Do Diet Breaks Allow You to Preserve More Muscle Mass During a Fat Loss Phase?

A diet break is exactly what it sounds like. A period in which a dieter returns to maintenance level calories during a fat loss phase.

Your average diet has a person restricting calories for a set amount of time, say 12 weeks for example purposes.

During this 12-week period the individual is going to simply remain in a caloric deficit for the duration of the 12 weeks. Attempting to lose as much as possible during that time.

A diet break is going to alter this by having the individual in a caloric deficit for say 6 weeks, then take 1-2 weeks increasing calories to maintenance levels.

The idea behind this is to spend less prolonged times in a catabolic state, (a state of breaking down). Which is what the fat loss phase is. Anytime we are in a caloric deficit we are breaking down, not growing.

But do diet breaks actually provide any benefit?

To answer this question, we must look at the negatives of being in a caloric deficit.

Dieting, especially crash dieting, that extend for long periods of time can have a variety of adverse side effects, these include.

•  Suppressed metabolism
• Loss of muscle mass
• Weight loss plateaus (which can cause future weight loss to become more difficult)
• Increased hunger (which can cause increased irritability)
• Decreased energy levels

This is where a diet break is going to come in. In theory an effective diet break is going to allow you to mitigate the down regulation of the metabolism during an extended fat loss phase, which would in turn eliminate the weight loss plateaus that inevitably happen as we diet for extended periods of time. Further the diet break would preserve muscle mass because it pulls us out of the catabolic process of fat loss and brings us back to an anabolic state allowing for the maintaining of muscle mass.

You may be familiar with the ‘Matador Study’ in which they tested this and found that for those that took diet breaks they saw far more muscle retention than the group who did not utilize diet breaks.

But you need to consider that they performed this study on sedentary obese men. This provides no information on what a diet break would do for someone who is already a trained individual.

Luckily there is a study that was done on resistance trained females in the early 20s who all had around 3 years of training under their belts.

All the subjects had a body fat level of approximately 25% at baseline.

They divided the subjects into two groups.

• The Continuous Dieting Group
• The Diet Break Group

Both groups spent a total of 6 weeks in a deficit. The DBG took a diet break after every 2 weeks, making them have a total of 8 weeks of dieting (6 weeks of deficit, 2 weeks at maintenance).

Both groups deficit and workouts were equated.

So, what were the results?

Both groups regardless of diet break or not, lost statistically significant amounts of weight. In terms of lean mass, both groups were able to retain their lean mass (for the most part) during the 6 weeks of deficit.

There was a small decrease in lean mass in the DBG and a slight increase in the CDG, but these numbers were not statistically significant.

Both groups maintained their metabolic rates in fact they both saw about a 12 calorie increase in their Resting Metabolic Rate. Which is significant because it tells us that they would have been able to continue losing weight if they had continued with the diet as their metabolisms did not down regulate.

So, the big take away from the study is that diet breaks provide no major benefit to maintaining or preserving lean mass during the fat loss phase in resistance trained individuals compared to just continually dieting.

However, this does not mean that a diet break does not have its place and purpose.

A diet break can play a much bigger role than simply maintaining lean mass. A diet break really comes into use when we start to talk about the mental side of the diet.

Another study done by the University of Western Australia in which resistance trained male and female participants dieted for 12 weeks. The CDG were in a deficit for 12 straight weeks, where the DBG took a weeklong diet break every 3 weeks of deficit.

By the end of the study the hunger scores in the CDG were significantly higher than the DBG. Also, the “desire to eat” was significantly higher in the CDG.

This data was similar in both studies. This means that when resistance trained individuals take diet breaks during the fat loss phase, they are likely to be less hungry, less desire to eat, and less chances of overeating in the presence of highly palatable foods or stressful situations. Allowing for better sustaining of the fat loss that was achieved.

So, what is my opinion on whether you should utilize diet breaks during your fat loss phase?

Once again, this is going to depend on the individual. A history of negative food relationships, just really dislikes being hungry, has a very highly adaptive metabolism, etc. may be some reasons I may choose to have a client utilize diet breaks. As we have learned diet breaks really have no overall effect on retaining lean mass but do have a large effect on overall hunger levels throughout and after the fat loss phase. Which can make remaining in a calorie deficit easier during the deficit periods.

You also must consider that any diet breaks you add in are going to extend the overall fat loss period. So, depending on how fast or slow you are looking to get through your fat loss phase is also going to play a part in whether you should choose to utilize diet breaks.

Ultimately though, it is up to the individual. As most things in the fitness and nutrition world are.