So we’re not going to talk about in terms of change that because we’ll talk about that in the food flexibility kind of section with the muscle growth aspect. We’re going to talk about that in the next thing we talk about in terms of performance and everything like that as well. So we’re going to separate that for now.

So the main thing we’re really looking at is does calorie cycling change our calories out? Like does it quote unquote spike the metabolism? And this is an interesting topic because a lot of people do cheat meals or refeeds in the bid of trying to spike their metabolism.

It kind of makes sense when we look at it from an acute perspective. If somebody is in a calorie deficit six days straight and then on a seventh day they either eat at maintenance or they eat in a surplus, we do see spikes in certain hormones. For example, leptin is a hormone that increases when we do this.

The problem with this though is it’s too acute. It’s too short term. We see a spike, but then it returns to normal. And the difference that this has over the course of a week is just too small. And it’s too small, particularly in relation to the fact that you’ve increased your calories substantially, which therefore means you’ve taken one day or two days off of being in a deficit to spike the hormones for a very short period of time, which will then return to normal. And if anything, it actually slows down your progress a little bit from that perspective.

We’ve added some studies on this concept in the show notes, both looking at the change in the hormones, but also looking at outcomes and basically showing that there’s not really a noticeable difference in metabolic rate over the course of the week. So from that perspective, in terms of the calories out, there’s not a direct advantage for fat loss.


Yeah, I think like looking at reversing metabolic adaptation, like that’s where diet breaks really come into play instead of like those acute refeeds.


Particularly longer ones, yeah.


100%. Next topic that we’re going to talk about is, are there direct advantages for performance and muscle growth or retention when we do this kind of calorie cycling. So theoretically, you could time your intake to align with certain training sessions or have like more calories on certain training days to maybe produce better performance output.

So for example, if you had one day you had a rest day, but then another day you had a two hour lower body session in the gym that was quite calorie intensive, you had a lot of output that day, adding more carbs and more calories to that specific training day as opposed to your rest day could lead to a better training session overall.

And then the improved performance in that session over time theoretically maybe could lead to like more training stimulus and then better training adaptations and potentially better outcomes. But that’s kind of just based in theory.

It also means that you don’t end up being in a big calorie surplus on your rest days. So if you’re kind of just, if you have days where you have really high energy needs and days where you have quite low energy needs and you’re just kind of doing, taking an average and then having the same calories like day in, day out, it might mean that you are more in a surplus or just having excess calories on a rest day where maybe you don’t need it. So from that perspective, you know, it can start to make a little bit of sense to trial this calorie cycling in some circumstances.

The downside of this particular logic is that it is making the assumption that improved performance in your training session does equate specifically to improve training stimulus and therefore improve general outcomes over the long term. So let’s say you do all of your sets on an RPE8, but there’s two training sessions. One session you have more glycogen in the tank. You’ve had more calories, more carbs that day. And on the other day, you’ve had just generally less.

The version with less glycogen potentially gets less reps, less volume throughout that session. But does that mean that you actually gain less muscle and less strength in the long term? Like what is the actual practical outcome over time? We kind of are just making assumptions here.


Yeah. Like it seems like a common sense thing being like, if you don’t overthink this, this should help improve outcomes. Yes. But like, if you do look at the research really closely, it’s like, it’s hard to make that claim as well.


A hundred percent. So it’s like, we are kind of just guessing at a certain point. Something also to consider here is like, everything is a trade off. So by putting more calories in your training day, you are having less calories elsewhere throughout the week.

So I think a lot of people assume that on your non -training days or your recovery days that your calorie needs are less. And I guess from a direct point of view, your output is lower. So technically, yes, directly your calorie needs are less, but calories are also required for recovery. So by taking away some of your calories from your recovery day, are you potentially reducing the amount that you are recovering and your muscles are repairing on that day?

So are you trading improved performance on one day for less recovery on another? Again, that’s like just theory. Like we’re not sure what these kinds of practical outcomes would be. But it is something to think about is like, there’s an argument on both sides to be made.


Yeah. And like I’ve sat down and thought about it and being like, what if there’s a theoretical perfectly sized calorie surplus or perfectly sized calorie deficits? Like say that perfectly sized calorie surplus was 200 calories every day.

If you just had a straight calorie intake every single day and you had rest days as well, theoretically, as you said, that means you’ve got a larger surplus on rest days and maybe a non -existent surplus on training days, depending on the size, obviously, and how much training you’re doing.

Theoretically, that kind of makes sense. That’s like, well, if you address that and you just have the perfect size surplus every day by changing your calorie intake, you would get better results. But that makes sense to me. I kind of agree with that. But one of the things that really challenges that is one, we don’t have a research supporting that concept. When we look at body composition outcomes, it doesn’t seem like it makes any difference.

And two, another kind of flaw in that is that we can’t even directly measure energy expenditure perfectly on every single day. So even if you were doing that, trying to have this perfect calorie surplus, et cetera, it still wouldn’t be perfect. Because even on different training days, you’re going to be burning different amounts of calories.

So you can’t perfectly line things up anyway. That doesn’t mean it’s a useless approach or anything like that, it’s never going to be perfect even if you try to make it perfect.


Totally and I think it definitely makes a lot more sense for athletes with really high training volumes. Like I work with a lot of Ironman athletes and like they may have a rest day where at baseline let’s say they’re burning like 2 000 calories for that day on a rest day but there’s a training day where it’s like six, seven hours of training on a long ride day or a long run day or whatever they’re doing and they’re burning like over 3000 calories that day.

