Refeeds, cycling carbs and spiking calories are all part of today’s sexiest protocols. And why not? I mean, they sound pretty cool, don’t they?
I’m sure at this point you’ve came across various dietary approaches or protocols that are non-linear in nature, through “cycling” either calories, macronutrients or both.
There are endless numbers of people who anecdotally report success on using macronutrient cycling, refeeds, fasting or simply using different calorie and macro set-ups based on whether they are training or not.
But the question I want to try to answer in this post is not whether these non-linear protocols can work or not. They do work and I’ve seen them work.
But rather I simply want to answer the question; do such non-linear protocols offer a distinct advantage over a linear dietary set-up? You know, one where you are pretty much hitting the same calories and macronutrients every day.
When it comes to body composition, does non-linear dieting really have an advantage over a standard linear diet?
First it might be useful to outline various dietary set-ups to show what we are comparing.
Simply hitting the same calorie and macronutrient targets everyday.
The idea is ridiculously simple. Essentially non-linear diets are those that have variable levels of caloric and macronutrient intake from day to day. There are endless ways to meet this criteria.
Carbohydrate Cycling – Simply varying between different level on carbohydrate intake. You could move between low, moderate and high-carbohydrate intakes on different days, as in the example in the below graph. You could be on a low-carb diet with intermittent “carb-up” days at set intervals (say weekly or bi-weekly). Hell, you could even just eat more carbs on training days and less on non-training days. Note also that you are probably “fat cycling” as the most standard approach is to move carbohydrate inversely to fat intake.
Calorie Cycling – Simply moving calorie intake up and down. This is where refeeds would fall in under. These are days during a dieting phase (hypocaloric phase) where calorie intake is increased to either maintenance level (as Eric Helms talked about in episode 28) or even pushed into a “surplus”. However, the other days calories should be lowered by a sufficient amount to account for this surplus so that the weekly average still puts the dieter in a net hypocaloric state. Example given towards the end of this post.
Protein Cycling – There are some approaches that make use of protein cycling. One example being a “protein fast”. The idea being that when you go without protein, the process of autophagy can run maximally. This process is essentially clearing up and fixing damaged cell components. Amino acid intake will inhibit this process, hence why intermittent fasting is often though of as potentially useful for cellular health.
What is a low-, moderate- or high-carb day?
This is completely subjective. There are too many variables (lean body mass, glycogen status, nature of training, goal, etc.) to take into account to give accurate figures for what constitutes each of these days. However, I tend to use the following as general starting points:
Really there is no correct or incorrect way to “do carb cycling”. All it means is that your carb intake is varying up and down.
So are you better off going linear or non-linear when dieting?
There are two perspectives we need to consider this from:
- Is there an actual metabolic advantage to non-linear dieting?
- Is there a practical, “real-world” advantage to non-linear dieting?
1) Is there a metabolic or hormonal advantage to non-linear dieting?
The first case that could be made for a non-linear dieting “metabolic advantage”, is that of the supposed benefits of a “re-feed” day. Where by the re-feed can have a positive influence on certain hormone levels. The most common ones discussed are thyroid and leptin. Let’s take a look at each of these.
Re-feeds & Thyroid Output
Active thyroid hormone, T3, is often thought of as the “metabolism hormone” since it regulates metabolism. The concept of a reduction in active thyroid hormone (T3) during dieting is not a new one. Across the board, research shows a drop in T3 when calories are restricted.
Lyle McDonald makes the point that “high blood fatty acid levels tend to impair the uptake of T4 (inactive thyroid) into the liver. There are also changes in liver metabolism that impair the conversion of T4 to T3. There is some evidence that high blood fatty acid levels causes tissues to become resistant to thyroid hormone itself (this is part of why just taking extra thyroid on a diet doesn’t fix all of the problems)”.
This state of high fatty acid blood concentration is in line with the reduced levels of insulin we would see during a calorie-deficit and/or low-carbohydrate dieting phase. So when we re-feed or break the deficit, the reverse will happen. Insulin goes up, fatty acids in the bloodstream drop and this will improve both the uptake and conversion of T4 to T3.
Of course the true question is; does this have any practical significance?
In other words, even if we get a reduced T3 level during dieting (as long as it’s not low by clinical standards) does it even matter in terms of body composition?
And perhaps even more importantly; even if there is an issue, would a one-day refeed be enough to reverse the potential reduction in fat loss ability?
Could a one-day small bump up in thyroid production due to increased calorie intake lead to a distinct change in body composition over the period of a dieting phase? I don’t know.
Re-feeds & Leptin Production
Leptin is that satiety hormone you always hear about. It should regulate body fat levels. Changes in leptin can change the feeling of hunger, as well as changing energy expenditure. As leptin is secreted from fat cells, more body fat should mean more leptin. This should lead to a decrease in appetite and increase in energy expenditure, therefore preventing us from accumulating too much body fat.
