Typically if someone is seeking to optimize their body composition they focus in on either their training routine or diet and try to adjust accordingly.  While this is a natural reaction and alterations to either of these items can get them on the right track, one item they can assess that might help them get their desired results is focusing in on how much sleep they’re getting.

A randomized control trial was carried out on adults who were considered habitually short sleepers (they slept between 5 to <7 hours a night).  These adults were split into a sleep extension group that received consultations to improve sleep hygiene and a control group who did not get any consultation.  An item that the researchers noted was that the sleep extension group in addition to increased sleep duration also improved their nutrition during the day.  The sleep extension group reduced their intakes of fats, carbohydrates, and free sugars (by free sugars the authors were referring to sugars added to foods by manufacturers like corn syrup or added to a meal at home like table sugar).  In the case of free sugars, the reduction amounted to about 10 g less a day in the extended sleep group compared to the short sleepers group.

In case you were wondering what were some items that the sleep extension group was advised during their consultation, it included simple things like avoiding caffeine before bedtime, developing a relaxing bedtime routine, not going to bed too full or too hungry, and having a consistent bedtime.[1]

This study was consistent with previous research showing that poor sleep can sabotage body comp goals.  A study done on overweight adults following moderate caloric restriction with either 8.5 or 5.5 hours of sleep showed that reduced sleep decreased the fraction of weight lost as fat by 55% and increased the loss of fat-free body mass by 60%.  In other words, they lost muscle mass and kept on fat, the least desirable scenario for someone that’s cutting calories.[2]  A separate study this time on normal weight healthy men examined the effects of sleep loss on the endocrine system.  The researchers discovered that a single night of sleep deprivation increased feelings of hunger and plasma ghrelin levels by 22%[3]  Ghrelin is a hormone that regulates hunger as well as energy distribution in the body.

If you’re looking to be proactive about improving their sleep quality you’d be wise to follow some of the recommendations given to the people in the sleep extension study: developing a consistent sleeping routine, finding a way to unwind before bed, practicing sound evening nutrition, avoiding caffeine, and light exposure.

References

[1] https://academic.oup.com/ajcn/article/107/1/43/4794751

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951287/

[3] https://www.ncbi.nlm.nih.gov/pubmed/18564298