There are many kinds of protein powder, from high to low in protein purity: Whey Protein Isolation, whey protein and compound protein. Can be used to reduce fat, but if you want to lose fat faster, you should choose Whey Protein Isolation first. As for the use of protein powder, you can drink a little meal replacement in the morning and drink it within half an hour after exercise. If you want to gain muscle after losing fat, you should choose muscle gain powder like MHP, which has relatively low carbohydrate and calories, but relatively high protein, such as bcaa and glutamine. Eat muscle powder after exercise.