The five main food groups are a central component of the dietary recommendations set forth by the U.S. Department of Agriculture. Food group guidelines were introduced in 1916, more than a decade before the establishment of recommended dietary allowances, or RDA, for the daily intake of calories and essential nutrients. While the food groups have evolved as knowledge in the nutrition field has increased, their function remains the same -- to help Americans make healthy food choices.
Fruits
The fruit food group encompasses a wide range of fresh fruits and fruit products, including dried, frozen and canned fruit, and 100 percent fruit juice. Berries and melons, which tend to be particularly nutrient-dense, are highlighted as important subgroups of the fruit group. While the USDA generally recommends filling half of each mealtime plate with fruits and vegetables, the amount of fruit you should consume each day depends on your age, gender and activity level. Moderately-active men of any age and moderately-active women through the age of 30 should get 2 cups of fruit per day, while moderately-active women past the age of 30 require 1/2 cup less.
Vegetables
The vegetable food group includes an array of fresh vegetables and vegetable products, including frozen, canned and dried vegetables, as well as 100 percent vegetable juice. The main group is divided into subgroups comprised of nutritionally similar foods, including dark green vegetables, red and orange vegetables, starchy vegetables, other vegetables and beans and peas. The purpose of these subgroups is to promote eating a wide variety of vegetables. According to USDA guidelines, moderately-active women and men between the ages of 19 and 50 should consume 2 1/2 and 3 cups of vegetables per day, respectively, while adults over 50 should reduce their daily intake by 1/2 cup.
Grains
The grain food group is comprised of two subgroups: whole grains and refined grains. Whole grains and their products, including brown rice, quinoa, oats, muesli and whole-wheat pasta, tend to be significantly higher in fiber and protein than refined grain products, such as crackers, corn flakes, grits and traditional pasta. Most refined grains have been enriched, however, and are high in B vitamins and iron.
The USDA recommends that at least half of the grains you consume should come from whole-grain sources. Women aged 50 or younger should consume 6 ounce equivalents of grains each day, while those over 50 should reduce their daily intake to 5 ounce equivalents. Similarly, men through the age of 30 need 8 ounce equivalents of grains per day, but men over 30 and under 50 require 7 ounce equivalents, and men over 50 only just 6 ounce equivalents of grains each day.
Protein Foods
Meat, poultry, fish, seafood, eggs, nuts, seeds, soy products and beans and peas make up the protein food group. Although they’re included in the vegetable group for their fiber content and nutrient profile, beans and peas are also excellent sources of vegetarian protein. The USDA emphasizes choosing lean poultry and meat and consuming a variety of protein foods to enhance the overall nutritional quality of your diet.
The USDA also recommends that, for non-vegetarians, at least 8 ounces of protein per week should come from seafood. Through the age of 30, most women need 5 1/2 ounce equivalents of protein per day, while women over 30 should reduce their daily intake by 1/2 ounce. Men aged 19 to 30 need 6 1/2 ounce equivalents of protein each day. Through the age of 50, men require 6 ounce equivalents, while men over 50 should reduce daily intake by another 1/2 ounce.