Have you heard of pranayama? Breathing exersices part of yoga.
There is a pranayama called kapala bhati, which is supposed to help you lose weight.

I have been doing it on and off, so I cannt actually tell u if I lost weight cause of it. I know people who have, I can feel the heat when I do it, I am sure it burns a lot of calories.
you will have to learn it in a yoga class or from someone who knows how to do it, rather than online.