WEDNESDAY, May 9, 2007 (HealthDay News) -- Curbing overeating may have more to do with food choices than with how it's portioned out and eaten, a new study finds.
A team at Children's Hospital Boston gave 18 teens a fast-food meal comprising chicken nuggets, French fries and a cola delivered in one of three ways on three separate occasions: either as a single large serving; divided into four portions served at one time; or divided into four portions served every 15 minutes.
The authors found that the teens -- four males and 14 females, all of who were overweight -- ate the same amount of food (about 1,320 calories worth, nearly 50 percent of their daily energy requirement) regardless of how it was presented. Importantly, none of the subjects finished the meal they were given, suggesting they ate until they were full, not until they ran out of food.
"It didn't matter if we divided [the meal] into four smaller portions and gave it at the same time, or if we divided it into portions and distributed it at 15-minute intervals to slow down intake," said Cara Ebbeling, co-director of obesity research at the hospital. "They ate the same amount of total calories in each case. So, the conclusion is that portioning and eating rate did not affect calorie intake."
The authors speculate that the nutritional qualities of fast food -- high caloric density, lots of fat and sugar, relatively little fiber and simple tastiness -- explains the subjects' tendency to gorge themselves on it.
The results were published in the May issue of Pediatrics.
Registered dietitian Connie Diekman, director of university nutrition at Washington University in St. Louis and president-elect of the American Dietetic Association, praised the study as "very interesting," "well-designed" and somewhat surprising.
"We long thought that if you control the rate with which people consume food, they would eat less," said Diekman. "So, the fact that the calorie intake is pretty consistent across the three groups was a surprise."
Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern, on the other hand, said she was not surprised. "We have seen this before," she said. "If you put food in front of someone, they will eat it. And the larger the size, the more they eat."
Ebbeling stressed that "portioning," as defined in this trial, is different from "portion control," in which people are offered less food overall. Studies have consistently shown that when offered less food, people tend to eat less, and the current research in no way contradicts that, she said.
Instead, this study was about visual cues: The subjects in the current research were always offered the same amount of food, it was just presented in different ways.
But, noting that the study included just one kind of meal, Sandon did question the authors' assertion that there is something about fast food that drives the subjects' desire to eat more of it. "We cannot conclude anything significant about that from this study, because they didn't compare any kinds of food here," she said.
"What if you gave the kids PB&J sandwiches with fruit? Would you get the same response?" Sandon asked.
Diekman agreed that new and larger studies are needed before firm and actionable conclusions can be drawn. Nevertheless, she said, "It is still a good study to look at from the standpoint of, what kind of food you eat is important to how full you feel."
For more information on healthy eating, visit the American Dietetic Association.