Dietary protein

Dietary protein is the nutrient the body uses mainly to repair and build tissue, though some is burned for energy.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.} Like carbohydrate, it provides 4 calories per gram.^{2International Personal Trainer Academy, Certified Personal Trainer Textbook, p. 486.} Protein requirements rise when a client’s calorie intake or stored energy falls.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.}

The RDA of 0.8 g/kg of body weight per day is intended to prevent deficiency in healthy sedentary adults, rather than improve fitness or body composition.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.} The NSCA gives athletes a general range of 1.4 to 2.0 g/kg per day and says 1.6 g/kg per day optimizes resistance training results for most people.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.}

In practice

An upper-end target of 2.2 g/kg per day can suit clients seeking maximum strength or muscle, including those in a calorie deficit, since higher-protein diets may blunt appetite.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.} Clients getting most of their protein from plants need more because the standard requirement assumes high-quality sources such as meat, fish, dairy and eggs.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.}

The NSCA says intakes above about 4 g/kg per day aren’t indicated for clients with impaired kidney function, low calcium intake or restricted fluids; it describes concerns about high intakes in most healthy people as unfounded.^{1Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 125.}

ISSA places prescribing meal plans or supplements outside a trainer’s scope of practice.^{3International Sports Sciences Association, Fast Track Study Guide: Nutrition, p. 1.} Trainers can review eating habits and suggest improvements, with referral to a dietitian for clients with nutrition deficiencies.^{3International Sports Sciences Association, Fast Track Study Guide: Nutrition, p. 1.}