Insufficient sleep hampers fat loss?

Can insufficient sleep hamper your diet?

Sleep restriction has been shown to have several detrimental health effects. Does sleep restriction also impact fat loss?

This study investigated the effect of sleep duration on fat and lean mass loss in overweight subjects during two weeks of dieting.

Participants spent 5.5 h or 8.5 h in bed and stayed at the laboratory during the whole study period while all food was provided (90% of resting metabolic rate to induce weight loss).

Key findings:

• The 5.5 h condition lost 55% less fat mass compared to the 8.5 h condition (0.6 vs 1.4 kg).
• The 5.5 h condition lost 60% more lean body mass compared to the 8.5 h condition (2.4 vs 1.5 kg).
• The 5.5 h condition also had higher levels of activated ghrelin (a hunger hormone).

Interpretation?

Total weight loss was similar between conditions (as caloric intake was controlled), but what type of tissue was lost differed substantially. Sleep restriction had a catabolic effect, shifting the composition of weight loss towards lean mass and away from fat mass.

A strength of this study was that the time in bed and nutritional intake was tightly controlled because the participants stayed and were supervised at the laboratory for the entire study duration.

However, sleep restriction may also have a detrimental effect on food choices. Therefore, a limitation of this approach is that the effect of sleep restriction on fat loss may be even worse when nutrition intake is not controlled.

How much time in bed do you get and how many of those are you actually sleeping?

Study:
Nedeltcheva et al, Insufficient sleep undermines dietary efforts to reduce adiposity. Annul Intern Med, 2010

Go to the next infographic in the sleep series:
Caffeine decreases sleep duration?