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Refeeds, diet breaks, and carb cycling

Non-linear dieting strategies, such as refeeds, diet breaks, and carb cycling, are fairly popular in the fitness world. An in-depth look at the potential benefits of refeeds and diet breaks can be found in this article about the concept of “metabolic adaptation” to weight loss. Briefly, our bodies have to navigate some changing conditions during relatively substantial or “aggressive” weight loss phases (in this scenario, we’re talking about weight loss attempts that involve a large amount of total weight loss, a rapid rate of weight loss, or attainment of a very low body-fat level). One of the most impactful changes observed is a drop in a hormone called leptin, which can lead to several downstream effects including reduced total daily energy expenditure (TDEE), reductions in thyroid hormones and sex hormones, and increased hunger, among many others. In addition, we tend to partially deplete our glycogen stores during aggressive weight loss phases, which has the potential to negatively impact our strength and fatigue resistance during exercise.

Diet breaks involve taking a short “break” from a calorie deficit by eating at or near maintenance calorie levels, usually for a week or two. In theory, these breaks are intended to attenuate some of the negative physiological impacts of aggressive dieting (which can lead to lower TDEE and increased hunger) and provide some psychological benefits to promote dietary adherence. Some people might also notice some transient performance improvements during training when they switch from a calorie deficit to maintenance calories. There is some preliminary evidence to support some of these intended benefits, but research findings are mixed, so more research is needed before definitive conclusions can be drawn.

Refeeds can take a variety of different forms, but usually involve increasing calorie intake for 1-3 days throughout the week, with a particular focus on increasing carbohydrate intake. In theory, these breaks are intended to transiently increase leptin levels, in hopes of attenuating some of the negative physiological impacts of aggressive dieting that lead to lower TDEE and greater hunger. Refeeds could also acutely refill glycogen stores to provide a transient boost to exercise performance, and some view the brief increase in calories to be helpful from a psychological perspective. Once again, this is an area where more research is needed before definitive conclusions can be drawn about efficacy.

Carb cycling can also take a variety of forms, but invariably involves day-to-day fluctuations in the amount of energy coming from carbohydrate. In most cases, the goal is to strategically shift carbs to high-priority exercise days, in hopes that the extra carbs will top off glycogen stores and increase carbohydrate availability to more effectively fuel performance. When calorie intake is kept constant throughout the week, this usually means eating higher carbs on the days you exercise, and replacing some of those extra carbs with fat and/or protein on your off days. When calorie intake fluctuates throughout the week, carb cycling starts to look a lot like a refeed strategy, in which certain key exercise days have higher total energy intake, mostly or exclusively coming from carbohydrates. While the relationship between carbohydrate intake and high-intensity performance is well established, there is a lack of evidence to directly suggest that carb cycling is inherently advantageous when compared to less variable carbohydrate intake patterns.

Why Doesn’t MacroFactor Have a Diet Break Mode?

We follow the scientific evidence related to diet breaks very closely. In fact, we participate in it – our very own Dr. Trexler has actually collaborated on scientific research investigating diet breaks. There are two reasons that MacroFactor doesn’t have a dedicated “diet break mode.” First, there is currently insufficient evidence to conclusively identify the exact physiological and psychological benefits that are (or aren’t) attained from diet breaks, and insufficient evidence to conclusively describe an “optimal” approach to scheduling diet breaks. Second, diet breaks can already be done with tremendous ease in MacroFactor, without the need for a dedicated mode of operation. While we don’t want to overstate the potential benefits of diet breaks or promote unrealistic expectations by creating a separate mode within the app, we designed the app to enable diet breaks for those who wish to utilize them.

How To Do a Diet Break in MacroFactor

There are two easy ways to implement a diet break in MacroFactor.

First, you could simply do it, and opt not to change any settings at all. MacroFactor is adherence-neutral, and responds to what you actually did, rather than what your targets were supposed to be. It also presents a TDEE estimate on your dashboard that is continuously updating to give you an accurate value. So, you could simply increase your calorie intake to approximately match your current TDEE estimate for a week or two, while ensuring that you’re getting fairly close to your protein target as well. After this 1-2 week period, you could start aiming for your listed targets again, and the diet break has been implemented successfully without the need to change any settings.

Alternatively, you could edit your goal to “maintenance” for 1-2 weeks, then switch back to your original goal when you’re done with the diet break. Some users might be bothered by the concept of switching their goal, as they might feel like they’re abandoning the goal prior to accomplishing it, or throwing away their progress toward the goal and starting over. Of course, neither is the case; MacroFactor maintains continuity when you switch goals, so there shouldn’t be any concern or hesitation about temporarily shifting to maintenance for a couple weeks, then shifting right back to your original goal.

Why Doesn’t MacroFactor Have a Refeed Mode?

Again, we follow the scientific evidence on this topic very closely, and Dr. Trexler has written fairly extensively about refeeds in his own research and articles dating back to 2014. Needless to say, the decision to omit a dedicated “refeed mode” from MacroFactor was an intentional decision rather than an oversight. Much like diet breaks, there is currently insufficient evidence to conclusively identify the exact physiological and psychological benefits that are (or aren’t) achieved from refeeds, and insufficient evidence to conclusively describe an “optimal” approach to scheduling refeeds. In fact, there’s quite a bit of variability when it comes to the implementation of refeeds.

