I read an intriguing article in the 5 October, 2010 edition of Annals of Internal Medicine, then saw the accompanying editorial. The article was titled "Insufficient Sleep Undermines Dietary Efforts to Reduce Adiposity" and was densely scientific, even for me; the editorial was titled "Sleep Well and Stay Slim: Dream or Reality." I decided to start with the commentary and then return to the study itself.

Having read both in detail, I'm comfortable with what's said and what the limitations of the study, done at the University of Chicago and the University of Wisconsin, might be. So let's start there.

The researchers put newspaper ads in local papers to recruit a small number of subjects for a short-term study. They ended up with ten volunteers who didn't smoke, were overweight, but otherwise healthy. The study protocol was detailed ,but basically each of the subjects was on a two-week diet with eight hours or sleep and another similar period with five and a half hours of sleep.

They lost similar amounts of weight in both study periods, but lost more fat during the time they when they dieted and slept well. So sleeping less and dieting resulted in the loss of "fat-free body mass." In other words they lost more fat and less muscle when they slept longer and vice versa when they slept less.

How does this apply to the rest of us? Well there is some data linking a decreased sleep duration with an increase in obesity rates in larger groups. There are rodent studies supporting the theory. There are some larger human studies showing shorter periods of sleep are associated with changes in two hormones that affect appetite and one that showed an association between snacking and less sleep.

So there's a lot of data accumulating that strongly suggests, but does not yet, from a strictly scientific point of view prove, that if we need to lose fat we should diet and also get adequate amounts of sleep.

It makes sense to me. I wouldn't hold my breath waiting for large studies in general populations that confirm this small-scale research. We are a chronically under-slept nation, a number of sources have proclaimed, and I think they're right.

So cutting your hours of sleep while you diet appears to be self-defeating and sleeping a full eight hours, give or take a little, is probably better if you want to lose fat.

This entry was posted on Wednesday, October 20th, 2010 at 10:20 am and is filed under Dieting, medically-oriented background info, Obesity, Weight Loss. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.