March 26, 2004 -- The take-home box: It's your best defense against the huge portions we're served today. That's the message from a group of weight control researchers.
"You can't rely on somebody else to put the right amount of food on your plate, in your sandwich, or in your snack pack," says lead researcher Barbara Rolls, PhD, chairwoman of nutrition at Penn State's College of Health and Human Development, in a news release.
And you sure can't depend on your appetite; it won't put the breaks on eating, Rolls' studies show. People often don't notice they're getting more food, even if they get a double order -- hence the nation's weight control problem.
Her research group looked closely at this issue: the effects of portion size on people's food intake. They found, just as you would imagine, that most people eat everything that is put in front of them.
The Ziti Study
In a cafeteria-style restaurant, on different days, servers gave the 180 customers either a standard or 50% bigger portion of a ziti pasta entrée (the price was unchanged). The meal came with a pesto-stuffed tomato, roll, and butter.
Customers were also asked to complete a "satisfaction card."
Those served the bigger portion ate nearly all of it - an average of 172 more calories than the standard meal. But they didn't eat more of the tomato, roll, and butter.
Whether they ate a normal-size or oversized meal, most reported that the size of the meal was appropriate. Only underweight and normal-weight people who purchased the larger meals rated their meals closer to being too large. The overweight customers rated both portions as equally OK in size. The extra food they ate didn't register as a problem. Weight control didn't factor into their intake.
That study appears in Obesity Research.
The Submarine Study
In this experiment, 75 young men and women were offered sub sandwiches -- 6, 8, 10, and 12 inches long -- on different days.
When served the largest sandwich, women ate an extra 159 calories or 31% more calories; men ate 355 extra calories, or 56% more.
That study appears in the Journal of the American Dietetic Association.
The Snack Study
This time, Rolls gave packaged potato chips to 60 men and women to eat during a day's time. Each package contained a different amount of chips.
No surprise: If people had lots of chips, they ate lots of chips: The women ate an average 184 more calories and men ate about 311 extra calories. They also ate more for dinner later, too, reports Rolls.
This study appears in the journal Appetite.
"These studies show that for a variety of different foods, large portions lead to increased calorie intake," says Rolls.
Just say no: Eat less, share your food, and set some aside to take home, she advises. It's a big step toward weight control.