The Biological Imperative of Dietary Protein
Of all the macronutrients, protein is the only one that is biologically essential for structural repair and tissue maintenance. While carbohydrates are primarily an energy source and fats are an energy storage and regulatory medium, protein is the building material of the body. Skeletal muscle, bones, skin, hair, internal organs, enzymes, neurotransmitters, and immune antibodies are all constructed from proteins.
Proteins are composed of organic compounds called amino acids. There are 20 amino acids used by the body, divided into non-essential amino acids (which the body can synthesize internally) and nine Essential Amino Acids (EAAs). The essential amino acids cannot be created by the body and must be consumed through your diet.
Consuming protein triggers Muscle Protein Synthesis (MPS), the cellular process where the body repairs and builds new muscle tissue. To build muscle, MPS must exceed Muscle Protein Breakdown (MPB) over time, a state known as positive nitrogen balance. Conversely, when protein intake is low or calorie deficits are extreme, MPB exceeds MPS, leading to muscle wasting.