Females using diet breaks did not lose more fat than females following continuous dieting. The two groups had no differences in muscle mass, weight loss, or hunger ratings. Women using diet breaks had higher levels of impulse control (i.e., less likely to binge) than the continuous dieting group.
SUMMARY OF DIET BREAK VS CONTINUOUS DIETING STUDY
Females using diet breaks did not lose more fat than females following continuous dieting.
The two groups had no differences in muscle mass, weight loss, or hunger ratings.
Women using diet breaks had higher levels of impulse control (i.e., less likely to binge) than the continuous dieting group.
WHAT IS A DIET BREAK
Do an internet search for diet breaks. Articles will often discuss the benefits of diet breaks for maintaining muscle and metabolic rate, better satiety control, and greater fat loss compared to continuous dieting. Many people say they use diet breaks to reset their metabolism from continuous dieting.
HOW LONG SHOULD YOU TAKE OFF FROM DIETING?
A diet break is just like it sounds: a temporary increase in calories while dieting. A diet break does not mean you get to eat what you want! You stay on your diet, but instead of being in a calorie deficit or calorie restriction, you raise your calorie levels to maintenance.
Maintenance calories are the number of calories you need to maintain weight. Most people will take a diet break every 2 weeks, but others will use a one-week diet break. Implementing a diet break is designed to provide psychological relief from the stress of dieting while also reportedly increasing metabolic rate and reducing muscle mass loss.
BENEFICIAL IN SOME STUDIES
There has been much debate about the efficacy of diet breaks for preventing metabolic adaptation, as some research has shown beneficial effects while others have shown no effect.
A 2018 study called The MATADOR study found that when subjects reduced their calories for two weeks (~33% reduction in energy intake) and then increased their calories to maintenance levels resulted in weight loss without a loss of lean mass and fat loss compared to a continuous diet group. There was a smaller reduction in resting metabolic rate in the group that cycled their calories. (Byrne et al., 2018)
Campbell et al. reported that 5 days of calorie restriction (35% reduction Monday-Friday) with 2 days of refeeds day back to maintenance (i.e., Saturday and Sunday) resulted in greater retention of lean mass and RMR compared to continuous calorie restriction (~25% caloric deficit, seven days a week). (Campbell et al., 2020)
NOT SO BENEFICIAL IN SOME STUDIES
Contrary to these initial beneficial findings with the initial studies, several studies were published that found no benefit of diet breaks. For example, the ICECAP study was a one-week diet break (i.e., spaced every three weeks) that resulted in a lower hunger than continuous dieting for 12 weeks.
The diet break group also had a 2 fold lower dropout rate than the continuous diet group. (However, the 1-week diet break had similar changes in lean mass, fat mass, and RMR compared to the continuous dieting group. (Peos et al., 2021)
In another study, researchers took resistance-trained females (i.e., 20 years old) with normal body fat (i.e., 25% body fat at baseline) and randomized them to two groups: continuous dieting and a diet break group. The subjects were instructed to reduce their caloric intake by 25% for 6 weeks during the study.
Both groups dieted for six weeks, but the diet break group took a seven-day break (i.e., raised their calories to maintenance levels) every two weeks. The continuous diet break group dieted straight for six weeks.
Both groups lost weight and body fat similarly and maintained lean muscle, with no significant differences between the groups. The diet break group also had lower hunger and desire to eat than the continuous diet group. (Siedler et al., 2020)