Sex only burns 21 calories - and other weight loss myths debunked

If you want to lose weight, sex won't help much; study says most people will only burn 21 calories when having sex.

If you consider sex the same as a good workout, think again. You're (sadly) only burning on average 21 calories, according to these researchers.

David Allison, a biostatistician at the University of Alabama at Birmingham, tested the "sexercise" theory - that sex can be exercise - but found that sex lasted only six minutes on average, burning a paltry 20 or so calories.

Despite the many times you've likely heard that sex burns between 100 and 300 calories, that's based on an old, small study, the researchers say.

The findings, published online Thursday in the New England Journal of Medicine, claim that false assumptions like this are part of the reason for the obesity epidemic.

Other misconceptions include the concept that eating a little less and exercising a little more, over the long term, won't produce large, long-term weight changes. Recent data, the authors say, shows that people lose much less weight when they burn it over a longer period of time.

Also while some believe that skipping breakfast can cause weight gain, the research team found that that depended on whether or not people were used to skipping breakfast.

Check out what are the other common misconceptions we have about weight loss and the facts to set you straight: