Why People Overeat

Public campaigns to prevent obesity have focused on nutritional guidelines, diets, and food labels with nutritional information. These efforts assume that, armed with proper information and motivation, people will consume fewer calories. This assumption in turn presumes that eating is a conscious act. However, the continued acceleration of America's obesity epidemic despite these efforts has caused researchers to question the assumptions underlying them. In a recent article, RAND Corporation researcher Deborah Cohen explores an alternative assumption: Eating is influenced more by environmental factors than by conscious choice.

Studies have shown that

• people served larger portions eat more food, regardless of other factors
• the amount of food consumed increases as the effort to eat it decreases
• people eat more when sharing meals with others; the larger the group, the more each person will consume
• once people begin eating, they usually continue until the food is gone or until some other external occurrence changes the situation.

Psychologists now have a better understanding of "automatic behaviors," defined as those without cognitive direction or conscious intent. Many human responses to the environment, including eating, can be understood as automatic behaviors. Labeling eating as an automatic behavior does not mean that people cannot control their eating; automatic behaviors can be controlled temporarily. For instance, people can consciously prevent themselves from smiling when amused or frowning when annoyed. But control over these behaviors is limited and hard to sustain over the long term. As a society, we find it hard to accept that eating is an automatic behavior. We tend to blame lack of willpower for failure to maintain a diet, whereas the more likely culprit is our automatic response to cues to eat and the availability of cheap, convenient, high-calorie foods.

If we view eating as an automatic behavior, we should adopt a new response to the obesity epidemic. Instead of educational or motivational approaches to reduce consumption, we should decrease the accessibility, visibility, and quantity of foods to which people are exposed and reduce environmental cues that encourage eating.

Promising approaches include

• reducing portion sizes
• limiting access to ready-to-eat foods
• limiting access to snack foods in schools and workplaces
• reducing food advertising.