As someone who lost 100 lbs (from 278 to around 175)and kept it off, my advice is to stop eating shit food, eat a clean diet (do not go out to eat). Pick a 6 hour window to have your meal(s) and every month over a weekend or your time off take 3 days (72 hours) and don't eat a thing. Wash rinse and repeat. In one year you will lose more weight than you ever thought imaginable. The nice thing is exercise is optional but if you want to then just take long walks as much as you like.

No medication/drugs/gyms.