My dad is in his mid fifties, around 230 pounds, probably 5'10, and has a bad back. He can't lift weights, but he does go on walks every day to get some exercise in. I've been pouring over a lot of the dieting articles here and on berardi's web site and I'm trying to get all the literature I can to provide him with some solid information. It's going well so far, but is there any specific literature you could recommend for his particular situation? He's always been able to attain temporary success (dropping 40 lbs+) with those gimmick diets (Atkins, etc), but it always comes back. Lifestyle change is obviously going to be a key ingredient to success for him. Suggestions?