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. He is the former administrator of the White House Office of Information and Regulatory Affairs, the co-author of "Nudge" and author of "Simpler: The Future of Government," to be published in April.