October 19, 2004

Larger Portions Contribute to Obesity Problem

Print More

When young adults are served larger portions of food they are more likely to overeat, found a recent study conducted by Prof. David Levitsky, nutritional sciences and psychology and Trisha Youn ’01. The research supported a previous study by New York University professors which proved that expanding portion size is responsible for America’s growing obesity problem.

Levitsky views the results of his research as promising from a health and nutritional standpoint. The report reads, “[if it is] correct that the increase in portion size is a major cause of the ‘Epidemic of Obesity,’ then it should be possible to stop and possibly reverse this trend toward increased body weight by controlling the size or portions served to the American people.”

To conduct their research, Levitsky and Youn asked 13 undergraduate students to eat a buffet lunch three times a week. Each lunch consisted of bread sticks, vegetable soup, pasta and tomato sauce, ice cream and water. The students were not told that their food intake was being monitored and were instructed to eat as much or as little as they wanted. The following week, the students were split into three groups, with each group being served 100 percent, 125 percent or 150 percent of the food than they had eaten the week before.

Research showed that when the students were served larger portions, they consumed greater amounts of food. The increase in portion size affected the amount eaten for all four components of the lunch. Students who consumed the largest increase in portion size from the previous week — 150 percent — ate an average of 273 more calories per person.

The researchers’ final report, “The More Food Young Adults Are Served, the More They Overeat,” is published in the October issue of the Journal of Nutrition. Levitsky and Youn based their research on the findings of NYU nutrition professors Marion Nestle and Lisa Young, who theorized that America’s obesity problem was linked to a widespread increase in portion size at restaurants and supermarkets. However, neither the NYU professors’ study nor previous nutrition studies showed a link between an increase in portion size and amount of food consumed by young adults, as Levitsky and Youn found.

“I wanted to fill in the gap to show that when you are offered larger portion sizes, you actually eat them,” Levitsky said.

“The epidemic in obesity occurring everywhere is clearly caused by the serving of large portion sizes,” he added.

In a study conducted last year, Levitsky also proved that the “freshman 15” truly exists. During their first 12 weeks on campus, freshmen typically gain 4.2 pounds, with 20 percent of this weight gain coming from the all-you-care-to-eat dining halls. Because Levitsky has shown the relationship between large portion sizes and obesity through his research, he says that education is the key to combating weight gain.

“If [large portions] are one of the causes of obesity, one of the solutions has to be teaching smaller portion sizes,” he said.

To counter obesity, Levitsky has tried to teach students proper portion sizes, while encouraging them to monitor their weight. According to his research, students who monitored their weight regularly were less likely to gain weight than students who did not. Levitsky is also trying to institute weight monitoring in workplaces at Cornell.

Levitsky said that the media pressure for restaurants to reduce portion sizes, like in documentaries such as Super Size Me, is positive because it focuses attention on how easy it is for Americans to overeat.

“The food industry has been stupendously successful at forcing us to eat more than we generally did,” he said. “If [new research] can be forced into action it will cause a decrease in obesity. The cost will be the cost of the food industry, and I fully expect them to put up a big fight.”

Archived article by Olivia Oran
Sun Staff Writer