You are leaving more behind than you think. Not only will you eat less food and drink slower than you do now, but you'll also leave behind lots of unwanted fat. You'll leave behind the look of pity in other people's eyes as you slowly kill yourself with food. You'll have to get used to being able to walk longer distances instead of huffing and puffing from the car to the store. You'll lose the aching joints from carrying too much weight and you'll lose the constant fear that any little pain might be a precursor to a heart attack.
You will have to get used to buying clothes that arent made by Omar the Tent Maker and, heaven forbid, you'll have to give up shopping in the big and tall/plus sizes section. I know that you will miss being forced to accept whatever Omar decides would look good on an obese person...or at least give maximum coverage.
You'll also lose the fear that you won't be able to perform in bed...and sex might actually become fun again. That may make up for a whole lot of glasses of wine. Oh, and you will gain back some length on the equipment, or so I read in the Man's room. I know that won't be an important and exciting side effect!
Most importantly, I know you won't like the feeling that you get from taking control of your life and your health. I'm certain that won't make up for all the things you'll have to give up.
Good luck on your journey!