Sleep Loss May Rev Up Appetite
Mon Dec 6, 2004 10:20 PM GMT
By Amy Norton

NEW YORK (Reuters Health) - Consistently getting a good night's sleep may be one of the answers to maintaining a healthy weight, if early research findings are correct.

The small study found that when healthy young men slept for only fours hours on two nights in a row, they showed dips in a hormone that suppresses appetite, coupled with increases in an appetite-stimulating hormone.

On top of that, the volunteers reported being more hungry after their sleep-deprived nights than after nights when they slept for 10 hours.

Though more research is needed, the new findings suggest that "if you do not run a sleep debt, you will be able to curb your appetite more easily and maintain or lose weight," study leader Dr. Eve Van Cauter, a professor of medicine at the University of Chicago, told Reuters Health.

Van Cauter and her colleagues report the findings in the Annals of Internal Medicine.

The two appetite-regulating hormones in question are leptin, which is released from fat cells and helps alert the brain that it's time to stop eating, and ghrelin, which is produced in the stomach and helps trigger hunger.

Van Cauter's team found that when the 12 men in their study slept for four hours on two consecutive nights, their levels of leptin were 18 percent lower and their levels of ghrelin were 28 percent higher than they were after two nights of spending 10 hours in bed.

When the men were asked to assess their appetites after sleep restriction, they showed a 24 percent increase in their "hunger ratings." And the foods they craved most were sweets, salty foods like chips and nuts, and starchy fare like bread and pasta.

The exact reasons for the hormonal changes associated with sleep deprivation are not yet known. According to Van Cauter, the mechanism may have to do with a small area in the brain where neurons respond to both eating and sleeping.

"We hypothesize that these neurons would be activated by sleep deprivation and stimulate ghrelin and decrease leptin," she explained.

Van Cauter and her colleagues point out that the rise in obesity in the U.S. has occurred in concert with a decline in time spent sleeping. Currently, less than one-quarter of young American adults sleep eight to nine hours per night -- down from about 41 percent in 1960.

Whether these trends are related is unclear. There are ongoing studies, Van Cauter said, that are comparing weight changes over time among "short" and "long" sleepers.

In addition, studies in her team's lab are testing the hypothesis that sleep deprivation may thwart people's efforts to lose weight through dieting.

An editorial published with the report calls the findings "provocative," but adds that key questions remain. One of these is how well the results of a research experiment translate into the real world, according to Drs. Jeffrey S. Flier and Joel K. Elmquist of Beth Israel Deaconess Medical Center in Boston.

Still, they write, if further studies confirm the findings, the "simple goals" of getting both more exercise and a better night's sleep "may well become a part of our future approach to combating obesity." SOURCE: Annals of Internal Medicine, December 7, 2004.

I might believe that lack of sleep might stimulate appetite. I really don't know. However I don't believe their assertion that "Consistently getting a good night's sleep may be one of the answers to maintaining a healthy weight". I value my sleep greatly for the simple fact that I don't like being tired and sleepy. So I consistently get 8 hours of sleep at night. I don't see that it has any effect on my appetite.

I've definitely noticed this. Sometimes my job requires me to work long hours and I get very little sleep for weeks on end. I've noticed that I become ravenous during this time! However, I also have never gained weight during these times and even lost some (even before I did low-carb). I think long-term sleep deprivation is very hard on my body and I actually need those extra calories.

I had a job where I was constantly sleep deprived and I gained an awful lot of weight. I think it was because I found often the only way I could stay awake during boring sales meetings was to eat.

Thinking about it some more, I remember that I would start craving fat and protein so badly, and I was so exhausted that I lost my willpower to resist and ate more of these "bad" foods. maybe that's the real reason I would often lose a few pounds during these times.

All I know for sure is that during the period of time I had severe insomnia which included sometimes not sleeping at all for up to a week in time, my weight ballooned up and up and up.

This was reported on the national news this morning.

My take on it, is that the researchers are trying to make it fit the latest fancy explanations on hunger and overeating, by focusing on leptin and grelin. Leptin being up, is that a cause or an effect? How elevated is it? What mechanism is involved in its elevation? I think much of science is myopic in focusing too quickly on the minutia of the problem. I think they would have better spent their research dollars, conducting a larger/longer study just to show that the phenomenon is actually valid. Rather than waste money on bloodwork to show the "cause", which at best will be a correlation. Just the fact that they were looking at this so early in the process, indicates that they are dying for this to be the mechanism. What happens when the next hormone is discovered? What would have happened ten years ago before leptin and grehlin were discovered? They would have looked at insulin or something, and made the same correlations and concluded the same about that hormone.

To me the simple explanation is that when you are up four more hours in a day, that is time for one more full meal and laybe a snack on top of that. Plus the difference in metabolism between waking and sleeping, would result in a greater caloric need.

I completely agree that sleep deprivation has bad effects on the human body. We are as adapted to sleep at night, as we are to eat a low carb diet. Doing anything that is contrary to our natural existence, is really asking for trouble.