Can you build muscle on a calorie deficit with enough protein?
Although it may be possible to build some muscle in a calorie deficit, this is not optimal for maximal muscle growth. It is possible to derive the necessary energy needed to build muscle mass from the body’s energy reserves, such as body fat (1).
To do so, you must provide the body with a muscle-building stimulus through progressive resistance training and eat adequate amounts of protein >2g/kg body mass (2&3).