If you ask any avid yogi why they love yoga so much, weight-loss and calorie burn would probably be pretty far down the list. While you don't want to take away from the mind/body connection people flock to yoga to experience—admit it—you are a little curious how many calories your favorite yoga class is scorching. And if you are on a weight-loss plan, being informed on just how many calories you are expending can be the key to your success. There is no way around it. Yoga is as an amazing full-body workout— but the intensity can vary based on which class you take, from gentle and relaxing Hatha yoga to sweat-dripping-off-your-nose hot Bikram. So which classes burn the most (and the least) amount of calories? The answers may surprise you. "If the method to test caloric expenditure was only based on heart rate, then Bikram and other hot yoga classes might top the charts as the styles of yoga that burn the most calories," explains Jill Lawson, founder of Jill Lawson Yoga. "But while a higher heart rate does correlate with a higher calorie burn, other factors can play a role in increased heart rate without the corresponding caloric expenditure."