For a slim body type, what is the optimal minimum protein intake in grams per kilogram of body weight required to sustain maximal muscle protein synthesis, considering their unique metabolic rate?

Muscle protein synthesis (MPS) is the biological process by which the body creates new muscle proteins, essential for repairing and building muscle tissue. For a slim body type, which typically possesses a higher proportion of metabolically active lean muscle mass relative to body fat, their unique metabolic rate—the rate at which their body expends energy—is generally higher. This higher metabolic rate means their body is constantly turning over proteins at a faster pace, increasing their baseline need for protein to maintain physiological function and prevent muscle breakdown. To sustain maximal muscle protein synthesis, meaning to optimize the body's capacity to build and repair muscle tissue, the optimal minimum protein intake is approximately 1.6 grams per kilogram of body weight per day. This intake ensures a sufficient supply of amino acids, which are the fundamental building blocks of protein, to fuel ongoing muscle repair from daily activities and support the continuous synthesis of new muscle proteins. While consuming higher protein amounts up to 2.2 grams per kilogram of body weight can offer additional benefits for muscle gain or retention, especially when combined with resistance training or during periods of caloric deficit, 1.6 grams per kilogram is widely recognized as the threshold at which maximal muscle protein synthesis is largely achieved and sustained in healthy, active individuals of a slim body type.