Protein is broken down into three groups of amino acids: 

• Essential amino acids  - cannot be made by the body and must be supplied by food
• Nonessential amino acids - made by the body from essential amino acids or in the breakdown of proteins
• Conditional amino acids - those that are needed in times of bodily stress and illness

A well-balanced diet provides the recommended amount of daily proteins as dependent on your age and health. Healthy forms of proteins include beans, white meats, lean cuts of beef or pork, fish and shellfish, nuts and seeds, tofu and other soy products, and low-fat dairy products.