The Washington Post has a nice article looking at how effective mandatory calorie labeling at restaurants is at getting customer to eat less. Short answer: Not very. As the Post reports:
Evidence is mounting that calorie labels — promoted by some nutritionists and the restaurant industry to help stem the obesity crisis — do not steer most people to lower-calorie foods. Eating habits rarely change, according to several studies. Perversely, some diners see the labels yet consume more calories than usual. People who use the labels often don't need to. (Meaning: They are thin.)
Below are selected quotations from various experts cited in the article:
"There is a great concern among many of the people who study calorie labeling that the policy has moved way beyond the science and that it would be beneficial to slow down," said George Loewenstein, a behavioral economist at Carnegie Mellon University who studies calorie labeling. In a recent editorial in the American Journal of Clinical Nutrition, he asked: "Given the lack of evidence that calorie posting reduces calorie intake, why is the enthusiasm for the policy so pervasive?" …
"Consumers really should be using this information because it can be helpful to them," said Lisa Harnack, a nutritionist at the University of Minnesota. After completing a study that showed most eaters did not operate as rationally as she expected, Harnack was heartsick. "I was optimistic we would find that people would make different choices based on having more information." …
Research in a fast-food restaurant in King County, Wash., where calorie labeling is also law, found similar results. The stated finding was grim: "Mandatory menu labeling did not promote healthier food-purchasing behavior."
But nannies never give up—if one mandate fails, there are always others to try:
Another recent study shows what really worked was imposing a higher price — by way of a tax — on big-calorie items.
Don't know the study, but another recent study about the effects of a tax on sugary sodas suggests that it won't get fat people to drink them less. Why? Because most fat people already drink diet sodas.
If providing unheeded information doesn't work, perhaps scaring consumers will. In light the FDA's recent imposition of graphic labels on cigarettes, Reason contributor A. Barton Hinkle recently asked in his column on Nanny State Propaganda:
How long before the government places graphic warning labels on junk food?
Not long. Nannies always know best and they never give up.