Why are so any poor people fat? Because they eat a diet that is largely starch: bread, potatoes, pasta, and other cheap "filler" foods. That stuff turns straight to fat. Our pre-agricultural ancestors did not eat Kraft Macaroni 'n' Cheese; they ate wild greens, wild fruit, fish, insects, and (when they could get it) game. That's the "natural" diet for the human being if there is any such thing.
Again: One should never go on any kind of diet without the advice and consent of one's own M.D.
I started drinking coffee and tea rather than soft drinks. Still some sugar, but much less. I have no sweets during the day. No more vending machine raids at work.
I had started to feel really bad whenever I ate large amounts of sugar, and decided that was a pretty good sign I shouldn't do it.