It is a thing but not in the way many people think.

What most people think it is: after dieting your metabolism has slowed down, so by slowly increasing calories you ‘fix’ your metabolism and can eat more calories without gaining fat.

What’s actually happening: people go from eating in a calorie deficit right back to eating how they were before the diet, resultantly they gain fat because they’re back in a calorie surplus NOT because their metabolism is ‘damaged’.

What it actually is: after you end a diet, there is some metabolic adaptation (you require fewer calories to maintain your new body weight). By slowly increasing calories you can find your new maintenance intake without overshooting and gaining fat.

With that said, I think reverse dieting, (especially when undertaken at a stupidly slow rate), is pointless. Once you’ve ended your diet, take your current body weight (in pounds) and multiply it by 12-14 (the former if you’re a woman; the latter if you’re a man). This is roughly your new maintenance. Then simply eat at this number and see how your body responds.

Still losing weight? Increase calories by 5-10%. Gaining more than 0.5-1% per week? Reduce calories by 5%.

Despite what many fitness gurus claim, there is currently no scientific evidence that reverse dieting works, save, of course, from eliminating the head funk many people face from a post diet calorie increase and reducing the risk of overshooting intake.. but what a tedious way to do it!

You cannot alter/increase your metabolism or metabolic rate by introducing more calories slowly and gradually. Our basal metabolic rate increases as we gain weight or muscle mass, and decreases as we lose weight or muscle mass.

Put simply, it is not the speed within which you introduce the additional calories, it’s the number of calories introduced. If you eat more calories than your body requires, you will gain fat. If you eat at maintenance calories or below you won’t.

Finding your maintenance calories post diet, at any speed, will be what prevents post diet fat gain. You cannot increase your metabolism by introducing more calories at a slow rate.