7. Sex is a good workout

Well, depending on how you do it.

The researchers cite evidence that sex takes about as much exertion per minute as going for a walk, but lasts on average about six minutes. That adds up to about 21 calories, which isn't such a good workout, but may be good for stress relief.

"Does it make any difference if you do calorie labeling? Does it make any difference if you cap soda size? Does it make any difference if you remove food advertising to children from television?" says Marion Nestle, professor of nutrition at New York University who is not associated with the study.

"Those are the really important things that people are looking at to change the environment of food choice to help people eat more healthfully, and I don't see any of that in here."