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Do Your Clients Need a Diet Break?

What Is a Diet Break?

A diet break is when a person on a diet increases their calorie intake to maintenance, typically for a week or two. The objective is to provide psychological relief on a long-term weight loss plan and help reverse some of the physiological changes due to dieting. For example, a person could spend eight weeks in a calorie deficit and temporarily bump calories to maintenance for a week or two before resuming the diet.

Are Diet Breaks Valid?

Diet breaks first gained popularity after Byrne et al.’s 2017 MATADOR study was published. As the acronym suggests (MATADOR: minimizing adaptive thermogenesis and deactivating obesity rebound), the paper studied the effectiveness of weight loss protocols.

In the study, 51 obese men were split into two groups:

  • 16 weeks of continuous caloric restriction
  • Eight 2-week dieting blocks alternating with seven 2-week blocks at maintenance

The second group spent the same amount of time in caloric restriction, but it took them 30 weeks because of the frequent diet breaks.

Interestingly, despite spending similar amounts of time in a deficit (which was controlled, and calorie needs were re-calculated over time), the group taking diet breaks lost more weight and fat while experiencing smaller metabolic adaptations.

While this is perhaps a more extreme application of diet breaks (after all, most people wouldn’t want to spend twice as much time to reach their fat loss goals), it validates the concept. 

Experts like Layne Norton (Ph.D. in Nutritional Sciences) recommend diet breaks to minimize the harmful effects of prolonged dieting and increase people’s fat loss success.

What This Means For Coaches

Alternating between 14-day blocks of dieting and maintenance calories (like in the MATADOR study) is impractical and likely not necessary for most people.

A better approach when coaching people through fat loss phases is to implement a diet break for every four to ten weeks spent in a calorie deficit. This is a big range, so allow me to elaborate. 

How often someone needs a diet break will largely depend on:

  1. How long they’ve been dieting so far
  2. What their body fat percentage is

For example, a person with obesity might only need a diet break every 16-20 weeks because of the high body fat percentage and the overall impact of caloric restriction on metabolic rate and hunger. Someone overweight but not obese (say, 22-25% body fat) may need a diet break a bit more often: every 10-12 weeks.

In contrast, a bodybuilder at around ten percent body fat will typically need a diet break every 4-6 weeks during contest prep. This is because the leaner the individual, the more significant the impact of caloric restriction on their hunger levels, performance, recovery, mood, sexual health, and overall well-being. 

As for food intake, a diet ‘break’ doesn’t mean eating freely. Caloric control is still important to stay around maintenance and not gain body fat. For example, if a client is eating 2,300 calories and losing a steady 0.5-0.7% of their body weight weekly, it would be reasonable to bump their intake to 2,800 calories.


1. How long should a diet break last?

A diet break typically lasts for a week or two, depending on the person’s needs. The optimal length is determined by a person’s body fat percentage and how long they’ve been in a calorie deficit.

2. Can diet breaks help with muscle retention?

Diet breaks can reverse some of the adverse physiological changes that result from being in a calorie deficit and may have a small positive impact on muscle retention, particularly in competitive bodybuilders who get extremely lean to step on stage.

3. Can a diet break impact metabolic rate?

Diet breaks slow metabolic adaptation to dieting (the body’s tendency to lower its energy expenditure during caloric restriction), allowing people to continue losing weight while consuming more calories.

4. How to calculate calorie intake for a diet break?

Assuming the client is in a reasonable deficit and losing 0.5-0.7% of their body weight weekly, that would mean increasing their calorie intake by 400-500 for the duration of the break and monitoring body weight.

5. How are diet breaks different from refeed days?

Diet breaks and refeed days involve a controlled increase in calories to maintenance, primarily by consuming more carbs. The primary difference is that a diet break typically lasts for a week or two, whereas refeeds last for one to three days.

6. How are diet breaks different from reverse dieting?

A diet break is a temporary increase in calorie intake before resuming weight loss. In contrast, a reverse diet is when the caloric restriction period is over, and the person gradually increases their food intake to improve hormonal health and limit fat gain.

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