Here is an excerpt from a book I am reading:People who take up deep breathing may be surprised to find superfluous fat melting from the waistline, hips, and other places where it is prone to gather. It seems likely that that link between breathing and burning up foodstuffs for energy partly explains this result.
Pranayama improves metabolic efficiency. The combined practice of asanas and pranayama also fosters a muscular feeling tone (kinesthesis) that finds the physical effects of overeating uncomfortable and somewhat reprehensible. This too has a earning on the way Hatha Yoga skins and reshapes the figure. The postures also break up fatty deposits and streamline the body.
– Pg 67, The Complete Yoga Book by James Hewitt