Stu, There is no definitive physiological benefit to fasting. The body has a variety of adaptive mechanisms for coping with periods of lean caloric input and the net result is an overall conservation of stored energy. The reality is, some amount of daily carbohydrate is needed to effectively burn off fat in a healthy fashion. If you fast for a couple of days and then resume your usual diet, you run the risk of a rebound effect to compensate for the prior days' deficits (I agree with MPS's post). I am stunned to admit this, but Marc37 is correct in noting that we eat too much (American more so than other nationalities, but the rest of you are catching up sadly). I'm not too sure I agree with his other thoughts on this matter, but to each his own. There was some controversy over discussion of BMI on a prior post; I'll avoid that topic but will perhaps open a different can of worms with the following: (1) Try to figure out your ideal body weight (there are variety of different ways of doing this, I'll give one example): allow 106 lbs for the first 5 feet in height and add an additional 6 lbs for every addtional inch. This can be adjusted upwards by 10% if you have a larger frame (or reduced by the same amount if you have a smaller frame). (2) Multiply your ideal body weight (not your actual body weight) by 10-15 to approximate your daily caloric requirements. For men, multiply by 10 if you are sedentary AND over the age of 55, or obese; multiply by 13 if you are sedentary OR over the age of 55; multiply by 15 in all other cases. This will give you your ideal daily caloric intake (some athletes will naturally require substantially more calories, but I am directing this to the average person who is trying to lose weight.). (3) A 3500 calorie deficit per week will produce a one pound loss of body fat. So, if you reduce your ideal daily caloric intake (as calculated above) by 500 calories per day then over the course of 7 days you can expect to lose one pound of fat. If you exercise, the resulting caloric expenditure can be included and the expected weight loss calculated (eg. if you eat 250 calories less per day and expend a net negative 250 calories with exercise, the total is 500 calories lost and the rate of weight loss will be the same). Even if you only lose 5-10% of your body weight, you should expect to see an improvement in your cholesterol (and blood pressure or blood sugar problems if any). Remember, fat should be <30% of daily calories (saturated fat <10%) and cholesterol should be less than 300mg per day.