Diet breaks – the booster for fat loss?
Are diet breaks beneficial for fat loss? - How efficient is this form of food intake?
Nowadays there are more and more overweight people. Many then turn to diets for fat loss. Diet breaks are apparently beneficial for fat loss.
What matters when we want to lose fat?
The main component of weight loss is the energy balance (energy intake - energy expenditure). If the energy balance is negative, body weight is reduced and body fat is possibly lost. However, when body weight drops, energy expenditure usually drops as well. The reduction in energy expenditure is partly explained by a reduction in body weight.
However, the reduction in energy expenditure cannot be fully explained by weight loss alone. There are additional metabolic adaptations that apparently contribute. This adaptation is called adaptive thermogenesis.
Diet breaks - What does a current study say about this adaptive thermogenesis?
The current study assumed that adaptive thermogenesis could be minimised by inserting "breaks" during the diet period.
The study design
One group (group 1) dieted for 16 weeks. Participants consumed 33% fewer calories. The other group (group 2) also dieted for 16 weeks, consuming 33% fewer calories. However, after every two weeks of dieting, group 2 took a two-week break, during which they consumed the calorie amount for a balanced energy balance (diet break). The total duration of the diet for group 2 was therefore 30 weeks, but the total caloric deficit over these weeks was the same as for group 1.
Group 2 (group with diet breaks) lost more fat mass compared to group 1 (without diet breaks/12.3 versus 8.0 kg), while the loss of lean mass (mainly muscle mass) was similar between the groups (1.8 vs 1.2 kg). The weight change during the diet breaks was almost zero (0.0 ± 0.3 kg body weight). The differences in fat loss therefore occurred during the diet periods.
The reduction in resting energy expenditure (basal metabolic rate) was thus lower in the group with diet breaks, which suggests that the diet effectively dampens adaptive thermogenesis.
Conclusion on diet breaks
Apparently diet breaks can increase fat loss by partly counteracting the decrease in resting energy expenditure (basal metabolic rate) during the diet period.
While the group with diet breaks lost more fat, the diet lasted almost twice as long.
One could of course argue that a diet without breaks for 30 weeks at an energy intake 33% below energy expenditure would lead to the same or more fat loss. Of course, the total calorie deficit would then be much larger and the diet would be significantly more demanding from a mental perspective.
Source: https://www.ncbi.nlm.nih.gov/pubmed/28925405
