If you just want to trim down, start excersizing a bit more
make sure you're not doing what most programmers do and live off of junk food and red bull (I fell into that trap years ago). You'll be fine.
"Diet pills" are a gimmick to feed of the laziness of the public. There are supplements that work VERY well in cutting fat, but you won't need them unless you want to go into competitions, because the dedication you need to your diet and working out is far beyond what most people will want to do.