This knowledge base article provides a (relatively) brief answer to this question. For an in-depth answer, we'd recommend checking out this article.
Our bodies have to navigate some changing conditions during relatively substantial or “aggressive” weight loss phases (that is, 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). The term “metabolic adaptation” can be used to describe this collection of changes, which are summarized in this article on the topic. In short, the combination of energy restriction and fat loss can lead to reduced levels of a hormone called leptin, which has a wide range of downstream effects such as reduced total daily energy expenditure (TDEE), reduced levels of thyroid hormones and sex hormones, and increased hunger, among many others. As a result, individuals focusing on weight loss may find themselves in the difficult position of having a calorie target that is atypically low for them, while simultaneously experiencing hunger levels that are atypically high for them.
In recent years, reverse dieting has emerged as a potential strategy to reverse the effects of chronic energy restriction. The general premise with reverse dieting is that calories are incrementally added back to the diet. This process is typically started after a weight loss goal has been achieved, or when an individual begins to view their low calorie target and high hunger level as an unsustainable pairing. As calorie intake is gradually increased, some aspects of metabolic adaptation may be reversed over time. In some cases, TDEE may increase to a degree that nearly matches the increase in caloric intake, which would allow the dieter to work up to a more sustainable calorie target without substantial gain of fat mass. Theoretically, this would allow the dieter to transition into a maintenance phase with a comparatively higher caloric intake, which could facilitate a more successful and more enjoyable maintenance phase.
There are certainly instances in which people slowly raise calories and manage to reach fairly high caloric intakes while staying lean, but there are pretty straightforward explanations for why this occurs. In the initial stages of slow overfeeding, they are simply correcting a temporary suppression of their TDEE that was transiently induced from energy restriction. Their metabolic rate was lower than it normally would be when they were dieting, and so they begin to restore it to its normal level when calorie intake starts climbing.
After the suppression of TDEE is rectified, there is also the potential for the opposite effect to occur; in response to overfeeding, some people dramatically increase their TDEE to prevent weight gain. There is a great deal of variability between people for this response; as you might imagine, individuals prone to weight gain typically have a very minor increase in TDEE when they are overfed, while individuals resistant to weight gain display large increases.
Based on this logic, some people have promoted reverse dieting with a degree of excitement and confidence that is a bit disproportionate to the supporting scientific evidence. This has given rise to misconceptions about reverse dieting, and led many to believe that you can reliably expect to dramatically increase your calorie intake and TDEE without gaining weight, as long as you do it slowly enough. If you are planning to perpetually increase calories slowly in order to create a super-charged metabolic rate, don’t bother – the premise of fabricating a new metabolic rate from scratch is implausible. We only have the capacity to restore a transiently suppressed level of TDEE, and we have two primary tools to use: more calories, and more time spent in a caloric surplus.
Why Doesn’t MacroFactor Have a Reverse Diet Mode?
The MacroFactor team follows this research very closely, and it’s been on their radar for quite some time. In fact, Dr. Trexler was mentioning reverse dieting in his research dating all the way back to 2014. It’s an interesting concept, and as described in this article, there are some mechanistic reasons to believe that reverse dieting (and a very related concept known as “recovery dieting”) can be useful in some very specific scenarios and situations.
However, there is not sufficient scientific evidence to promote reverse dieting as an unequivocally efficacious strategy, or to guide exact protocols and strategies for structuring a reverse diet. In addition, reverse dieting is a pretty specialized strategy that probably has fairly limited utility for the typical dieter. It might have some potential in the context of fairly aggressive weight loss practices or large magnitudes of weight loss, but the typical dieter following advisable weight loss guidelines probably doesn’t have an enormous degree of metabolic rate suppression to rectify in the first place (beyond the rectification that would occur from simply getting out of a caloric deficit).
So, in the majority of cases, the hype surrounding reverse dieting promotes some pretty unrealistic expectations and is likely to lead to some disappointment. For this reason, we don’t have a dedicated “mode” or “setting” for reverse dieting in MacroFactor. However, we don’t discount the possibility that some users may benefit from reverse dieting, or may just want to give it a shot, so we made sure it was possible to accomplish within the app.
How To Do a Reverse Diet in MacroFactor
In reality, reverse dieting is a very, very simple process. All you do is slowly add calories and observe. To do a reverse diet in MacroFactor, simply change your goal to weight gain, set a fairly large weight gain goal (>10-15 lbs or so) to ensure that a transient blip in water weight won’t inadvertently bump you over the set goal weight, and select the lowest possible rate of weight gain.
If TDEE is staying relatively stable and you’re gaining weight at the exact rate you selected, without the need for continuous calorie increases, then it’s unlikely that any adaptive increases in TDEE are occurring. In other words, you’re not in a physiological state that would enable you to meaningfully benefit from a reverse dieting strategy. Of course, there’s no harm done in this scenario; with such a slow rate of weight gain selected, you’ve effectively taken a diet break by spending a short period of time in approximate weight maintenance, rather than regaining a substantial amount of weight. Someone in this position isn’t likely to obtain the theoretical physiological benefits of a controlled reverse diet, so they should consider whether they want to gain, lose, or maintain their current weight, and update their goal accordingly.
Conversely, if MacroFactor is slowly but consistently increasing your calorie target week over week, you’re probably nudging your TDEE upward and achieving what reverse dieting is intended to achieve. The algorithm will be attempting to promote extremely slow weight gain (slow enough to consider practically negligible), so if your body keeps adapting by increasing TDEE, MacroFactor will continue to slowly add calories to your weekly targets. Of course, this adaptive potential is inherently limited; some people will be able to push their TDEE higher than others, but everyone will eventually reach a point where this adaptive capacity is maxed out. When you reach this point, you’ll observe that TDEE is staying relatively stable and you’re gaining weight at the exact rate you selected, without the need for continuous increases in calorie targets. Once this point is reached, you should consider whether you want to gain, lose, or maintain your current weight, and update your goal accordingly.
Alternatively, users who want a more customized reverse diet can simply operate MacroFactor in manual mode. This mode of operation offers maximal flexibility for setting day-to-day nutrition targets, so users can decide exactly when and how they want to add more calories throughout the course of their reverse diet.
Summary
Reverse dieting sounds like a very nuanced and advanced strategy, but it’s actually very simple – all you do is slowly add calories and observe. The only dieters who stand to reap meaningful physiological benefits from reverse dieting are those whose TDEE is suppressed to a noteworthy degree. Due to the context-specific applications of reverse dieting and the lack of scientific research on the topic, MacroFactor does not have a dedicated goal, mode, or setting for reverse dieting. Nonetheless, we made sure that MacroFactor would allow for reverse dieting strategies to be implemented quite easily for users who may choose to implement them.