Protein
Protein is inarguably the most important macronutrient for human health, and yet it is far under-consumed by the vast majority of people, especially as we age.
Protein is a vital component of all of our tissues. The other macronutrients – fat and carbohydrates – are essentially just different forms of energy.
Guidelines for protein intake are focused on the minimum requirement for protein to maintain nitrogen balance and avoid protein deficiency. The RDA for protein intake is 0.8 grams per kilogram of body weight – sufficient to prevent deficiency but universally known to be insufficient for optimal health (ref).
How much protein is optimal?
There is much debate about the optimal amount of protein intake. Ultimately, it appears that the optimal amount of protein intake for building and maintaining lean muscle mass is approximately 1 gram per pound of lean body mass. (Note: that is not necessarily 1 gram per pound of body weight.)
Optimal protein intake at mealtimes is dependent on meeting the protein threshold. The requirement for triggering protein synthesis is to consume at least 2.5 grams of the amino acid Leucine. That requires at least 30 grams of animal protein, or 60 grams of plant protein. Anything less than that amount of protein does not trigger protein synthesis and thus fails to provide the intended benefit of protein.
Hitting that protein threshold in the morning has the most impact on fat-burning and maintenance of lean body mass (body weight minus fat mass). Hitting that protein threshold in the evening has the second most impact.
Timing of protein intake
While most people tend to skew their protein intake toward the evening meal, there is evidence that a relatively even distribution of protein intake throughout the day results in increased total protein synthesis. Consuming a moderate amount of high-quality protein 3 times a day stimulates more protein synthesis than the conventional strategy of skewing protein intake towards the evening meal (ref).
Quality of protein source
The quality of protein in one’s diet certainly matters, with preference for animal proteins, e.g. meat, eggs, seafood, fish, etc. These high-quality animal proteins provide the most complete nutrition in terms of amino acids and micronutrients. As I tell my patients: If you want to build an animal (e.g. a human body), you need to use animal building blocks. Animal proteins have the ideal amino acid composition to synthesize animal tissues, while plants have an ideal composition to build plant tissues.