Snooze to Lose

Our society is sleep deprived.  On average, Americans are sleeping one hour less per night than they did 20 to 30 years ago.  The National Sleep Foundation estimates that the average American gets six hours and 40 minutes of sleep on week nights.  The fast-paced American lifestyle and long work days are contributors; in one survey, the National Sleep Foundation found that Americans are spending 9.5 hours on the job, and over 17 hours out of bed.

This lack of sleep is taking a toll on our health, and our weight.  There is a growing body of research showing that a lack of sleep increases your risk of weight gain.  One way it does this is by disturbing your body’s natural ability to regulate appetite.  A recent study published in the American Journal of Clinical Nutrition attests to this.

In this study, men participated in 2 conditions.  In one condition, they got 8 hours of sleep.  In the other condition, they got 4 hours of sleep.   The next day, the men ate as much as they wanted.  Food intake and physical activity were measured, as well as sensation of sleepiness.

The results for food intake are shown in the following figure:

The effects of sleep deprivation on food intake

When the men only got 4 hours of sleep, they ate 559 more calories than when they got 8 hours of sleep!  Their hunger levels before breakfast and before dinner were also greater.

The results for physical activity were interesting.  When the men were sleep restricted, they had higher physical activity levels in the afternoon than when they weren’t restricted.  However, the night after sleep restriction, their activity levels were lower than when they got sufficient sleep.  So there didn’t appear to be any major differences in overall physical activity between the sleep conditions.

Remember that weight gain is a matter of energy imbalance; when you consume more calories than you burn, you gain weight.  The following figure shows the estimated energy balance for the men when they were sleep deprived versus when they weren’t sleep deprived:

This chart shows the amount of calories eaten and burned when you get enough sleep compared to when you’re sleep deprived. “Calorie Balance” is the difference between the two; a positive balance means you will gain weight over time

You can see the men were in energy balance when they got 8 hours of sleep; when the men were sleep deprived, they were in a positive energy balance of 444 calories per day.  If this sleep deprivation was kept up for an entire year, it would result in over 40 pounds of weight gain!

While the sleep deprivation in this study is more than what most people experience, it is still clear that not getting enough sleep can be a problem.  This study is Just one of a growing number of studies showing how a lack of sleep can wreak havoc with your appetite.  You should be getting 7 to 8.5 hours of sleep per night.  Getting enough sleep is critical if you want to lose weight and keep it off.  In this case, if you snooze, you will definitely lose….weight.

REFERENCE:  Brondel, L., et al.  Acute partial sleep deprivation increases food intake in healthy men.  American Journal of Clinical Nutrition .  91(6):1550-1559, 2010

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The link to the study isn’t working.


It makes perfect sense but what the difficult part is trying to get that sleep. Sleep does not come easy for me. Would love to sleep eight hours.

Niels Jørgensen

I think this resonates very much with the experience I have myself: On days where I don’t get enough sleep I find myself craving sugar (in addition to other things such as lack of mental clarity). Congratulations on the new website, I look forward to reading the articles you have made!




James, I will be starting a job that will almost certainly require me to sleep less than 6 hours a day. Is there anything I can do to counter the need for extra food?


Whilst anecdotes don’t constitute evidence, I made this connection myself a few years ago so it’s interesting that a lot of research is coming out now to support the idea.

I realised that on days when I’m particularly behind on sleep and feeling tired, I also invariably have a constant, insatiable appetite, predominantly for carbohydrate-rich foods. Coupled with a lack of energy/motivation for exercise, these periods of sleep loss inevitably lead to weight gain.


I’ve been seeing observational studies on this for some time and my own conclusion was there was a third factor decreasing sleep and increasing weight.

This study falsifies my earlier conclusion : (

They weren’t funded by the makers of Ambien, were they? ; )

Ryan Zielonka


Congrats on the new site. I will be following closely. My subjective assessment concerning food intake on days which I receive less than adequate sleep mimics the findings above. Interesting stuff, I’ll be circulating this post for certain.