Ive done the Master Cleanse a few times. I only did it for 3 days or so. The first one was a bit rough. A bit dizzy at times. Felt a lot better afterwards. You can subsitute watermeleon instead. Some recomend two fastings a year.
About 4 years ago, I weighd 230 lbs, 40 inch waist. I was nearing the obese range on the BMI scale. I restricted my diet and walked a bit at work. I came down to 214 lbs after a few years. Still, my glycerides etc. were near diabetic levels. Years before, I was near perfect for all that stuff. Desk jobs will kill you.
I restricted my diet and walked, and also Ballroom dance leasons once a week. They were private leasons, so constant moving. I was droping 2 to 3 lbs a week. I was down to 178 lbs and a 33-34 waist. I stopped the ballroom lessons, eat a bit more, but still walk about an hour a day. I steadily increased weight. I am at 200 to 205 lbs. presently. OT at work doesn't help.
I wouldn't restrict you diet to much. I think the formula is 10x of your body weight. Restrict your diet to much and your body goes into crissis mode. Your metabolism will slow way down. Also, fat is not the evil it is made out to be. Your body needs some amount of fats to functions. It is the type of fats etc. As for a Hamburger, the meat isn't the problem, it is the bun.
One of my friends was/still is way over weight. I told him to stop eating the hotdogs for breakfast etc. Wouldn't listen. Then discovered he's diabetic. Really, adjusted his diet. Not much bread, cookies, sweets etc. Not much white, like rice, breads, sugar etc. He has dropped 50 lbs. Probably need to drop 50 more.
Tom