Optimizing protein quantity, distribution, and quality

Whether you are the type who eats to live or lives to eat, protein intake is a foundational part of nutritional planning to increase or maintain lean mass as you age. Dietary protein provides amino acids, which are essential for building new tissue, repairing old tissue, and conducting basic cellular functions throughout the body. In the human body, protein is formed from 20 different amino acids. Of these 20, nine are deemed “essential” because our bodies cannot synthesize them and must instead obtain them through our diet. 

Unfortunately, the recommended dietary allowance (RDA) of 0.8 g protein per kg body weight per day is only the minimum amount of protein needed to maintain nitrogen balance and is far too low for goals of increasing lean mass and minimizing the risk of sarcopenia, especially as we age and become anabolically resistant. How much protein each individual requires is more complicated and depends on sex, body weight, lean body mass, and activity level, but essentially, if you under-consume protein, your body will use its own lean mass as a source of amino acids, leading to loss of muscle mass. The Acceptable Macronutrient Distribution Range (AMDR) is 10-35% of caloric intake as protein, which is 1.0-3.7 g/kg/d for the average 57-kg woman or 70-kg man. For those who are minimally active, the lower end of this range is probably sufficient to maintain lean mass. However, those who want to increase their lean mass or who partake in moderate or intense physical activity should try to consume higher levels of protein to promote strength and skeletal muscle growth, up to around 1.2-2.2 g protein/kg body weight/day.

In our practice, we aim for the upper half of this range, or about 1 g per pound of body weight (2.2 g/kg body weight/day), but optimizing your increase in lean mass through muscle protein synthesis (MPS) via protein intake is more than a matter of how much protein to eat – it also depends on how that protein is distributed over the course of a day, as well as on protein quality.