Lack of Sleep: A Dieter's Worst Nightmare

Is sleep-loss sabotaging your weight-loss?

Lack of sleep appears to sabotage the effectiveness of dieting, according to new research published in the Annals of Internal Medicine.
The hormonal changes that happen with lack of sleep mess with your diet in a ways that are far worse than you think.



It is not so much you lose less weight when you diet sleep deprived, it appears you lose the wrong kind of weight. Insomnia can lead to losing 4 times more muscle than fat! And muscle is one of the main drivers of your metabolism! So less sleep means less fat loss and slowing metabolism.

Plus, the hormone changes that occur make you more hungry if you lose sleep.

Less fat loss, slower metabolism, and more hunger. Lack of sleep is a dieter's worst nightmare.

Here are the specifics:

The study looked at sleep deprivation and whether it affected the amount and composition of weight lost when dieting, hunger levels, and levels of certain weight and metabolism related hormones.

Researchers randomized 10 overweight adults to 2 weeks of dieting with normal sleep (8.5 hours/night) or 2 weeks of dieting with 5.5 hours per night of sleep.

Reduced sleep decreased the proportion of weight lost as fat by 55%.
-Sleepers lost 1.4 kg of fat, insomniacs lost 0.6 kg of fat.

It also increased the amount of fat free tissue loss (muscle) by 60%!
-Sleepers lost 1.5 kg of muscle, and insomniacs lost 2.4 kg of muscle!

So in this study, dieters who were sleep deprived lost 400% more muscle than fat!

Less sleep led to higher ghrelin levels (the hunger hormone) and increased feelings of hunger.


"Among other hormonal effects, we found that sleep restriction caused an increase in ghrelin levels in the blood. Ghrelin is a hormone that has been shown to reduce energy expenditure, stimulate hunger and food intake, promote retention of fat, and increase glucose production in the body. This could explain why sleep-deprived participants also reported feeling hungrier during the study," senior study author Plamen Penev, MD, PhD, University of Chicago, said in a statement.

It also lowered resting metabolic rate and epinephrine concentration (a fat burning, metabolism revving hormone).

The main limits to the study were the very small sample size and short duration of the study.

"These results highlight the importance of adequate sleep for maintenance of fat-free body mass when dieting to lose weight," according to Dr. Penev.
In an accompanying editorial, Shahrad Taheri, MBBS, PhD, University of Birmingham, United Kingdom, and Emmanuel Mignot, MD, PhD, Stanford Sleep Medicine Center in California, agree that adequate sleep might be an important factor in successful weight loss and suggest sleep might be part of a lifestyle package that has traditionally focused on diet and exercise.

Dr. Taheri and Dr. Mignot conclude that replicating the findings from this study in clinical trials is "a critical next step in addressing important questions about sleep and body weight."

The study was funded by the National Institutes of Health.
Ann Intern Med. 2010;153:435-441, 475-476.

So get out there, push play, then go take a nap!

-