How Lack of Sleep Wrecks Your Diet

Regular readers will recall the many previous posts on the relationship between lack of sleep and weight gain. Now new evidence shows that lack of adequate sleep may be even more detrimental in anyone trying to lose weight.

In a study published in a recent issue of the Annals of Internal Medicine, Arlet Nedeltcheva and colleagues from the University of Chicago, tested the hypothesis that lack of sufficient sleep adversely affects the neuroendocrine response and metabolic effects of caloric restriction.

In a complicated randomised, 2-period, 2-condition crossover study, 10 overweight nonsmoking adults (3 women and 7 men) with a mean age of 41 years and a BMI around 27, were subjected to 14 days of moderate caloric restriction with 8.5 or 5.5 hours of nighttime sleep in a sleep laboratory.

Despite the same amount of caloric restriction, sleep deprivations resulted in 55% less fat loss and alarmingly increased the loss of fat-free mass (muscle) by almost 60%.

Sleep deprivation was also associated with increased hunger and reduced fat oxidation.

The authors conclude that adequate sleep is important to prevent the loss of fat-free mass during weight loss.

As a corollary to this, we can perhaps also conclude that trying to lose weight during times of sleep deprivation may be counterproductive in that it is more likely to lead to loss of lean tissue than get rid of the unwanted fat.

I have often advised my time-pressed patients that if they had to chose between 60 mins of exercise and 60 mins of sleep to go for the sleep. This is particularly true, as we know that exercise further increases the need for sleep thereby, making the degree of sleep deprivation, which many of my patients already face, even worse.

I propose that a careful sleep history (if not a formal sleep study) and sleep counseling should be part of every bariatric assessment and weight management plan.

Montreal, QC

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Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, & Penev PD (2010). Insufficient sleep undermines dietary efforts to reduce adiposity. Annals of internal medicine, 153 (7), 435-41 PMID: 20921542