Protein, carbohydrate and fat in food are macronutrients that supply energy in the form of calories. The ratio of protein, carbohydrate and fat in each food varies. For example, vegetables are high in carbohydrate and provide no fat with minimal protein, while meat and dairy are higher in protein and fat content. All three macronutrients are essential for health and must be obtained from foods.
Carbohydrate, protein and fat provide energy for the body's daily functions. Carbohydrates and protein provide 4 calories per gram while fat provides 9 calories per gram. These macronutrients also serve to regulate blood sugar, store energy and insulate and protect vital organs.
The daily amount of each macronutrient a person needs to obtain from food depends on an individual's weight, height, sex and age. Pregnant or lactating women need more nutrients overall. The USDA offers an interactive tool to calculate how much of each macronutrient you need based on your personal stats.
Many food choices can meet the daily requirements for carbohydrate, protein and fat. However, some choices provide more health benefits. For example, a can of soda and an orange are both loaded with carbohydrates, but the orange supplies fiber and essential micronutrients, such as vitamin C, while the soda supplies calories without nutrients.
Macronutrients are clearly stated on nutrition labels. Carbohydrates and protein are labeled in grams per serving and as a percentage of daily values. Fat is broken down into four types based on how many grams are in a serving. The four types of fat on food labels include saturated, trans, monounsaturated and polyunsaturated. MayoClinic.com provides an interactive tool for learning how to read food labels. The daily values on food labels are based on a 2,000-calorie diet.
Health organizations such as the Centers for Disease Control and the Harvard School of Public Health recommend choosing "good" food choices for carbohydrates, protein and fat. Good carbohydrates include whole grains that provide fiber and satiety. Beans and lean meats are good sources of protein while nuts and olive oil are heart-healthy sources of fat.