Fasting Diet

I haven't tried it myself because I wouldn't be able to stick with 600 calories two days a week, but I do know people who have had good success with it, especially where it fits their lifestyle. There is a major pitfall to watch out for though that people often fall into in one of two ways. You need to eat at TDEE for the 5 non fasting days and not 1) whatever you want or 2) on a calorie restriction for faster loss. The 5 days should be nutritionally balanced because 600 calories is not sufficient to get get all of your required daily micro and macro nutrients. As the best way to be sure that you are eating at TDEE is to weigh, measure and count calories it just seems easier to do that all 7 days to me. At the end of the day the 5:2 diet is just another way of putting you into a weekly calorie deficit

Personally I found it too restrictive and ended up doing my 500 calories (for women) in one sitting. I know of colleagues and friends who has tried it with great success, and has lost a lot of weight on it. Each to their own. Just remember, you still need to ensure you do not overeat on the other 5 days, try and eat close to your maintenance, or your result will not be very good and/or you will not get all the nutrients you need. Pre-plan your menus to ensure you do not stray, and good luck.

PS Plan for your 600 calories on your non exercise days.