Right-sizing meal portions

WASHINGTON -- Call it the alter-ego of super-sizing.

Researchers infiltrated a fast-food Chinese restaurant and found up to a third of diners jumped at the offer of a half-size of the usual heaping pile of rice or noodles, even when the smaller amount cost the same.

Giant portions are one of the culprits behind the epidemic of bulging waistlines, and nowhere is portion-creep more evident than in restaurants with French fry-heavy meal deals or plates overflowing with pasta. Now scientists are tapping into the psychology of eating to find ways to trim portions without people feeling cheated.

"The small Coke now is what used to be a large 15 years ago," laments psychologist Janet Schwartz, a marketing professor at Tulane University who led the Chinese food study. "We should ask people what portion size they want," instead of large being the default.

Restaurants are paying attention, says prominent food-science researcher Brian Wansink of Cornell University. His own tests found children were satisfied with about half the fries in a Happy Meal long before McDonald's cut back the size, and the calories, last year. "We'll be seeing some very creative ways of downsizing in the next couple of years," predicts Wansink, author of "Mindless Eating."

But let's call it "right-sizing," says Duke University behavioral economist Dan Ariely. Right-size suggests it's a good portion, not a cut, he says.

Research shows many Americans don't have the willpower to stop before the plate is clean. We shovel food in before the stomach-to-brain signal of "hey wait, I'm getting full" arrives.

So Schwartz and Ariely tested a different approach: limiting side dishes. At a popular Chinese franchise at Duke customers on line pick rice or noodles first, a whopping 10 ounces, about 400 calories. Customers were asked if they wanted a half-order to save 200 calories, and those who said yes didn't order a higher-calorie entree to compensate. Weighing leftovers showed they threw away the same amount of food as customers who refused or weren't offered the option. A 25-cent discount didn't spur more takers. Nor did adding calorie labels so people could calculate for themselves, the researchers report in this month's journal Health Affairs -- concluding the upfront offer made the difference.

Wansink's research also found switching from 11-inch plates to 10-inch plates makes people take less food, and waste less food. The slightly smaller plate makes a normal serving look more satisfying.