Diet Breaks and Refeed Days: Do They Actually Work?

Do diet breaks and refeeds "reset" your metabolism?

When you diet, your body pushes back: hormone levels change and you burn less energy, which shrinks your deficit (Trexler and colleagues, 2014).

One of those hormones is leptin, which tracks your body fat and how much you eat. It falls when you diet, and extra carbohydrate pushes it back up: three days of overeating carbohydrate raised leptin by 28% in lean women who were not dieting, while overeating fat did not (Dirlewanger and colleagues, 2000).

Breaks and refeeds are meant to reverse this. There are two problems with that.

• The slowdown is often smaller than people think. In adults with obesity on an 8-week, 1,000-calorie-a-day diet, resting metabolism (the calories you burn at rest) fell about 90 calories a day more than their weight loss explained. That shrank to about 40 once their weight was stable, and to almost nothing a year later (Martins and colleagues, 2020).
• A leptin bump is probably short-lived. After a 3-day fast, leptin fell by about 62% and was back to normal within 12 hours of eating again (Weigle and colleagues, 1997). So any bump from a refeed probably fades soon after the diet resumes, though this has not been tested directly.

Do diet breaks work? What the research in lifters shows

We found two randomised trials of week-long diet breaks in people who lift.

The ICECAP trial (Peos and colleagues, 2021) put 61 resistance-trained men and women on a moderate calorie deficit. Half dieted for 12 weeks straight. The other half dieted in four 3-week blocks with a 1-week break at maintenance between each, 15 weeks in all, eating extra carbohydrate in the breaks.

At the end, there was no clear difference between the groups in fat mass, lean mass (everything that is not fat, including muscle and water) or body weight, nor in resting metabolism, strength or hormones such as leptin and testosterone. But the break group reported less hunger, less desire to eat and more satisfaction.

A trial in resistance-trained women (Siedler and colleagues, 2023) used a 25% calorie deficit, either for 6 weeks straight or in three 2-week blocks with a week at maintenance between each, 8 weeks in all. Among the 38 women who completed it as planned, there were no group differences in body weight, fat mass, lean mass or resting metabolism, and most appetite measures were the same. The exception was "disinhibition", the tendency to overeat when control slips, which rose in the continuous group and fell in the break group.

Put together: in lifters, breaks gave about the same result for the same number of dieting weeks. It just took a few weeks longer, with a possible benefit for appetite.

A 2025 meta-analysis (Poon and colleagues, Nutrition Reviews) pooled 12 randomised trials and 881 people. Weight and fat loss did not differ with or without breaks. Resting metabolism fell less with breaks, though the effect was stronger in people with overweight or obesity than in resistance-trained people.

The MATADOR study: bigger results, but not in lifters

The best-known diet-break study is MATADOR (Byrne and colleagues, 2018). Sedentary men with obesity ate about two-thirds of their maintenance calories. One group dieted for 16 weeks straight. The other alternated 2 weeks of dieting with 2 weeks at maintenance, so the same 16 dieting weeks took 30 weeks.

Men who completed the study	With breaks	Without breaks
Weight lost	14.1 kg (31 lb)	9.1 kg (20 lb)
Fat lost	12.3 kg (27 lb)	8.0 kg (18 lb)
Lean mass lost	1.8 kg (4 lb)	1.2 kg (3 lb)
Total time	30 weeks	16 weeks

There was no clear difference in lean mass lost. Resting metabolism fell by a similar amount in both groups, but less with breaks once the researchers allowed for the fat and lean mass each man lost (roughly 90 vs 180 calories a day). Six months later, among the men followed up, the break group was still further below its starting weight, mostly because it had lost more to begin with.

The results are striking, but they come from sedentary men with obesity on a large deficit with meals provided, and took nearly twice as long. They have not been repeated in lifters, and we found no lifter trial reporting on keeping the weight off. If you lift and are on a moderate cut, expect something closer to the ICECAP result.

Do refeed days work?

