Study: Sleep More While Dieting to Lose Fat

In the war against obesity, dieters may find a new ally with respect to simply getting a good night’s sleep.  For those who’re looking to lose weight, sustained weight loss generally requires a combination of a calorie reduced diet along with a regular exercise program.

Research on Sleep and Fat:

New research suggests that adequate sleep may be more important for optimal weight loss that many of us are aware.  Researchers from the University of Chicago and the University of Wisconsin published a study this month which looked at the impact of varying amounts of sleep on weight loss.

Specifically, the researchers included measurements for not only weight loss itself, but actual fat and muscle loss as well.  The Study with the lead author, Arlet V. Nedeltcheva MD, was published in the Annals of Internal Medicine this month.

In terms of the study design, they included 10 overweight, middle-aged,  participants of each gender (7 men, 3 women;  mean age 41 +/- 5 years).  The study participants were essentially confined to a hospital like setting so that their caloric intake and sleep could be closely monitored.

In terms of diet interventions, the subjects consumed a calorie reduced diet composed of approximately 90% of their required caloric intake.  Participants also cycled through two different phases of the study–one of which involved sleeping 8.5 hours per night while the other just 5.5 hours.

Though participants lost weight during both phases of the study (about 6.6 lbs each phase), they lost a greater proportion of body fat when they slept more.  This amounted to approximately 3.1 lbs of body fat during the longer sleep phase compared to just 1.3 lbs during the other phase.  The rest of the weight loss was attributed to lean body mass from muscle tissue and body organs.

Plamen Penev, study director and assistant professor of medicine at the University of Chicago recently told the Health blog:

“Most people go on a diet to lose excess fat…  The medical benefit of weight loss in terms of reducing the risk of chronic disease is all driven by the loss of fat.”

Dr. Penev continued in response to the relationship between sleep and body mass index (BMI) in humans:

“a consistent relationship between self-reported short sleep and an increase of obesity or overweight or increased BMI.”

In terms of the implications of this present study, it suggests that sleep deprivation while dieting can result in loss of lean body mass.  Since lean body mass is related to metabolism, this can make it increasingly difficult to lose weight if you’re sleep deprived.  What’s more is that the sleep-deprived subjects also reported feeling hungrier.  This increased hunger corresponded to an increase in blood levels of  acylated ghrelin, one form of the appetite boosting hormone.

Future studies involving larger sample sizes as well as participants living under real-world conditions would be helpful to confirm the results of this study.  In the meantime, if you’re trying to lose weight, getting an adequate amount of sleep at night could be helpful.

Research suggests that adequate sleeping while dieting may help you lose more fat and retain more lean body mass.

6 thoughts on “Study: Sleep More While Dieting to Lose Fat

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  • October 6, 2010 at 6:31 pm

    Sleeping during the day is very unhealthy.

  • October 6, 2010 at 9:56 am

    In the U.S. we tend to think of working more and sleeping less as proof of strength or success. It’s amazing how many benefits of sleep are being discovered through more research. “Get more sleep” is such an easy rule to follow with such a big payoff!

    • October 6, 2010 at 5:04 pm

      Deb, though more observational than scientific, the majority of my classmates in medical school gained a fair amount of weight (fat) during the school year. The combination of stress and sleep deprivation seemed to have this effect on most, but not all. After summer vacation, not surprisingly everyone looked healthier and fitter.

      With demands on our time, it’s tempting for many to cut into their sleep to get everything done. On the other hand, it tends to also make people less productive–not to mention the other consequences.

      I agree with you about the importance of getting more sleep!


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