NOTE: On September 19, 2018, JAMA Internal Medicine retracted several studies that included Brian Wansink as a co-author because of concerns regarding the studies’ scientific validity. This study was one of them.
Going grocery shopping when you’re even a little bit hungry is not a good idea — if you want to resist filling your cart with high-calorie junk food, that is.
That’s the key message from a study published Monday in the print edition of JAMA Internal Medicine.
Past research has shown that people tend to seek out higher-calorie foods when they haven’t eaten for 18 hours or longer. But less was known about how shorter periods of fasting — say, the hours between lunch and dinner — affect food choices.
Study details
For this new study, two marketing researchers, Aner Tal and Brian Wansink, at Cornell University in Ithaca, N.Y., asked 68 paid participants, aged 18 to 62, to refrain from eating anything for five hours prior to the study, which took place between the hours of noon and 5 p.m. on two weekdays.
The participants were randomly divided into two groups. One of the groups was given crackers and told to eat as many as necessary to feel full. The other was not given anything to eat.
All the participants were then sent on a virtual shopping spree though an online grocery store. The store included a mix of low-calorie items, such as fruits, vegetables and chicken, and high-calorie ones, such as candy, salty snacks and red meat.
The researchers found that the hungry shoppers selected 23 percent more high-calorie foods than did the group that had filled up on the crackers (an average of 5.72 vs. 3.95 items).
But, interestingly, the hungry shoppers did not select more food items overall — just a greater proportion of high-calorie ones.
‘Real world’ results
The researchers then repeated the experiment in a “real world” setting. They observed the food purchases of 82 participants as they shopped in a grocery store during times when they were either most likely to be full (after lunch, from 1 to 4 p.m.) or most likely to be hungry (before dinner, from 4 to 7 p.m.).
The late-afternoon-early-evening shoppers tended to buy fewer low-calorie items in proportion to their overall purchases than the after-lunch shoppers (an average of 2.48 versus 3.96 items).
“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,” conclude the study’s authors. “Given the prevalence of short-term food deprivation, this has important health implications. It suggests that people should be more careful about their choices when food-deprived and possibly avoid choice situations when hungry by making choices while in less hungry states (eg, by eating an appetizer before shopping).”
Just make that a healthful, low-calorie appetizer.
