Scientifically speaking, I lost a shitload of weight.
There are lots of variables that helped me drop 120lbs, but the biggest factor has been the significant reduction of added sugar from my diet. See, I'm addicted to sugar -- big time. Quitting it is like having a crazy ex, only if that ex showed up everywhere, all the time. Hell, your friends bring it to parties, and it hides where you wouldn't think, like, spaghetti sauce.
I'm no doctor, so my advice is anecdotal, but I fought obesity for decades and overcame it by simply removing added sugar and unnecessary processed foods from my diet. I'm not perfect, and I still fight the sugar beast. Now, however, I make far better decisions, and I continually educate myself and apply what I've learned. Sugar is a tough monster to battle, so it's best to go in with a strategy. Setting simple goals will provide a framework for a healthier you! I feel like the Mr. Rogers of the formerly fat... come with me, won't you?