Sleep enough if you want to lose fat when you lose weight

An article in this week's Annals of Internal Medicine studied physiologic responses in 10 dieting adults, 5 of whom slept 5 1/2 hours per night and 5 who slept 8 hours a night. The article showed that the 5 who slept less lost 55% less fat than the ones assigned to sleep more despite taking in the same number of calories and losing similar total amounts of weight. Instead they lost more non-fat body mass pounds to make up the difference.

This study included only 10 people, and excluded people who drank a lot of caffeine. Therefore, it is unclear how generalizable the study is.

This study has been extensively misreported as showing that lack of sleep leads to less weight loss while dieting rather than the percent body fat lost. Nonetheless, it suggests that if you are dieting, you may wish to make sure you get enough sleep so that you lose fat instead of non-fat mass. The study should be repeated in a larger sample.

feedback about our health: the ODL

Today I received a newsletter from AHIP, the friendly association of health plans. I learned again about the phrase "observations of daily living", or ODL's. This phrase is bandied about in some projects funded by the Robert Wood Johnson Foundation, studying whether automatically recorded data about our daily lives can help us manage our health. A variety of devices out there are designed to provide real time feedback about our diets, our exercise habits, sleep, sex, smoking, etc.

(I imagine that next - you heard it here - the neurotic and narcissists among us will be replaying our interpersonal interactions in real time for our mental health professionals...my prize is going to go to the person who gets our dreams and waking fantasies to be automatically recorded...)

Fantasies and cynicism aside, these data are extremely helpful to all of us in managing our habits. They can be useful for our physicians in determining what we need help with. However, of course they will also be used to inform our insurers for about our risk status. Be cautious, then, whose tool you use and where the data are going. Make sure the information from these devices goes to a record under your control, not your insurer's. If you are uploading data to your provider organization, is your provider organization authorized to release that data to insurers? These observations bring medical privacy concerns to a new level.

So check out the Zeo a device marketed to consumers that analyzes your sleep. Or Body Media Fit. Several others are listed at Wired.com