Almost 70 percent of Americans have been overweight or obese in recent years, and more than 78 million people in the country have been counted as obese.
The problem has many sources, but one of them is obvious: increased portion sizes. We have a lot of evidence that people will eat whatever is put in front of them, even if they aren’t hungry. As portion sizes expand, waistlines expand as well.
According to the Centers for Disease Control and Prevention, the average U.S. restaurant meal is more than four times larger than it was in the 1950s.
Brian Wansink, a Cornell University professor of consumer behavior, helps to explain why portion sizes have such a large effect. He finds that much of our eating is mindless or automatic in that we tend to eat whatever is in front of us. If you are given a half-pound bag of M&M’s, chances are that you will eat about half as much as you will if you are given a one-pound bag.
The good news is that once we isolate the sources of excessive eating, we will be able to identify potential solutions.
Evidence is increasing that lower-calorie servings can be good for business. One reason is consumer demand. Many customers like, and reward, restaurants that provide light options; an easy way to provide such options is to cut portion sizes. Another reason is the increasing practice, often undertaken voluntarily and eventually to be required by the Affordable Care Act, of posting calorie counts on menus. Customers can be surprised to see just how many calories come from the standard portions of their favorite meals. They may not want to switch to a meal they enjoy less, but a smaller portion may suit them just fine. (Parents and dieters, please take note.)
The broader lesson is that obesity levels, in the U.S. and elsewhere, are hardly inevitable. They are a product of the social context in which people’s choices are made. With careful attention to the subtle social cues that lead to excessive eating, we should be able to make a real dent in a serious public health problem. •
Cass R. Sunstein, the Felix Frankfurter professor of law at Harvard University, is a Bloomberg View columnist.