Ever tried to have only one or two potato chips? You probably didn't succeed. Why is it that we can be meticulous about our servings of veggies and proteins during meals, but then burn through a bag of chips without noticing.
Researchers at Cornell University's Food and Brand Lab think it's because you need a stop sign. Literally.
As part of a small study published in this month's issue of the journal Health Psychology, researchers served tubes of Lays Stackables to two groups of college students (98 students in total) as the students watched video clips in class. Some of the tubes had an edible "stop signs" — chips dyed red — placed at intervals of either seven or 14 chips.
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While the students weren't told what the red chips were supposed to represent, the students with "stop signs" ate 50 per cent fewer chips than the rest of the group. They also had a much better idea of exactly how many they'd eaten.
"I wonder whether the stop sign made them more mindful of what they were actually doing, that they were eating," says Thornhill-based registered dietitian, Eva Vera Marie Loewenberger.
She says we tend to increase our consumption when eating is simply an accessory to another activity, like watching TV or a movie.
"To stop and be mindful of your food, and enjoy the food, and actually pay attention, that's what's important," she says.
He says we tend to eat what's put in front of us.
"An increasing amount of research suggests that some people use visual indication — such as a clean plate or bottom of a bowl — to tell them when to stop eating," he tells Cornell University's Chronicle Online.
"By inserting visual markers in a snack food package, we may be helping them to monitor how much they are eating and interrupt their semiautomated eating habits," he adds.
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Another trick is to control your portions by not eating directly from a bag of chips, or a tub of ice cream, say, but to serve yourself in a bowl, explains Rita, a registered dietitian with Eat Right Ontario.
"As long as we're not eating out of a container where we lose track of the amount we're eating, then that helps with controlling portions," she says.
But portion sizes have been increasing over the years. The U.S. Centers for Disease Control and Prevention has recently shown that average servings of fast-food fare like fries and hamburgers are now three times as big as they were in the 1950.
And this doesn't just happen when we're eating out. Our idea of a proper portion of food has expanded at home too.
Rita explains that plate sizes a few decades ago used to be about eight inches in diameter, whereas today they are around 10 inches.
"The larger your plate, the more you fill it," she says.
And while you used to get your juice in a restaurant juice glass that was 125 milliliters, she says, "You can't even find those glasses anymore. That's a serving of juice — not an Everfresh bottle."
So you might not be able to eat just one or two chips, but maybe by applying some food dye, you can help pace yourself. Or, until the industry adopts edible stop signs, you can serve yourself in a bowl. Preferably a small one.
Watch the video below about why cheese is addictive.