So when we go on a hypocaloric diet for a prolonged period of time, leptin levels drop. When they drop, the reverse happens. Appetite increases and energy expenditure drops. Therefore, it’s logical to assume that if we can keep leptin levels higher whilst dieting, the better off we will be. And how do you increase leptin? Increase calorie intake.
So while overfeeding on a given day will certainly raise leptin levels, the question we again need to ask is “does this have any practical significance?” In other words, even if we get a temporary elevation of leptin, does that translate to a meaningful reversal of the adaptations we get with a dieting phase?
I don’t know. There is pretty much no good quality research that I could find that answers this question. So you could make a case for yes or no, based on your personal viewpoint. The other thing to bear in mind is that leptin is certainly not the only hormone involved in the regulation of body fat levels, satiety and energy expenditure. This whole complex process of energy homeostasis has many players alongside leptin; grehlin, PYY, GLP-1, glucagon, adiponectin, glucagon and others.
Anti-Catabolic Effect of Insulin
Much is made of insulin’s role as an anabolic hormone. However, it’s probably more important to refer to it as an anti-catabolic hormone. One of it’s main roles is in preventing muscle protein breakdown.
So again, as dieting will induce lower insulin levels (especially on a lowered carbohydrate intake), we are likely to be in an overall net state of catabolism (it’s not all bad, you need to be catabolic to release fat and oxidise it remember). So one potential metabolic advantage of a calorie spike and/or a carb refeed could be to spend say a day or two per week in a more anabolic state.
This gives rise to the idea behind most common form of non-linear dieting people go through (perhaps without realising): bumping up calories and carbs on training days, and reducing them on non-training days. Idea being that you are “being more anabolic” on training days and therefore could potentially build muscle tissue on those days (or at least prevent loss) and then lose fat on rest days. Classic case of body re-composition. Martin Berkan’s Leangains protocol seems to follow this idea.
However, I’d suspect that individuals capable of “re-comping” (i.e. building muscle and losing fat during the same phase) has more to do with them using resistance training whilst being either a relatively inexperienced trainee, having an excessive amount of body fat or probably a combination of the two.
At this point you’re probably thinking “is there anything we can say for non-linear dieting?” Well, as I outlined in the above sections I think we always need to ask; what is the practical significance of doing this? So let’s forget metabolism for a moment and get into practical application. Is there a reason why we should use non-linear diets, even if there is not a metabolic advantage over linear diets?
I mean, I’ve used them. I’ve programmed various forms for a number of clients. So, what’s up with that?
2) Is there a practical advantage to non-linear dieting?
This is the area where I feel non-linear dieting can become a real asset. In certain scenarios a non-linear plan can be super effective.
Psychological Break During Hypocaloric Periods
You’re going through an extended period of dieting, trying to get down to a certain body fat percentage perhaps. Calories drop. Most likely carbs will have to drop at some point (because we all love protein too much and nobody enjoys the sex drive-killer that is a super low-fat diet). And yes, a low-calorie + low-carbohydrate diet is exactly as much fun as it sounds. IT SUCKS.
And this can be quite mentally draining for someone who is doing this for more than a week or two.
So enter a non-linear diet!
You could keep calories consistent but just cycle carbs and fat inversely. This would maintain the energy deficit, prevent someone eating low-fat everyday and then allowing them days where they can get a decent amount of carbs in, despite their caloric deficit.
Another way, one which I prefer to use (and people love it), is simply to combine a “carb-up” day with a big spike in calories too. This completely eliminates the feeling of dieting. As well as allowing the opportunity to eat those favourite foods that can be hard to fit into a calorie- and carbohydrate-restricted diet. It’s important though that the other days are reduced sufficiently in calories so that the weekly caloric intake is still on point.
Prioritization of Training Sessions
One of those big conundrums for many strength trainees is how the hell do we get lean whilst preserving (or possibly increasing) strength or gym performance. There are many limiters here, not least of which is that we’re simply taking in less energy. However, another common issue for those doing demanding training is obviously the availability of glucose whilst on a lower-carb diet.
Now the obvious solution is just don’t be on a low-carb diet right? And the linear diet in the below table shows an example. However, what if, because of the calorie restriction, we end up with a low enough carb intake that prevents adequate storage of glycogen? This will probably be only in the case of hard-charging trainees with several sessions per week. One way around it is to use a carb refeed as often as is needed to restore glycogen stores.
I’ve used cyclic carbohydrate diets with a number of strength trainees who had a priority on 1-2 of their training sessions. This would usually be something like a big squat day or the day of a lift they were focusing on at that time. In such a case, we’d have a high-carb day either the day before the session (if morning training) or the day of (if late evening session).
