Protein Calculator

Protein supplies the amino acids the body uses to build and repair muscle, skin, enzymes, antibodies and hormones — functions no other macronutrient can substitute for. Nine of the roughly twenty amino acids used in the body are classified as essential, meaning they cannot be synthesised internally and must come from food.

The official Recommended Dietary Allowance of around 0.8 g of protein per kilogram of body weight is set to prevent deficiency in the large majority of sedentary adults — it is a floor, not a target for anyone trying to build or preserve muscle. Sports nutrition research, including position stands from bodies such as the International Society of Sports Nutrition, has repeatedly found that people doing resistance training benefit from considerably higher intakes, generally in the range of 1.6 to 2.2 g per kilogram, with intake beyond roughly that range showing no further measurable benefit in controlled studies.

Not all protein sources are equivalent. Animal proteins — meat, fish, eggs, dairy — are described as “complete,” supplying all nine essential amino acids in proportions the body uses efficiently. Most individual plant proteins are lower in one or more essential amino acid (commonly lysine in grains, or methionine in legumes), though eating a variety of plant sources across the day generally supplies a complete amino acid profile without needing to pair specific foods at the same meal, a once-common recommendation that more recent research has shown to be unnecessary.

Beyond the daily total, short-term research on muscle protein synthesis — the process by which the body builds new muscle tissue — has found that spreading protein intake across three or four meals stimulates it more effectively than eating the same total amount concentrated into one or two large meals. This is generally treated as a secondary refinement on top of hitting an adequate daily total, not a substitute for it.