You don’t burn substantial calories through sex: Weight loss myths debunked

If you’ve been racking up extra hours in the bedroom because you enjoy sex, keep at it, you tiger. If you’ve been racking up extra hours in the bedroom because you believe sex is going be your fast track to abs of steel, you might want to reconsider.

A new study published Thursday in the New England Journal of Medicine suggests you may be better off slapping on your sneakers and hitting the old treadmill.

Researchers at the University of Alabama at Birmingham claim they've debunked the long-held (and very popular) myth that getting frisky between the sheets burns anywhere from 100 to 300 calories.

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Instead, David Allison and his report co-authors found that sex burns roughly the same amount of calories as walking at 2.5 miles per hour -- 21 calories for men to be exact.

“Given that the average bout of sexual activity lasts about 6 minutes,” the report reads, “a man in his early to mid-30s might burn 21 calories.”

To put that in perspective, notes the LA Times, that same man would burn seven calories by watching television for an equivalent amount of time.

The study also tackled several other popular weight-loss myths.

Among the most surprising, they found that physical education classes in school do little to curb the rising tide of childhood obesity, as the classes aren’t long or intense enough to affect real change.

Also, that whole snacking leads to weight gain thing? Overstated, say the authors, who claim there are no high-quality studies to support that theory.

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And if you’re a frequent breakfast skipper, you may have new ammunition to justify your choice. The study found that missing out on the first meal of the day had no significant impact on BMI. It simply depends on whether your body is used to it or not.

While breastfeeding advocates can continue to trumpet the many benefits of mother’s milk, staving off obesity is no longer one of them, say the study's authors.

The LA Times notes that this claim was recently been presented as “fact” by the World Health Organization, although the researchers found “no compelling evidence” that babies who were breastfed had lower obesity rates than babies fed by the bottle.

"The evidence is what matters," says Allison, despite the commonly held “feel-good” ideas many well-meaning health experts have parroted for years.

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However, it should be noted that a number of academics and field experts have called the study’s underlying motivation into question.

Though the study was funded by the U.S. National Institutes of Health, CBC reports that several of the authors received grants from multinational food and pharmaceutical companies, creating concern about potential conflicts of interest.

"It raises questions about what the purpose of this paper is," Marion Nestle, a New York University professor of nutrition and food studies, tells the Associated Press. She suggests that the study may be aimed at promoting drugs, meal replacement products and bariatric surgery as solutions.

"The big issues in weight loss are how you change the food environment in order for people to make healthy choices," such as limits on soda sizes and marketing junk food to children, she adds.