It really depends and that's because stress is a huge component of weight gain. You think of someone losing weight when they are under stress, but that's not usually the case at all. Lots of people gain weight because the body attempts to protect itself from the stress. In general, there are types of yoga (such as certain forms of Hatha Yoga) that are going to make you sweat and will be good for weight loss theoretically. But so many people have stress as the root cause of their weight gain and any type of yoga will reduce stress. The way it works physiologically is that if you are under stress, eating is one of the easiest ways to calm down, because as soon as you eat serotonin is released into the system and the body goes into what we call the parasympathetic state of being which is associated with relaxation and digestion. It's an intuitive way to relax - to eat something. At the same time, you are not really eating because you are hungry, you are eating because you're stressed - that's a very common thing. So, yes, a person who is overweight needs to sweat, but they also need to learn to deeply relax, so that they have a certain level of calm in the nervous system. Agitation in the nervous system drives compulsive eating.
