A Creative Study Shows The Cost Of Going to The Market Tired
Imagine you just pulled an all-nighter studying for an important exam, worked a double shift through the night, or were up all night with a child who has the flu. The next morning, you find yourself hungry and suddenly remember there’s only a lone jar of mustard sitting in your fridge so you decide to stop at the grocery store to stock up for the week.
Nicole Avena, Ph.D., is a research neuroscientist and an expert in the fields of nutrition, diet, and addiction.
Editor: Muhammad Talha
Stop!
Step away from the automatic doors, maybe grab a healthy bite out, and then embark on this mission afresh after getting some rest.
Why?
What are the possible perils of going to the supermarket when you really belong in bed? Researchers in Sweden asked just this (more or less) in a 2013 study published in the journal Obesity. They asked men to imagine that they must “stock up” for the next few days in a mock supermarket (consisting of 40 high- and low-calorie items) after either one night of sleep or one night of total sleep deprivation [1]. Participants were given an identical budget and were required to use all of it during the task. Also, prior to shopping, each was given a breakfast of 650 calories.
The Result?
In the simulated supermarket experiment, participants purchased significantly more calories following a night of total sleep deprivation than after a night of sleep. Importantly, the researchers point out that while several other studies (though not all [2]) have shown increased food intake following sleep deprivation [3-6], studying food purchasing behavior is important because food shopping has potentially longer-term consequences for food intake (though whether people actually eat more calories as a result of how much they purchase remains uncertain).
To lend insight into the possible mechanisms that may link sleep deprivation with buying more calories, the researchers also measured levels of ghrelin, a hormone that stimulates hunger. In this study, ghrelin was increased in participants the morning after sleep deprivation; however, the levels of this hormone were not statistically related to how many calories participants purchased. This may indicate either that this hormone is not directly influencing this behavior or that there may have been too few participants enrolled in the study to detect an effect.
It has also been proposed that we may need to take in more energy (in the form of calories) when sleep-deprived in order to fuel the additional activities we may engage in while we are awake [1]. However, research into this hypothesis is mixed, with some studies showing increased energy expenditure following sleep deprivation [7], others finding no increase [5], and still, others showing that though energy expenditure was increased following insufficient sleep, calorie intake exceeded what was needed to establish energy balance [4]. However, the precise conditions of sleep deprivation vary between studies. It is also worth noting that sleep deprivation has been linked to poor decision-making [8], which may extend to decisions made when food shopping.
So, the next time you’re considering a grocery run after pulling an all-nighter, try to sneak in a nap first. And if you absolutely have to go shopping when you’re not at 100 percent, try preparing a list beforehand so you’ll have a guide to navigating the market and maybe less likely to act on impulse. As it turns out, being a smart shopper isn’t only about getting a good deal but also involves making sure that internal factors—like our sleep, mood, and hunger levels—don’t influence the products we buy.