Again, I hear ya brother. When I was 210# I was working outside 40 hours a week doing landscaping/trail maintenance and whatnot, lifting 3 nights a week, and going swimming maybe 2-3 times a week. I was eating like a horse but still in the best shape of my life. At 6'4" I wasn't what you'd call a big burly guy by any means, but I was stronger than I really needed to be and more importantly, I felt and slept great.
Turns out, eating the same but standing in front of a bench or sitting in front a computer all the time doesn't work quite as well
I don't believe in "diets" per se, and neither do most doctors (except the ones trying to sell you complicated "plans" and "miracle pills"

). It's fairly simple really... Eat less crap. Eat more lean protein and a lot more veggies. Drink plenty water. Get up and move around. Lift something other than a fork on a regular basis.
Unless there are other medical issues, that pretty much always works.