May 6, 2013 at 4:50 PM ET
If you've ever gone grocery shopping while you're hungry, you know the task can be a challenge: Everything looks good.
Now new research confirms that grocery shopping when your stomach is rumbling is probably not a good idea.
To hungry shoppers, high-calorie foods may be more tempting than usual, the researchers said.
In the study, researchers asked 68 people to come to their lab and to avoid eating for five hours before they came. Upon arrival, half of the participants were told they could eat as many wheat crackers as they wanted, while the other half were not given any food.
Both groups of participants were then asked to grocery shop in an online store that offered high-calorie foods, such as candy, salty snacks and red meat, as well as low-calorie foods, such as fruits, vegetable and chicken breasts.
Participants who were hungry purchased more high-calorie products, the researchers found. On average, hungry people purchased 5.7 high-calorie products, while the group that ate before shopping bought 3.9 high-calorie products.
In a second experiment, the researchers, led by Brian Wansink, director of the Food and Brand Lab at Cornell University, analyzed purchases of 82 people in a real-world grocery store. They compared the purchases of those who went shopping between 1 p.m. and 4 p.m. (an "after lunch" period when people are less likely to be hungry) to those who went shopping between 4 and 7 p.m. (when people are more likely to be hungry).
Those who shopped between 4 p.m. and 7 p.m. bought fewer low-calorie products compared with those who shopped between 1 p.m. and 4 p.m. (buying eight products versus 11 products).
"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," the researchers wrote in the May 6 issue of the Journal for the American Medical Association.
The findings suggest "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," the researchers said.
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