The problem I noticed with IF or other "diets" which don't track calories in some way, is that people may tend to eat a lot more once they start doing physical

The problem I noticed with IF or other "diets" which don't track calories in some way, is that people may tend to eat a lot more once they start doing physical activity, negating the weight loss benefit or gaining too much fat. The method I recommend nowadays is to keep your diet as constant as possible, then replace meals or snacks with protein rich, lower calories alternatives until you're satisfied with your protein intake (depending on your weight) and you hit a maintenance diet and , as in your weight doesn't change averaged over two weeks, while doing your normal training regimen (which should include some incremental resistance training for muscle gaining or preservation and some cardio for heart health). Then you have the choice of adding a 200 calories protein rich snack if you're trying to build muscle, removing a snack for 200 calories (if you can manage that) or adding some daily cardio consuming an extra 200 calories (like a 20m cardio class, 2x20 minutes walk, a martial arts class, gymnastic skill-work). You should always weight your self to keep track of things. Eventually you'll weight will stabilise to a new low or a new high and you can go through the process again. In this way, you don't really count calories, you just roughly know that you'll have a few eggs for breakfast, some pasta for lunch, meat or fish for dinner.