Social Carb-fests Needn’t be Avoided
This again touches on the psychological aspect of dieting. If we could find a way for a dieter to be able to go out of a Saturday night with their spouse (do people still use that word?), have a big dinner, a delicious cheesecake desert and perhaps a glass of red wine, then how much easier is that diet going to be to adhere to?
Is this impossible whilst on a calorie and macro-controlled diet?
Well how about just setting up the other 6 days of week so that Saturday becomes a big calorie and carb re-feed? Is it worth it? Depends on the individual. But certainly a high number will be willing to be a bit more restricted during the week if they can do this.
Getting Caught Up in the Minutiae
I’ve used pretty much all of the protocols and approaches mentioned above. I even did it all at once:
- Fasting until 1pm everyday, black coffee in the morning
- Cycling between lower-carb and higher-carb days on non-training and training days respectively.
- On training days, carbs would only come in after training during the PM hours (very carb-backloading-esque)
- Refeeding every 7 days with a calorie suplus
Now, there is absolutely nothing wrong with doing any of those things. They don’t cause a health or performance detriment, in and of themselves at least. In fact, they can be extremely effective for the reasons I talked about earlier.
However, there are secondary problems that have the potential to crop up.
The problems can start to creep in when these approaches turn into rigid rules. When you can only be happy functioning when they are adhered to. You become neurotic about them and you don’t know what to do when things get thrown out of whack (i.e. when life gets in the way).
These can be nice little tools and their underlying mechanisms are super interesting to learn about. And over time we may even see research showing they have benefit over a simple linear diet. But the truth is, these are all just little details when we stop and consider the overall picture.
Can intermittent fasting, carb cycling, back loading carbohydrate intake or eating 100% “clean” food be used to achieve health, body composition and performance goals? Of course. Many people have done so.
But minutiae (little details) can often get in the way of the foundational cornerstones. So focusing on things like fasting windows, timing of carbs, needing to “earn” carbs and elimination of food groups when you don’t have the fundamentals taken care of first is a classic case of missing the forest for the trees.
The point is this: Success on any of these strategies only comes when the bigger picture pieces are taken care of. Overall diet quality, caloric intake, macronutrient intake and micronutrient intake/nutrient density. Not to mention sleep, lifestyle, training, etc.
Think about the following hypothetical situation.
A 80kg intermediate-advanced trainee wants to drop body fat. We work out some guidleline calorie and macro figures that would fit this goal. 2,500 kcal/d and 160 g/d of protein. Now, whether we set this up in a linear or non-linear fashion shouldn’t make a massive difference (in my view) as long as the weekly averages are generally on point. Think about 3 possible set-ups:
At the end of the week, we’re hitting the same calorie and macro targets. As long as this dude is able to perform in the gym and recover and stays consistent with his nutrition program, will it really matter which method he picks? My intuition says no.
So what should he pick? Simple. What’s easier to stick to and less stressful? Pick that one.
The lesson is simply this: get the fundamentals in place and practice becoming consistent with them.
- Get a majority of your intake from minimally-processed, “real” food, whilst leaving enough discretionary calories to allow you to eat your favourite foods.
- Hit a calorie intake that matches your goal. Whether this is via tracking calories or from simple portion control is up to you.
- Eat in a way you can see yourself doing for life. Don’t eliminate things you know you are going to exert massive willpower to never eat again.
- Get adequate amounts of the macronutrients. Aim for close to 2 g/kg BW for protein, sometime more depending on the context. Get somewhere between 1.0-1.5 g/kg BW of dietary fat, depending on your preference for more/less carbs.
- Be consistent with lifestyle stuff like exercise, sleep and stress, all of which I’ve talked about ad naseum.
- If you prefer linear dieting, do that. If you prefer to cycle calories or macros, do that.
Do whatever you need to in order to stick to these. Do that and no protocol is going to bring you much of an added benefit. Where those approaches can come in handy is if they make it easier for you to adhere to your diet.
Should I do [insert name of protocol/approach]?
So if you do some form of calorie/macronutrient cycling, you get results from it and you enjoy it, then have at it. It’s awesome for some of the reasons I mention above.
But if you are forcing yourself to do it thinking it will magically give you better results than a more linear approach, then re-evaluate. Pick whatever strategy that allows you to adhere to it without being mentally draining. You want your diet to be as economical as possible (i.e. how can I get the desired result with the minimum amount of mental strain and resource usage?)
Whether you use linear or non-linear dieting your weekly averages should come out the same.
Do you, or have you, followed a non-linear dieting plan? What results did you get from it? Was it easier or more difficult mentally than a linear approach? Have you got caught up in the minutiae? Would love to hear peoples experiences in the comments below, especially as I can discuss how my experience match up.
So, what is your experience of non-linear dieting?