Study: French Eat Rich Foods and Stay Thin, And Key Is Portion Size

The French can eat richer foods and remain thinner than Americans because their portion sizes are much smaller, according to a study reported in the September issue of Psychological Science.

Researchers at the University of Pennsylvania and the Centre National de la Recherche Scientifique (CNRS) in Paris reached this conclusion after comparing the size of restaurant meals, single-serve foods and cookbook portions in both countries.

The French paradox has long stymied American dieters and scientists, puzzled by the ability of the French to remain trim while downing buttery croissants, creamy brie and decadent pastries, according to the researchers. Just 7 percent of French adults are obese, compared to 22 percent of Americans, and the mortality rate from heart disease is significantly lower in France.

The researchers weighed portions at 11 comparable pairs of eateries in Paris and Philadelphia, including fast-food outlets, pizzerias, ice cream parlors and a variety of ethnic restaurants. They found the mean portion size across all Paris establishments was 277 grams, compared to a mean in Philadelphia of 346 grams -- 25 percent greater than in Paris.

In just one of the 11 comparisons, between Hard Rock Cafes in both cities, were the Parisian portions larger. Three other international restaurant chains consistently served larger portions in the United States, and Philadelphia's Chinese restaurants served meals that were on average 72 percent heftier than those served by Chinese restaurants in Paris.

"Many studies have shown that, if food is moderately palatable, people tend to consume what is put in front of them and generally consume more when offered more food," Rozin said. "Much discussion of the 'obesity epidemic' in the U.S. has focused on personal willpower, but our study shows that the environment also plays an important role and that people may be satisfied even if served less than they would normally eat."

Extending their approach to single-serve foods sold in supermarkets, Rozin and colleagues found 14 of 17 items studied were larger in American stores. For example, a candy bar sold in Philadelphia was 41 percent larger than the same product in Paris, a soft drink was 52 percent larger, a hot dog was 63 percent larger and a carton of yogurt was 82 percent larger.

"The French paradox is only a paradox if one assumes that dietary fat is the major cause of obesity and cardiovascular disease," said study author Paul Rozin, professor of psychology at the University of Pennsylvania.

"However, recent studies suggest that the importance of fat intake as a risk factor has been greatly exaggerated," Rozin added. "While the French eat more fat than Americans, they probably eat slightly fewer calories, which when compounded over years can amount to substantial differences in weight."

Other sources: University of Pennsylvania