Diets of Americans: How Good Are They?

Betty B. Peterkin, acting administrator, Human Nutrition Information Service.

National surveys track the dietary behavior of Americans, telling us what foods people eat and how well their diets conform to some of the Dietary Guidelines for Americans. (These guidelines are discussed in detail in the next article.) And they tell us how diets change over time between surveys.

From two U.S. Department of Agriculture (USDA) surveys the Continuing Survey of Food Intakes by Individuals, 1985 and the Nationwide Food Consumption Survey, 1977-78 diets of more than 1,500 women 19 to 50 years of age in 1985 were compared with diets of an equivalent group of women in 1977. Diets compared were for one day in the spring of 1985 and one day in the spring of 1977. In personal interviews, women in nationally representative samples were asked to recall food eaten on the previous day using similar, but not identical questions.

This comparison of diets in 1985 and 1977 shows how food and nutrient intakes changed during a period of high public awareness and concern about diet and health. It shows change since the presentation of Federal dietary goals in 1977 and dietary guidelines in 1980. Changes are not necessarily a result of increased knowledge and concern about diet. Socioeconomic and other factors also affect food selections. For example, women in 1985, on average, may have been more pressed for time. Compared to 1977, the women surveyed in 1985 were more likely to be employed full time or part time (60 versus 52 percent).

Food Selection

Food selections by women in 1985 and 1977 were alike in many ways. Most women in both years had some food from four major food groups on the day reported. About 90 percent had one or more vegetables or fruits; one or more grain products; and one or more meat, poultry, or fish items. Only about 75 percent selected milk or a milk product in both 1985 and 1977.

Some rather dramatic differences in women's diets, however, are indicated by results from the two surveys, only some of which may be attributed to women's changing perceptions of "what's good for you."

Move to Mixtures. Women reported eating more food as mixtures of two or more ingredients in 1985 than in 1977. For example, the amount of meat mixtures, such as stews, casseroles, sandwiches (including hamburgers), and frozen dinners was up by one-third. Grain mixtures, which include items such as pizza, spaghetti with sauce, and macaroni and cheese, were up over two-thirds. Milk in the form of milk products such as cheese and milk desserts was up one-sixth. These mixtures may have been commercially prepared, made at home, or prepared away from home in a restaurant or other food establishment.

Where's the Meat? As women shifted toward mixtures with some meat in them, they shifted away from eating meat separately. The average amount of beef eaten separately in 1985 was 45 percent lower than in 1977, and pork eaten separately was 22 percent lower than in 1977. These lower intakes in 1985 may be partly made up by the greater use of beef and pork in mixtures. Poultry intakes were about the same in the 2 years while intakes of fish and shellfish, although relatively small, were a little higher in 1985. Like meat, actual intakes of poultry and fish would probably be increased somewhat if amounts in mixtures were added.

On the day studied in 1985, the category within the meat, poultry, and fish group reported by the highest percentage of women was meat mixtures (37 percent). Next highest was frankfurters, sausages, and luncheon meats (25 percent), although the amounts reported were relatively small. Then came those groups of items that were eaten separately: beef (23 percent), pork (20 percent), poultry (19 percent), and fish and shellfish (12 percent). Percentages choosing beef and pork separately were down from 35 percent and 24 percent in 1977.

Foods sometimes used in place of meat at meals such as legumes, nuts and seeds, and cheese were reported by more women in 1985, but average intakes were only a little higher than in 1977. Average intake of eggs in 1985 was down over one-fourth from 1977.

Grain Products Gain. Women chose more grain products, on average, in 1985 than in 1977. Categories of these products showing the greatest intake gain were grain mixtures (up 72 percent) and cereals and pastas (up 25 percent). On the day studied in 1985, the most women (70 percent) selected yeast bread and rolls, followed by other baked goods (53 percent). Cereals and pastas were reported by 32 percent and grain mixtures by 26 percent.

Milk Choices Change. The amount of milk women consumed as milk and in milk products and the percentage of women having milk in some form during the day were about the same in the 2 years. The form of milk consumed, however, changed average intake of lowfat and skim milk was 60 percent higher and intake of whole milk 35 percent lower in 1985 than in 1977. In 1985, 51 percent of the women chose fluid milk, with about one-half choosing whole milk and the other half choosing lowfat or skim milk. Next in popularity was cheese (34 percent), cream and milk desserts (25 percent), and yogurt (4 percent).

No Gains in Vegetables, Fruits. Intakes of vegetables and of fruits were about the same in 1985 as in 1977. In 1985, 83 percent of the women chose at least one vegetable, with 44 percent choosing white potatoes and 29 percent choosing tomatoes. Only 47 percent chose one or more fruits, with 25 percent choosing citrus fruits and juices.