One popular strategy, especially during weight loss phases, is to have 2-3 refeeds on consecutive days. On these days, energy intake is often increased to (or above) maintenance levels, with the additional calories coming from carbohydrates. Another popular strategy is to strategically place refeeds the day before (or the day of) particularly important or arduous training sessions (usually implementing 1-3 non-consecutive refeeds per week). If you train in the morning, refeeding the day before a big training session would be an intuitive approach, while refeeding the day of the training session would make more sense if you train in the late afternoon or evening.

Similarly to our view on diet breaks, the MacroFactor team doesn’t want to overstate the potential benefits of refeeds or promote unrealistic expectations by creating a separate mode within the app. Nonetheless, we designed the app to enable refeeds for those who wish to utilize them, and they can be easily implemented without the need for a separate mode of operation.

How To Do a Refeed in MacroFactor

There are two easy ways to implement refeeds in MacroFactor.

Just as described for diet breaks, you could simply implement refeeds as you wish, without the need to change any settings at all. MacroFactor is adherence-neutral, and responds to what you actually did, rather than what your targets were supposed to be. You could simply choose 1-3 days throughout the week to increase your calorie and carbohydrate intake, and MacroFactor will roll with the punches and continue to adjust without any unfavorable impacts on app function.

Alternatively, you could choose to operate the app in collaborative mode (or manual mode) rather than coached mode. Collaborative mode is designed to give you the freedom to adjust calorie, carb, fat, and protein targets on a day-to-day basis within your macro plan, all while keeping you on track with your weekly calorie target. This functionality is perfectly suited to enable just about any refeed strategy you’d be interested in applying. Manual mode offers maximal flexibility for setting day-to-day nutrition targets, so it’s also perfectly suited for a wide range of refeeding strategies.

Why Doesn’t MacroFactor Have a Carb Cycling Mode?

We’re well aware of the fact that many exercisers like to consume more total energy on their training days than their off days, which is exactly why we have the “calorie shifting” feature in the coached mode of MacroFactor. This accomplishes what most people are aiming to accomplish with some of the more common carb cycling strategies.

When it comes to cycling carbs while keeping daily energy intake consistent, we simply haven’t seen sufficient evidence to conclude that carb cycling is inherently advantageous when compared to more linear approaches to carbohydrate intake. So, in the interest of simplicity and a streamlined user experience, we do not offer that particular form of carb cycling as a specific mode of operation. However, it can still be achieved quite easily in MacroFactor.

How To Do Carb Cycling in MacroFactor

There are two easy ways to implement carb cycling in MacroFactor.

The first option is to simply do it, without changing any app settings. Given the adherence-neutral nature of MacroFactor, the exact macro targets presented on any given day are just guidelines. If you decide to replace some fat calories with carbohydrate calories, or vice versa, this will not have any unfavorable impact on the function of the app. The same is true if you decide to simply eat extra carbs rather than substituting carbs for fat. In fact, due to our goals and preferences, the MacroFactor team generally doesn’t sweat our exact ratios of carbohydrate to fat. We always aim to get reasonably close to our protein goal (or higher) and achieve our minimum advisable fat intake, but trading carbs for fats (or fats for carbs) is a very common occurrence – not to gain an advantage from carb cycling, but merely to accommodate our dietary preferences.

Alternatively, you could choose to operate the app in collaborative mode (or manual mode) rather than coached mode. Since collaborative mode gives you the freedom to adjust calorie, carb, fat, and protein targets on a day-to-day basis within your macro plan, you can easily implement a wide range of carb cycling strategies while staying on track with your weekly calorie target. Of course, the same is true for manual mode, which offers even greater flexibility.

Summary

The goal of coached mode is to provide the most helpful and efficient guidance possible, without introducing unnecessary complicating factors that may alter macro targets or food choices from day-to-day. Any strategy that introduces additional complication and variability should be implemented cautiously, as any potential advantages must be balanced against the cost of sacrificing simplicity and consistency throughout the week. In addition, the decision to create a separate mode of operation for a given dietary strategy could potentially contribute to unwarranted hype or promote unrealistic expectations if the strategy doesn’t have a robust body of scientific evidence to support its implementation.

When it comes to diet breaks, refeeds, and carb cycling, we simply haven’t seen enough scientific evidence to justify the creation of separate modes of operation. However, it is quite possible that these strategies could be effective in some very specific situations, and it’s also very likely that these strategies will match up well with the preferences of some of our users. As such, we made sure that MacroFactor would allow for all of these strategies to be implemented quite easily. A diet break can be implemented by nothing more than a quick, temporary switch to a maintenance goal. Due to the relative lack of scientific research on refeeds and carb cycling, there is not a single “correct” way to structure these nonlinear dietary strategies. So, the most efficient and straightforward way to enable these strategies while allowing for a sufficient degree of customization was to accommodate them within collaborative mode or manual mode.

In conclusion, MacroFactor doesn’t have specific goals, settings, or modes of operation for diet breaks, refeeds, or carb cycling, but it was designed to enable all three for users who may choose to implement them.