The main trial in lifters (Campbell and colleagues, 2020) followed resistance-trained men and women for 7 weeks. One group ate 25% below maintenance every day. The refeed group ate 35% below maintenance for 5 days, then 2 days at maintenance with the extra food from carbohydrate, so the planned weekly deficit was about the same.

Fat loss did not clearly differ: 2.8 kg (6.2 lb) with refeeds and 2.3 kg (5.1 lb) without. The paper reported that refeeds helped keep lean mass and resting metabolism up, but neither difference held up in an independent reanalysis. Only "dry" lean mass (lean mass minus body water) still favoured the refeeds, which the lead author acknowledged in a published reply. So there is a hint that refeeds help keep muscle, but no more. Only 27 people finished, about half of those who started.

What about training? Glycogen (carbohydrate stored in muscle) can refill within about a day of very high carbohydrate eating (Bussau and colleagues, 2002). But in a small study of 11 competitive bodybuilders, a carbohydrate refeed did not change performance in a hard leg-press session (Moura and colleagues, 2021).

The honest verdict: a refeed may make training feel better and the diet easier to stick to, but even that is untested. It is not a proven fat-loss or metabolism booster.

Why the scale goes up after a break or refeed

After a refeed or a break, a rise of a few hundred grams to a kilogram (2 lb) or more is normal. It is mostly glycogen and water, not fat, and should ease back off once you return to the diet. Judge the trend over the following weeks. See how to read the scale.

Muscle stores at least 3 g of water with every gram of glycogen (Fernández-Elías and colleagues, 2015). In ICECAP, weight rose about 0.6 kg (1.3 lb) in a break week with no change in fat. In Siedler's trial it rose about 0.5 kg (1.1 lb) on average, more in some women.

How to do a diet break or refeed day

There is no tested "best" schedule, so these points are common practice and expert suggestion, not research findings.

• Eat at maintenance, not "whatever you want". A break pauses the deficit; it is not a holiday from tracking. Your maintenance is now lower than before the cut, mostly because you weigh less. If you cut on 2,000 calories and maintenance is now about 2,500, eat about 2,500. See how to calculate maintenance calories.
• Keep protein the same and add the extra food mostly as carbohydrate, as the lifter trials did. Here, the extra 500 calories is about 125 g of carbohydrate: rice, potatoes, oats or fruit.
• Keep your training and daily steps the same.
• How long: 1 to 2 weeks for a break, as in the trials. For a refeed, 1 or 2 days: physique athletes often refeed for 24 hours once or twice a week (Trexler and colleagues, 2014).
• How often: the lifter trials put a 1-week break after every 2 to 3 weeks of dieting. A 2019 review (Peos and colleagues) suggested 2 weeks of moderate dieting then 2 weeks at maintenance as a cautious, theoretical option, but that doubles the length of the cut.
• Count refeed days in your week. Unless you eat a little less on the other days, they shrink your weekly deficit.

Who should use them, and who should not bother

Breaks make most sense on a long cut, or when hunger, mood or training are slipping. A 2020 review on nutrition for physique athletes (Roberts and colleagues) calls diet breaks and refeeds "possibly beneficial" for holding on to lean mass during contest prep.

You can probably skip them if:

• Your cut is short and going well. Breaks did not add fat loss in the trials, so they would only add time.
• You are working to a fixed date, such as a show or a holiday. Each week at maintenance pushes your finish back a week.
• A week of more food tends to become a week off tracking. A break only helps if you eat at maintenance, then go back to the diet.

If you have a history of disordered eating, or a health condition such as diabetes, speak to your doctor before planning breaks, refeeds or any diet.

How coaching helps

With one-to-one coaching from CoachAk, you send a weekly check-in that includes your weight, hunger, energy, training and steps. Your coach replies with written feedback and adjusts your calorie and macro targets, so if a break makes sense, they can go up to maintenance for a week and back down after. You can also message your coach directly.

If you want help with a cut you can actually stick to, apply for coaching.