I am 61 years old in A-fib retired/disabled 6' 570lbs and worked 6 day's a week from 1974 to 2008 and now I have to make a major change, I have been on Nutri-system, Weight watchers, Opti-fast and every other diet under the sun. I end up losing for the first three or four weeks then I celebrate and go right back up plus. The most I have lost was in 2008 when I ended up in the hospital with a-fib and lost 140lbs in 6 weeks, my weight was 580 I went down to 440 and felt like a million dollars, eventually it all came back on. I refuse to get the Gastric bypass because I know a lot of people that had it and gained their weight back, most of them are sick. This may be one of my last shots of losing weight, I was told to try this Keto diet, any suggestions from people that have been on it would be helpful.