If you want to improve your body composition (lose body fat and/or gain muscle), you should focus on achieving consistent, good-quality sleep.

Sleep is essential for mood, energy levels and performance. Slow-wave or ‘deep’ sleep is restorative and promotes anabolic processes in the body that help to build new muscle tissue and promote recovery after exercise.

Conversely, a lack of sleep or sleep deficiency can have many adverse side-effects, such as hindering exercise recovery and reducing exercise-induced adaptations (eg, the ability to gain muscle or get fitter).

From a fat loss perspective, sleep deficiency is associated with an increase in calorie consumption and a decrease in activity and exercise levels, which will ultimately lead to fat gain over time.

Insufficient sleep has also been shown to lead to unfavourable body composition results with a greater loss of lean mass during intentional calorie restriction. Similarly, sleep restriction can negatively affect appetite control through its impact on hormones that are associated with hunger, satiety and food reward, meaning you’re more likely to eat too much.

In a highly controlled, metabolic ward study on 12-healthy young males, researchers found that fragmented sleep (induced by repeated alarms at 90-minute intervals over one night) reduced rapid-eye movement (REM) sleep more than the normal, non-fragmented sleep. 

Due to effects on hunger hormones, the fragmented sleep group reported less fullness and a greater desire to eat. Not what you want when your goal is to lose body fat! Interestingly, reduced REM sleep is associated with being overweight, further suggesting that REM sleep may influence appetite regulation.

Good sleep quality (with respect to timing, duration & intensity) on a consistent basis, however, can improve memory, cognition and increase total energy expenditure (meaning it’s easier to keep your weight under control.

Here are some simple but effective tips to help ensure good quality sleep:

1. Make sure your bedroom is cool and pitch black.
2. No blue lights (screens) close to bedtime. Blue light can help suppress the production of melatonin, which helps to control your sleep & wake cycles. Use settings on your phone/tablet/laptop to automatically switch off blue light later in the day.
3. Aim to be in bed at the same time every night and wake at a similar time each morning. This is linked to your circadian rhythm and may help maximise your sleep intensity (restorative or ‘deep’ sleep).
4. Aim to get sunlight exposure each morning e.g. a walk outside before noon.
5. Avoid caffeine for about 10 hours before bed. Caffeine has a half-life of about 6 hours, meaning half of the caffeine content in a coffee or energy drink can remain in your system for up to 6 hours after consumption and negatively disrupt sleep quality.
6. Try not to consume an excessively large meal right before bed because sleep decreases the activity of the digestive tract.
7. On the other hand, some people struggle to sleep when feeling hungry. Adjust your meal pattern so you’re neither hungry or ‘stuffed’ at bedtime.

Conclusion
As well as the positive effect of good-quality sleep on mood, memory and wellbeing, good sleeping habits can assist fat-loss and overall body composition.
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It works the other way too – losing body fat and attaining a healthier weight can improve sleep quality and duration. A ‘virtuous circle’ of better sleep and better health!

Kevin Garde
Bodyscan Consultant and Nutritionist