Yoga helps to burn calories, but I think It is difficult to perform yoga asanas for fat people. The persons who have too much weight can't perform yoga easily, but yoga helps us to be fit and slim. Yoga makes our body and mind healther and disease free. Yoga Asanas will also help us not to get extra fat and weight. But I don't think yoga is adviseble for peopel to get weight loss. Even the normall people also find difficult to perform yoga , it takes so much of time and patience to get the full asana.