First of all, it is impossible to do these two things at the same time. In the process of reducing fat, it is not only impossible to gain muscle, but also to lose muscle. It is difficult to lose fat in the process of gaining muscle, because of high calorie intake, so lose fat first and then gain muscle shape.

Reduce fat: control calorie intake less than consumption, and supplement protein appropriately. In short, eat less if you can.

Muscle gain: calorie intake is greater than consumption, and protein should be supplemented in large quantities. On the premise of ensuring strength training, eat once every three hours and eat as much as you can.

These two kinds of protein are mainly skinless chicken and fish, and beef is more difficult to cook, digest and absorb than the former.