Proteins—The Basis of Body Structure
Protein = a compound made of amino acids that contains carbon, hydrogen, oxygen, and nitrogen
Of twenty common amino acids in foods, nine are essential
Proteins form key parts of the body’s main structural components—muscles and bones—and of blood, enzymes, cell membranes, and some hormones.
Complete and Incomplete Proteins
Complete protein sources = foods that supply all the essential amino acids in adequate amounts
Meat, fish, poultry, eggs, milk, cheese, and soy
Incomplete protein sources = foods that supply most but not all essential amino acids
Plants, including legumes, grains, and nuts
Recommended Protein Intake
Adequate daily intake of protein = 0.8 gram per kilogram (0.36 gram per pound) of body weight
Acceptable Macronutrient Distribution Range = 10–35% of total daily calories as protein