I just got back from 10 days in France. Like John Travolta in Pulp Fiction, I was struck by all the little differences in Europe—how the toilets work, the way roads are designed, and the size of a meal. Wherever I went, the portion sizes seemed much smaller than what I was accustomed to in Philadelphia.
While visiting the École des Hautes Études En Santé (French School of Public Health) in the city of Rennes, I actually met a researcher who had empirically investigated my observation—he had walked around Philadelphia and gone to restaurants, not to eat, but to weigh the content of the food he was served. His efforts contributed to an interesting study, published a decade ago in the journal Psychological Science, which explored whether portion sizes are indeed larger in Philly than in Paris.
First, the researchers compared the weight of identical meals (e.g., pizza, chicken sandwich) at comparable restaurants in the two cities. On average, they found that portions were 25 percent larger in Philadelphia than in Paris. (Their data suggest that the Royale with Cheese in Paris was actually the same size as a Quarter Pounder in Philly, but a "medium" fries was 72 percent bigger).
To obtain a more macro-level perspective of the food ecologies of the two cities, the researchers also systematically reviewed the Zagat guides for Paris and Philadelphia with an eye toward mentions of portion size. They found that the reviews of Philadelphia restaurants were significantly more likely to mention portion size. And these comments were more likely to reference large portion sizes in Philadelphia than they were in Paris (88 percent vs 52 percent). While no Zagat reviews for Paris restaurants mentioned all-you-can eat buffets, 18 did for Philadelphia restaurants.
Lastly, to get a sense of whether Philadelphia's larger portion sizes were a phenomenon unique to dining out, the researchers also compared recipes for similar meals as they appeared in two nationally prominent cookbooks, America's The Joy of Cooking and France's Je sais cuisine. On average, they found that the portions were 53 percent larger in meat dishes, 68 percent larger in soup dishes, and 5 percent larger in starch dishes. But they were 24 percent smaller in vegetable dishes for the American recipes.
Portion sizes have increased dramatically in the United States since the 1970s—increases that have correlated with rises in the obesity (currently about 35% among adults, with substantially higher rates in low-income communities). Correlation does not mean causation, and several other trends, such more time spent in front of TV and computer screens, may also play a role. As a review article in the Journal of Nutrition describes, however, laboratory studies have demonstrated a simple fact: portion size maters; people eat more when you put more food in front of them.
For example, one study found that people ate 30 percent more when presented with a 1000 gram (about 35 oz.) portion of macaroni and cheese than when they were presented with a 500 gram portion. Interestingly, consumers of both portions reported similar rates of fullness after eating, and only 45 percent actually noticed that there was a difference in the size of the portions they were served. Research published just three weeks ago by scientists at Temple and Arcadia universities found that simply giving children larger plates caused them to serve themselves bigger portions
The Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity in 2001 highlighted the need for better consumer awareness about appropriate portion size. Some local health departments are beginning to take action. Consistent with its Board of Health's proposed ban on sugary beverages over 16 ounces , New York City's Health Department has also launched an ad campaign to raise public awareness about portion size. Philadelphia's 3-year-old law mandating nutrition information on chain restaurant menus, the strongest of its kind in the nation, doesn't mention portion size but the hefty measures of calories and fats that are posted often give a sense of it.
Little differences matter. While reducing portion size is not a panacea for America's obesity crisis—the content of the portion (e.g., spinach or corn dogs) matters too, of course—it is one strategy to help make healthier options the norm, not the exception.