This blog usually focuses on diet, because that's my specialty. But if you want Whole Health, you need the whole package: a diet and lifestyle that is broadly consistent with our evolutionary heritage. I think we all know that on some level, but a recent paper has reminded me of it.
I somehow managed to get on the press list of the Annals of Internal Medicine. That means they send me embargoed papers before they're released to the general public. That journal publishes a lot of high-impact diet studies, so it's a great privilege for me. I get to write about the studies, and publish my analysis at the time of general release, which is the same time the news outlets publish their stories.
One of the papers they sent me recently is a fat loss trial with an interesting twist (1; see below). All participants were told to eat 10% fewer calories that usual for two weeks, however half of them were instructed to sleep for 8 and a half hours per night, and the other half were instructed to sleep for 5 and a half hours
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Showing posts with label Sleep. Show all posts
Showing posts with label Sleep. Show all posts
Wednesday, 1 December 2010
Sleep Post Correction
An astute commenter pointed out that I misread the numbers in the paper on sleep and fat loss. I wrote that out of the total 3.0 kg lost, the high-sleep group lost 2.4 kg as fat, and the low-sleep group lost 1.4 kg of fat out of 2.9 kg total.
In fact, the high-sleep group lost 1.4 out of 2.9 kg as fat, and the low-sleep group lost 0.6 out of 3.0 kg as fat. So I got the numbers all mixed up. Sorry for the mistake. The main point of the post still stands though: sleep deprivation negatively influences body composition.
The correct numbers are even more interesting than the ones I made up. Even in the high-sleep group, nearly half the body weight lost by simple calorie restriction was lean mass. That doesn't make calorie restriction look very good!
In the sleep-deprived group, 80% of the weight lost by calorie restriction came out of lean mass. Ouch!
That illustrates one of the reasons why I'm skeptical of simple calorie restriction as a means of fat loss. When the body "wants" to be fat, it will sacrifice lean mass to preserve fat tissue. For example, the genetically obese Zucker rat cannot be starved thin. If you try to put it on a severe calorie-restricted diet, it will literally die fat because it will cannibalize its own lean mass (muscle, heart, brain, etc.) to spare the fat. That's an extreme example, but it illustrates the point.
The key is not only to balance energy intake with expenditure (which the brain does automatically when it's working correctly), but to allocate energy appropriately to lean and fat mass.Posted byStephanat11:50 PM
View the Original article
In fact, the high-sleep group lost 1.4 out of 2.9 kg as fat, and the low-sleep group lost 0.6 out of 3.0 kg as fat. So I got the numbers all mixed up. Sorry for the mistake. The main point of the post still stands though: sleep deprivation negatively influences body composition.
The correct numbers are even more interesting than the ones I made up. Even in the high-sleep group, nearly half the body weight lost by simple calorie restriction was lean mass. That doesn't make calorie restriction look very good!
In the sleep-deprived group, 80% of the weight lost by calorie restriction came out of lean mass. Ouch!
That illustrates one of the reasons why I'm skeptical of simple calorie restriction as a means of fat loss. When the body "wants" to be fat, it will sacrifice lean mass to preserve fat tissue. For example, the genetically obese Zucker rat cannot be starved thin. If you try to put it on a severe calorie-restricted diet, it will literally die fat because it will cannibalize its own lean mass (muscle, heart, brain, etc.) to spare the fat. That's an extreme example, but it illustrates the point.
The key is not only to balance energy intake with expenditure (which the brain does automatically when it's working correctly), but to allocate energy appropriately to lean and fat mass.Posted byStephanat11:50 PM
View the Original article
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