Wishful thinking in public health

Jacob Sullum looks at the growing support for mandatory calorie signage in fast food restaurants:

Since they overestimate the demand for nutritional information, advocates of menu mandates also overestimate the impact of making it more visible. "Menu board labeling has the potential to dramatically alter the trajectory of the obesity epidemic in California," the California Center for Public Health Advocacy claims, projecting a weight loss of nearly three pounds a year per fast food consumer. The New York City Department of Health and Mental Hygiene, which began enforcing a calorie count requirement last month, predicts it will stop 150,000 people from becoming obese and prevent 30,000 cases of diabetes during the next five years.

Both estimates are based on a study conducted by New York's health department before the city's menu rule took effect. The researchers asked about 7,300 customers at fast food restaurants in the city whether they had seen and made use of nutritional information, which is typically displayed on posters, brochures, tray liners, or counter mats (as well as on the chains' websites). They also examined the customers' receipts so they could calculate the calorie content of the food they purchased.

This hopeful attitude towards mandatory labelling is a sort of healthcare cargo cult: the practitioners passionately believe that a) people will bother to read the labels, b) that having read, they'll order "better" food, and c) that this effect — should it actually exist — will be permanent.

They'd be just as effective building airstrips.