Beverage Intakes Up. Women's average intakes of carbonated soft drinks, of fruit drinks and ades, and of alcoholic beverages were about 50 percent higher in 1985 than in 1977. Coffee and tea showed no change. The percentage of women choosing carbonated soft drinks increased from 42 to 54 percent, equaling coffee in popularity. Regular soft drinks remained the favorite with 36 percent selecting them in 1985, while 20 percent had low-calorie types double the percent in 1977.

Nutrient Intakes

Shifts in intakes of various foods, by themselves, are neither good nor bad. Only the diet, as a whole, can be assessed for nutritional quality. Women's diets were assessed with respect to their content of 28 nutrients. To do this, the nutrient intake from those foods women reported eating was estimated using information on the nutrient content of foods developed by USDA for assessing survey data in 1977 and in 1985. Then the nutrient intakes were compared to the Recommended Dietary Allowances (RDA) for women for the 15 nutrients for which RDA have been set.

RDA are amounts of nutrients considered to be adequate to meet known nutritional needs of practically all healthy persons. To be safe, the RDA are set above needs of most people so intakes below the RDA are not necessarily inadequate. The risk of having an inadequate intake, however, is greater for people with intakes well below RDA.

Vitamin and Mineral Intakes Improve Slightly. Average nutrient intakes by women in 1985 were above the RDA for 8 nutrients: protein, 6 vitamins (A, thiamin, riboflavin, niacin, B₁₂, and C), and 1 mineral (phosphorus). Intakes were below the RDA for 7 nutrients: 3 vitamins (B₆, folacin, and E) and 4 minerals (calcium, iron, magnesium, and zinc). Average levels were 51 to 78 percent of RDA for these nutrients, except for vitamin E, which averaged 97 percent of RDA. Average intakes of vitamin B₆, folacin, calcium, iron, magnesium, and zinc were below RDA for women sorted by income, race, region, or urbanization. Compared with 1977, intakes in 1985 were as high or higher for food energy, protein, and all vitamins and minerals studied. Of the nutrients below the RDA, calcium showed the greatest gain from 69 percent of RDA in 1977 to 78 percent in 1985. Gains in calcium intakes were apparent for women with high, but not low incomes, and for white, but not black, women.

Fat Down, Carbohydrate Up.

Most calories come from fat, carbohydrate, and protein in diets. Women's intakes in 1985 were lower in fat and higher in carbohydrate, both in average grams of fat and carbohydrate and expressed as a percentage of total calorie intake than intakes in 1977. In 1985 the average fat intake in grams was 5 percent lower and the carbohydrate intake 20 percent higher than in 1977. Protein intake was about the same. In 1985 fat in women's diets provided 37 percent of total calories down from 41 percent in 1977. Carbohydrate provided 46 percent of calories in 1985 up from 41 percent in 1977. Awareness that lower fat diets are desirable and some increased questioning by interviewers to get more precise information about fat in the 1985 survey may have influenced the results somewhat toward lower fat diets.

Dietary Fiber Intakes Estimated. Dietary fiber intakes, estimated only in 1985, are considered tentative because of limited information on the amount of dietary fiber in foods. Women's average intakes were 12 grams a day. Intakes were slightly higher for women in high- rather than in low-income households and for white rather than black women.

Sodium. Sodium in diets is difficult to assess. The sodium content of many commercially prepared foods is not available. Also, women surveyed often do not know how much salt and other sodium-containing products they use in preparing foods and at the table. Excluding sodium added at the table, intakes in 1985 were estimated at 2,600 milligrams a day. The RDA safe and adequate range for adults is 1,100 to 3,300.

Eating Practices

The frequency with which women ate, snacked, and ate away from borne changed between 1977 and 1985. Women ate more often in 1985 than in 1977 four times a day was most frequently reported in 1985 and three times a day in 1977. In 1985, 38 percent ate five or more times as compared to 24 percent in 1977.

Snacks were reported by 76 percent of the women in 1985 but only by 60 percent in 1977. In 1985, snacks contributed 16 percent of total calories with carbohydrate providing more and fat and protein providing less of these calories. They contributed 10 to 15 percent of the day's intakes of vitamins and minerals. Snacks contributed 15 percent of total intakes of calcium and magnesium nutrients that were below recommended levels in these women's diets.

In 1985, 57 percent of the women obtained and ate some food away from home, but only 45 percent in 1977. In 1985, food away from home contributed 28 percent of total calories and about the same proportions of protein, fat, carbohydrate, and of most vitamins and minerals. On the whole, the food women ate away from home was of about the same nutritional quality as food they ate at home.