Successful cure for obesity?

So theres two kinds of fat: brown and white. Both occur in the body naturally but white fat is the kind that acually make you fat while brown fat makes you skinny. But theres been little research into this. There should be no side effects because it occurs in people all the time, just in small amounts. So why arent pharmacutical companies jumping all over this, considering obesity is rising worldwide? And if i patent some injection/pill treatment now can i make millions?