You know the cliché that it’s unwise to shop for food when you’re hungry? New research suggests it’s absolutely true.
Two experiments—one in a lab, another that tracked actual supermarket purchases—provide evidence that famished food shoppers don’t necessarily buy more items, but the ones that end up in their carts are less likely to come from the health-food or produce aisles.
“Even short-term food deprivation can lead to a shift in choices, such that people choose less low-calorie, and relatively more high-calorie food options,” write Cornell University food psychologists Aner Tal and Brian Wansink. They describe their study in a research note published in the journal JAMA Internal Medicine.
“People who shopped at hours when they were more likely to be hungry tended to buy less low-calorie foods proportionate to overall purchases.”
Their laboratory experiment featured 68 people of various ages (71 percent were women) who met in groups of six to 12 during a weekday afternoon. All were asked to avoid eating for five hours before the experiment. Half the groups were provided with a plate of Wheat Thins crackers during the course of the afternoon “and instructed to eat enough to no longer feel hungry.”
Later in the afternoon, all the participants went online to visit a simulated virtual grocery store. They were presented with a variety of options, including lower-calorie items such as fruits and chicken breasts, and higher-calorie ones such as candy and red meat.
The researchers report that hungry and satiated participants chose roughly the same number of low-calorie items, but those with empty stomachs bought more high-calorie food. This trend applied across a range of categories: the hungry were more likely to choose higher-calorie meats, snacks, and dairy produces.
In an attempt to replicate these findings in a real-world setting, Wansink and Tal tracked the supermarket purchases of 82 people “at different times of the day, when an earlier study had indicated they were most likely to be full (1 to 4 p.m.) or hungry (4 to 7 p.m.).”
They found the ratio of high- to low-calorie food purchases shifted over the course of the afternoon, with later shoppers choosing a higher proportion of high-calorie items.
“This difference emanated mostly from a decrease in healthy items (for early-evening shoppers),” they report. “People who shopped at hours when they were more likely to be hungry tended to buy less low-calorie foods proportionate to overall purchases.”
Given the difficulty so many people have losing weight, these results could have “important health implications,” the researchers write. Obesity is a complicated issue with many causes, but this research suggests one factor may be the way so many of us plan our afternoons: Eating nothing after lunch, then stopping at a store on the way home from work.
If you are trying to eat healthier, that particular way of organizing your day appears to be self-defeating. The safe way to go to Safeway is after a snack.