A new study offers evidence to support what many people have learned for themselves: never grocery shop on an empty stomach.
Researchers found that people who hadn't eaten all afternoon chose more high-calorie foods in a simulated supermarket than those who were given a snack just before online food shopping.
And in a real grocery store, shoppers bought a higher ratio of high-calorie foods to low-calorie ones in the hours leading up to dinnertime compared to earlier in the day.
The researchers said the results may have implications not just for everyday shoppers, but for "food insecure" families, which often don't have the money to buy healthy food - or any food.
For the study, researchers from the Cornell University in Ithaca, New York, conducted a lab study and went out into "the field" to see how hunger influenced food choices.
They asked 68 adults not to eat for the five hours before a late-afternoon appointment. Prior to starting the experiment, the researchers gave half of the participants a plate of crackers to sate their hunger. Then they had all study subjects shop in a simulated online grocery store.
On average, both hungry and sated participants bought eight low-calorie food items, which included certain types of dairy products, meats and snacks.
The hungry participants also bought six higher-calorie items, compared to four purchased by people who'd recently had a snack.
Likewise in their field study, the researchers observed 82 people's purchases in a real supermarket and found the ratio of high-calorie foods to low-calorie foods was healthier between 1 pm and 4 pm than between 4 pm and 7 pm.
The researchers - like myself - recommend that people have a snack, such as a piece of fruit, a small handful of nuts or a serving of yogurt before going grocery shopping to mitigate the effects of hunger. It can also help to do your shopping at hours when you're less vulnerable, such as after lunch versus before lunch.
For people who can't always afford food, the new study shows there may be biological cues as well as practical ones pointing them toward the junk food aisle.
Not knowing when you're going to have food available means that when you do, you're going to choose a high-calorie option, the researchers said - especially when it's the cheapest one.
SOURCE: JAMA Internal Medicine, online May 6, 2013.
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