Study: Sex Isn't a Proven Weight-Loss Technique

Walking a mile a day for five years won't lead to a 50-pound drop in weight, sex shouldn't count as your cardio exercise for the day and no one really knows if eating breakfast helps people lose weight.

Those are some of the obesity and dieting myths busted by a new study published this week in the New England Journal of Medicine.

Turns out, there have been few studies about many of the weight-related beliefs Americans hold so dear.

Basically, unproven assumptions have been repeated so often for so long, it's hard to separate the scientifically proven conclusions from the old wives' tales.

• Breast-feeding reduces childhood obseity? Uh, no. But that doesn't mean it's bad; there are lots of other benefits to both baby and mother. 
• Sex as exercise? Not so much. One study (apparently the only study these researchers found) done in 1984 concluded a man burns 21 calories during an average roll in the hay, which is the same as if he'd gone for a walk. "Average" is six minutes, by the way, and it appears no one calculated what a woman gets out of that experience.

"The promulgation of unsupported beliefs may yield poorly informed policy decisions, inaccurate clinical and public health recommendations, and an unproductive allocation of research resources," researchers state in the introduction to the study.

A lot of other assumptions are just as likely to be true as they are to be false, according to researchers:

• Snacking causes weight gain.
• Eating and exercise habits are set in childhood. 
• Adding bike paths, jogging trails, sidewalks and parks to communities will help people be less fat.

Check out the tail end of this New York Times article to see the full list of debunked myths.

Looking for some fitness tips that may or may not be scientifically proven? Patch compiled this list from local trainers and coaches.

With all this uncertainty, what dieting truths to you believe in? Tell us in the comment section below.