The Food Groups. The Food Pyramid

A. The Food Pyramid. In 1956, simple, specific guidelines enabling an American household to plan and consume meals that meet the recommended dietary allowances were established by the USDA in the form of four major food groups— the “basic four” plan. The plan recommended a specific number of daily servings from each group: milk and milk products, meat and meat substitutes, fruits and vegetables, and breads and cereals.

In April 1992, the USDA released the Food Guide Pyramid to replace the basic four food groups as a nutrition education tool. The pyramid provides dietary guidance for healthy American two years of age and older. The predominant message is to eat a variety of foods from each food group in moderate amounts and in proportion to individual nutrient and energy needs. The pyramid also recommends less sugar and fat in the diet and increased fiber. The five food groups depicted in Fig. 1 are:

FIGURE I. The Food Pyramid: A Guide to Daily Food Choices

- bread, cereal, rice, and pasta group (6-11 servings/day);
- vegetable group (3-5 servings/day);
- fruit group (2-4 servings/day);
- meat, poultry, fish, dry beans, eggs, and nuts group (2-3 servings/day);
- milk, yogurt, and cheese group (2-3 servings/day).

The pyramid is completed with fats, oils, and sweets, to be used sparingly. It is important that people include beverages when reporting food consumption. Among the other educational messages of this pyramid are that some food from each of the major food groups should be eaten every day but that the range of servings may vary, that no one food group is more or less important, and that fat and sugars may be naturally occurring in specific foods or added as such. The pyramid does not tackle the problem of defining portion size. The major nutrients provided by each group are shown in Table II.

Individuals must select meals and snacks from each group to obtain all essential nutrients that are not distributed evenly within each group. Thus, servings of fruit should include one vitamin C-rich food daily and servings of vegetables should include one vitamin A-rich food every other day. While adhering to the food pyramid plan, total nutrient intake can vary widely depending on age, sex, size, and activity level of an individual. At the least, the minimum number of servings in each range should be consumed daily.

The lowest range of servings provides about 1600 calories and is adequate for elderly persons and sedentary women. The middle range provides about 2200 calories and is adequate for children, teenage girls, active women, and inactive men. The maximum serving range provides about 2800 calories and can be used as a guide for teenage boys, active men, and very active women (Table III).

B. The Food Groups. I. Milk, Yogurt, and Cheese. Milk is a good source of many nutrients. Cow’s milk protein is 80% casein. The whey includes lactalbumin and various immunoglobulins. Milk fat is easily digested and varies from 4% in whole milk to 2% in low-fat milk to less than 0.5% in skim milk. The carbohydrate in milk, lactose, is less sweet than sucrose and not readily digested by some ethnic groups and sick people. Calcium, present in large quantities, is generally absorbed more readily than the calcium in other foods (Table IV). Milk contains minimal iron and is a useful source of riboflavin and nicotinic acid. Its low ascorbic acid content is destroyed by pasteurization. Vitamin D is generally added to milk.

The fat content of cream varies from 10% in half-and-half to 35% in whipping cream. The fat content of evaporated milk may vary, while condensed milk has added sugar. Skim milk contains the protein, calcium, and B vitamins in the original milk without fat and with less cholesterol. Yogurt is a nutritious and convenient food with variable fat content.

Most cheese is made from milk clotted using rennet, and contains the same protein and fat as milk and many of the other nutrients. Most cheeses contain 25-35% protein and 16-40% fat, and are rich in calcium, vitamin A, and riboflavin.