The Basics
Why Protein Is the Foundation of Good Health
Protein is one of three macronutrients your body requires to function — and it's arguably the most important for maintaining health as you grow older. Unlike carbohydrates and fats, which serve primarily as energy sources, protein is the body's primary building material. Every cell, enzyme, hormone, and immune molecule in your body is made, in part, from protein.
Protein is made up of smaller units called amino acids. There are 20 amino acids in total, and 9 of them are "essential" — meaning your body cannot manufacture them on its own, so you must obtain them through food. Complete proteins (found in animal products and a few plant foods) contain all 9 essential amino acids. Incomplete proteins (most plant foods) provide some but not all.
Quick Conversion
How to Convert Your Weight from Pounds to Kilograms
Since protein targets are expressed in grams per kilogram (kg) of body weight, you'll need to convert your weight if you're used to pounds (lbs).
Interactive Tool
Your Daily Protein Calculator
Enter your weight and select your health goal to find your personalized daily protein target.
What Does Protein Actually Do?
Beyond building muscle, protein performs a remarkable range of functions in the body. It supports immune function (antibodies are proteins), regulates hormones (insulin and glucagon are protein-based), enables enzymatic reactions (digestive enzymes), transports oxygen through the blood (hemoglobin), and helps your body recover from injury and illness. Protein also promotes satiety — keeping you fuller for longer — which makes it an important tool for healthy weight management.
The Aging Factor: Starting in your 30s, the body gradually loses its efficiency at synthesizing muscle protein — a process called anabolic resistance. This means older adults need to consume more protein per meal than younger adults to achieve the same muscle-building response. The solution is not complicated: eat more high-quality protein, more consistently.