It’s like, okay, then calorie cycling makes a little bit of sense for them because it’s such a large discrepancy in output. And then you take into consideration like the amount of extra calories they potentially need for like intra -training and pre -training fueling being a lot higher.


Yeah, I think it makes a lot of sense. And I just, I also will change it for those people. Although we don’t have research on that. I would love to see research on that. The other logistical challenge, as you know, as well as like, if you try to match their calories perfectly, it creates massive issues with hunger.

Like say they eat 2000 calories on rest days and they eat like six hours on a training day or whatever. On that rest day, they are starving. They are really hungry. So if I do implement concepts of this, which I do with a lot of athletes, I don’t try to match calories perfectly.


Yes, that’s such a good point.


Like maybe I’d add in that case like a thousand calories extra on training days or something like that, but it wouldn’t match it perfectly.

So now the food flexibility topic. So this is a bit of an easy one in that a lot of people not tracking or whatever unintentionally would be doing this anyway. Like there’s many people who maintain their weight year round, but eat slightly more calories on weekends than they do during the week. They wouldn’t call that calorie cycling. That’s just living life, et cetera.

But this one, if we, if somebody was tracking calories, they’re trying to make good progress, one way they could use it is either having like six days a week and one day on the weekend that’s higher, or maybe even two days and then accounting for that during the week so the average comes out the same. Or they could even think through being like, what if one random social event comes up that I just wanna eat higher calories at? If they just look at their weekly average, they can kind of make it work.

So that’s one thing. There is a gym chain I work with that created a calculator for how you could implement this that I think was a really like innovative way of doing it because using some specific numbers, if you ate 50 calories fewer for six days of the week, that gives you 300 calories extra one day. If you ate 100 calories fewer, that gives you 600 calories extra for one day.

If you thought about that and you’re like, well, 100 calories fewer per day, not that much of a sacrifice. So then suddenly have heaps of flexibility, like 600 calories of flexibility extra on one day of the weekend. You could go out to the dinner and have a drink or like whatever it is and it would fit in really comfortably and you still get pretty much exactly the same body composition results.

Where it falls apart is if this is taken to an extreme. If you do exactly what I kind of just said, you get pretty much the same results and it’s way easier from a flexibility standpoint because you don’t have to sacrifice that much. You can still do social events and stuff like that, get the same results.

But what if you ate 1000 plus extra calories over the course of two days on the weekend? That now means instead of having six days during the week to create that deficit, you only have five days to create that deficit. And suddenly the deficit’s gotta be larger. I can’t do the maths on the top of my head, but it’s like a couple hundred calories you probably have to eat less per day.

But you’re already trying to be in a deficit in this kind of example that I’ve just used, which now means five days a week you’re in a massive deficit. That creates a few problems. One, you’ll be hungrier on those days. Two, if you train hard, you’ll be under -fuelled for that training. You won’t be recovering as well. You won’t feel as good during those training sessions. You will also be consuming fewer micronutrients, so vitamins and minerals on those days.

And the further you take this, something that I don’t think people think through that clearly is by definition, it’s probably reducing dietary quality significantly over the course of a week because most of the time, if you were doing it for food flexibility, on those higher calorie days, you are adding more lower quality food, so to speak. And then during the week, you would be cutting back on higher quality foods to make room for this.

So this from a food flexibility perspective can be a really good concept if applied well, but if you take it too far, it probably causes more problems than it solves.


Yeah, definitely applying it at the extreme is definitely gonna cause issues, but I love utilizing this kind of method in its better form where you are just having a small amount of calories throughout the week and then have a little bit of extra buffer room.

Touching a little bit on the indirect benefits of calorie cycling before we do a little summary and wrap up. So twofold here, the food flexibility approach can make things so much easier to stick to for certain people. There can be such great mental benefits to just being able to go out to that social event on the weekend because you’ve had a little bit of a little bit more restriction during the week or however you choose to do it, it can just create some flexibility that in the longer term works well for you and then you’re able to stick to that calorie deficit better, so adherence is better, outcomes are better, etc.

The second point here is the added fuel on training days. So if you take the approach of having a little bit of extra fuel on training days, this can sometimes just improve how you feel in that training session. It can just improve the quality of it. And that can just feel good. So even though if we don’t have research to easily quantify this and back this up, if you feel it works for you, that is worth something in itself.


I’m really big on that feel thing. Like it’s not scientific or whatever, but that is a large factor as to why I put in a lot of athletes’ plans, like slightly more calories on training days beyond even the other theoretical stuff. Using somebody who’s a lifter as an example.

One aspect we know for sure is that a lot of people need to train relatively close to failure to get the most muscle growth, right? And let’s say you have a hard leg session and you’ve got high rep squats, for example. That’s always going to be brutal. If one version of you feels good and one version of you doesn’t, who’s more likely to get near failure? Probably the version that feels good.

And then say you have, let’s say it goes for an hour and a half or two hours. Who’s getting more reps out at the end? Probably the person who feels good. That person’s probably getting closer to failure just because they just feel better and they can train harder. And it’s very hard to quantify that stuff in research because in research, participants are forced to train near failure.

When you go to the gym by yourself, maybe if you’re not feeling it, you’re not going to go as hard kind of thing. That’s one reason why I’m really big on this feeling good.


Yeah, and I think that can be such a placebo effect to just having that little pre -training snack. Even if you don’t necessarily need it because you had plenty of carbs at lunch, I think there’s definitely just that general mental benefit to it.


For sure. This has been episode 123 of the Ideal Nutrition podcast. As always, if you could please leave a rating or review, that would be massively appreciated.