Lack of sleep boosts food purchases the next day

Howard LeWine, M.D.

Chief Medical Editor, Harvard Health Publishing

Savvy shoppers know that it’s a bad idea to shop for food when they are hungry. It’s a formula for filling your cart with high calorie foods, and likely spending more money than expected. Shopping while sleep deprived may have the same effect.

That finding comes from an interesting experiment done by a team of Swedish researchers. They asked 14 men to go grocery shopping twice—once on the morning after a good night’s sleep, the other on a morning after a night of no sleep. All were given the equivalent of $50 to spend, and were asked to buy as much as they could out of a possible 40 items, including 20 high-caloric foods and 20 low-caloric foods. To make sure the men weren’t hungry, they were fed a solid breakfast before grocery shopping.

The men bought more food, and more high-calorie foods, the morning after sleep deprivation than after sleeping well. The results were published yesterday online in the journal Obesity.

We’ve known for some time that not getting enough sleep is linked to weight gain. It’s possible that shopping may contribute to this phenomenon. Lack of sleep may contribute to weight gain via other possible mechanisms. Too little sleep may

  • slow metabolism
  • prompt cells to store carbohydrates as fat rather than use it for energy or burn it off as heat
  • cause cells to not respond as well as they should to insulin. That increases the level of sugar and insulin in the bloodstream, which can lead to weight gain.
  • lower levels of leptin, a hormone that suppresses appetite, and increase levels of ghrelin (GRELL-in), an appetite-stimulating hormone.

It’s interesting that the researchers chose men rather than women for this experiment. Perhaps in Sweden, where the study was done, men do more of the grocery shopping. In the United States, we certainly need to see if the results will be the same in women.

Putting it into practice

For years, research on weight gain and obesity has focused on genes, foods, diets, and physical activity (or the lack of it). This study from Sweden, along with many others, are showing that our behaviors also play important roles in weight maintenance and weight gain. A good example of this work is the research conducted by Cornell University’s Brian Wansink and colleagues on “mindless eating.”

You can put the Swedish study into practice today. Be aware of how your body responds when you don’t get enough sleep. Whenever possible, shop for food only on days when you’ve gotten at least seven hours of sleep—and don’t go to the grocery store hungry. And when you know you are sleep deprived and tired, focus on mindful eating even more than usual.


  1. John

    Really? I unfortunately suffer from insomnia and actually in the morning the last thing I wanna do is eat. However I know that in order to function properly during the day, you need to have breakfast, so I do force myself to eat something.

  2. Ota Rockaffella

    But, whether by staying up late and just eat a snack will increase obesity?

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