Does sex burn as many calories as a trip to the gym? Reports throughout the years claim it’s possible to burn up to 300 calories during sex.

According to Woman’s Day, a good romp in the hay can burn more than 144 calories per half-hour, and moaning in ecstasy can even burn an extra 18 to 30 calories. Likewise, WebMD claims 30 minutes of sex burns at least 85 calories—42 half-hour sessions can burn enough calories to lose an entire pound. But according to a new study from the University of Alabama at Birmingham, the average person, in fact, only burns about 21 calories during the average sex session.

Why the discrepancy? Well, for starters, biostatistician David Allison found the average sex session lasts just six minutes—no where near the time estimated in other studies. The study which scientifically measured energy output was conducted in 1984 and didn’t even measure womens’ experience. Therefore, the 21 calories in six minutes can assumed to be the amount a man—on top—burns. Based on those figures, in a 30-minute session—if he can last that long—he would burn more than 100 calories—closer to the WebMD report.

Is it safe to assume that a woman on top will burn the same number of calories? According to Woman’s Day, the answer is yes.

If you are on top, try moving your hips like a belly dancer; this feels great and will give you a workout,” said Los Angeles-based sexologist Jaiya Kinsbach. “Also try a position where you squat on top of him and then bounce up and down. This is a great workout for your thighs and butt, and it can burn up to 207 calories in 30 minutes.”

So is the key to weight loss in a man’s stamina? Allison’s report in today’s issue of the New England Journal of Medicine says no—weight-loss fallacies are simply detracting from real solutions to America’s weight problems. Other experts agree.

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, New York University professor of nutrition Marion Nestle told the Associated Press. “Some of the myths they cite are distractions.”