I was never huge, though 212 at 5’9" is overweight and approaching the technical definition of obesity. Due to some undesirable side effects of that weight (medical), I’ve been working to lighten up and am already down 24 lbs in 3 months, with a target of 170. It’s tough, and even painful at times, but it really is as simple as making sure calories in is less than calories out. For the doubters, I recommend just starting with meticulous tracking of activity and food consumption without even making any changes. It gets very obvious very quickly what’s happening, which makes it easier to start making changes.
100 pounds lost is amazing. What did you find that worked for you and how long did it take?