You know you burn calories when you have sex. But did you know how many?

•  Making out, 30 minutes: 230 calories

•  Foreplay, 20 minutes: 87 calories for women, 107 calories for men

• Unclasping a bra with both hands: 8 calories

•  Unclasping a bra with one hand: 18 calories

• Unclasping a bra with your mouth: 67 calories

•  Strip tease: 60 calories

• Oral sex: 100 calories

•  Missionary position, 10 minutes: 250 calories

•  Woman on top, 10 minutes: 300 calories for women, 130 calories for men.

•  Sex standing up: Up to 600 calories for both people.

•  Masturbation: Up to 150 calories per session.

•  Orgasm: Between 60 and 100 calories

So, in other words, instead of doing 30 minutes on the elliptical at the gym (around 335 calories), you can do a strip tease, have sex for 10 minutes, and unclasp a bra with one hand for the same effect!

Should we all cancel our gym memberships now?