The most important nutrients for people are proteins, carbohydrates, fats and oils, minerals, vitamins, and water. Proteins are made up of amino acids, small units necessary for growth and tissue repair. Protein is the body's most abundant substance except for water and, maybe, fat. Animal foods such as meat, fish, poultry, milk, and eggs are rich in protein. Good plant sources of protein are beans, peas, nuts, bread, and cereals.
Combining plant sources, such as peanut butter with whole-grain bread or rice with beans, provides excellent protein. So does combining plant and animal sources such as cereal and milk or macaroni and cheese.
Starches and sugars are carbohydrates, the main source of the body's energy. Carbohydrates account for about half of the calorie intake for most Americans and four fifths of the calories in diets of African and Asian people. Foods rich in carbohydrate are also the main source of protein for most of the world. Rice, wheat, corn, and potatoes are common rich sources of carbohydrates.
Sugars aren't essential foods. They provide energy but no nutrients. Because of that sugar is called an "empty calorie" food. Occasional sugars aren't harmful to a healthy, but to much sugar can cause tooth decay when eaten between meals, especially sticky snacks that stick to the teeth.
Fats and oils are a concentrated source of energy. Fats in the diet are a must for good health. They make certain types of vitamins available for use in the body, they provide a cushion for vital organs, they make up part of all body cells, and they help to maintain body temperature. Fats also slow aches of hunger because a food mixture containing fat remains longer in the stomach. .
.
Nutritionists classify different types of dietary fats, or fats in food. Saturated fats usually are solid and come from animals .
