Whey protein isolate powder works great as part of a calorie controlled diet. It has the lowest fat content of any protein around. Almost all the fat content of milk is removed during the processing of it to become an isolate.

Furthermore, protein can actually help you in your diet. When you have a carbohydrate heavy diet, your energy levels will peak and fall during the day giving you cravings. Using protein can smooth out these peaks and troughs and stop your body craving fatty foods during the day.