You are very accurate in that assessment. I read some stats, sorry I don't recall who did the studies, which said that even intense power yoga only burns around 280 calories per hour. This was termed "mild aerobic excercise" or something to that effect, and was well below activities like jogging, swimming, or vigorous hiking in terms of weight loss calorie burn. That said, yoga is great for overall health, and I think that a healthy body will get to and stay at a healthy weight with much more ease! So, diet and preferably some sort of more vigorous aerobic excercise would be a good supplement.

Good luck!

Jeff