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Economics and Nutrition BENJAMIN SENAUER The disciplines of economics and nutrition provide important insights into the understanding of American eating patterns. Major themes that help elucidate these patterns include the effect of income and prices on diet, efficiency in food consumption patterns, and me conceptual per- spectives provided by the new household economics and by food and nutrition profiles. INCOME AND DIET One of the first factors an economist examines in analyzing food con- sumption behavior is household income, which determines the budget that is available for expenditures and imposes constraints on consumer behav- ior. Income may, therefore, be related to nutrient intake and food con- sumption patterns. income and Nutrient Intake Table 1 presents average nutrient intake levels, as percentages of the Recommended Dietary Allowances (RDAs) (NRC, 1980), for persons in households at four income levels. These data are based on the individual portion of the 1977-1978 Nationwide Food Consumption Survey (NFCS) conducted by the U.S. Department of Agriculture (USDA, 1980) and reflect income levels for that period. Consumption of all nutrients except vitamin A and thiamin appears to increase with income. However, the 46
ECONOMICS AND NUTRITION 47 TABLE 1 Per Capita Average Daily Nutrient Intake Levels, Measured as Percentages of the 1980 Recommended Dietary Allowances (RDAs), at Four Household Income Levelsa Intake as a Percentage of 1980 RDAs9 by Household Incomeb $16,000 and Over Under $6,000 to $10,000 to Nutrients $6,000 $9,999 $15,999 Food energy 80 84 86 86 Protein 154 163 167 }71 Calcium 80 83 89 87 Iron 99 102 105 104 Magnesium 77 19 85 85 Phosphorus 128 132 139 139 Vitamin A 119 115 114 117 Thiamin 115 108 116 11 ~ Riboflavin 125 125 137 130 Niacin 117 122 128 129 Vitamin B6 70 74 78 79 Vitamin B,2 120 132 144 145 Vitamin C 144 140 147 164 aFrom USDA, 1980. bIncome data from 1977-1978. differences with increased income are small and have not been tested for statistical significance; standard deviations were not provided in the NFCS publications. For eight of the nutrients, consumption exceeds the RDAs at all four income levels. By contrast, intakes of calcium, magnesium, and vitamin B6 are below their RDAs at all four income levels. In general, there is not a strong relationship between nutrient intake and income level. Some groups of the U.S. population have marked dietary deficiencies- for example, inadequate iron and calcium levels for many women and girls but these problems are not related to income (USDA, 19801. The United States is sufficiently wealthy so that income level is usually no longer a primary determinant of nutrient intake. However, for those who live in extreme poverty for example, migrant workers, Indian reservation inhabitants, and homeless city dwellers severely substandard diets are prevalent (Halcrow, 19771. The evidence on caloric consumption in Table 1 deserves special com- ment. The highest level of food energy intake is only 86% of the RDA. This finding does not agree with the generally accepted observation that overconsumption of calories is far more widespread than underconsump- tion in the United States. A recent food survey indicated that almost two- thirds of those surveyed had tried to lose weight in the past year (Leonard, 19821. Calories are unique among the nutrients, in that persons receive
48 WHAT FACTORS SHAPE EATING PATTERNS? direct and obvious feedback on their own individual caloric needs through weight gain or loss. Income and Food Consumption Patterns Although there are few substantial differences in nutrient intake by income level, the same nutrients can be obtained from different foods. and eating patterns might be markedly different across income groups. Table 2 presents the dietary intake of major food groups for the same four income levels as in Table 1 . Consumption of beef, cream and milk desserts, cheese, fats and oils, fruits, soft drinks, and alcoholic beverages increased more than 25% between the lowest and highest income groups. However, TABLE 2 Per Capita Average Daily Dietary Intake of Major Food Groups in Households at Four Income Levelsa Average Daily Intake (g) by Household income Levelb Under $6,000 to $10,000 to $16,000 $6,000 $9,999 $15,999 and Over Food Group (N = 4,026) (N = 4,249) (N = 7,286) (N = 11,624) Beef 40 46 51 57 Pork 19 20 19 20 Poultry 27 25 24 23 Other meats, fishC 96 107 109 112 Milk 254 279 295 291 Cheese 10 13 14 17 Cream and milk desserts 18 19 23 26 Eggs 29 30 24 24 Baked goods 103 112 112 112 Cereals, pastas 70 58 47 42 Fats 10 12 14 15 Vegetables 192 198 196 197 F=its 122 132 133 158 Legumes, nuts 30 30 26 21 Sugar, sweets 20 23 23 25 Soft drinks 139 166 176 174 Alcoholic beverages 32 33 45 62 Other beverages 360 387 412 436 aFrom USDA, 1983c. bTotal annual before-tax money earnings of all members of the household in which the surveyed person resided. Income data from 1977-1978. CIncludes lamb, veal, game, organ meats, organ meat mixtures, frankfurters, sausages, luncheon meat, fish, shellfish, and mixtures of mainly meat, poultry, and fish. Mixtures account for highest consumption in this food group. Includes coffee, tea, fmit drinks, and fruit-aces.
ECONOMICS AND NUTRITION 49 Me consumption of poultry, eggs, cereals and pasta, and legumes and nuts tended to decline wide increased income. Income Elasticity. Economists use "income elasticity" (the percent- age change in consumption corresponding to a percentage change in in- come) as a single statistic Nat reflects the relationship between income and consumption. Table 3 provides income elasticities estimated from the household portion of the 1977-1978 NFCS data (USDA, 1981a). Con- sumers consider most food groups to be necessities. Economists define a necessity as a good with an income elasticity greater than zero but less Wan one, so that as income increases consumption also nses, but less rapidly than the increase in income. As shown in Table 3, a few cate- gories - processed milk, cereal products, pork, eggs, and canned fruits and vegetablesare inferior goods with negative elasticities, in which case consumption declines as income increases and vice versa. The highest income elasticities are for alcoholic beverages and food away from home. TABLE 3 Income Elasticities Estimated from the Household Portion of the 1977-1978 Nationwide Food Consumption Surveya Food Group Income Elasticityb Total food Food away from home Food at home Dairy products Fresh milk Processed milk Cheese Fats and oils Cereal products Bakery products Beef Pork Poultry Fish, shellfish Eggs Sugar and sweets Fresh vegetables Fresh fruits Canned fmits and vegetables Frozen fruits and vegetables Soft drinks Alcoholic beverages 0.32 0.81 0.15 0.15 0.05 0.08 0.32 0.07 -0.12 0.15 0.23 0.01 0.07 0.33 -0.06 0.05 0.18 0.24 -0.04 0.44 0.19 0.90 aFrom USDA, 1981a. bIncome elasticity = percentage change in consumption corresponding to a loo change in income.
50 WHAT FACTORS SHAPE EATING PATTERNS? Food Consumed Away from Home. The average household purchased and consumed 23% of its total food, measured by dollar cost, away from home in 1977-1978 (USDA, 1983a, p. 131. However, this figure varied dramatically depending on income level. For example, households with annual incomes less than $5,000 purchased and consumed only 12~o of Weir total money value of food away from home, whereas households with incomes of $25,000 and higher spent 31% of their total food dollars on food away from home. When weekly per person costs for food con- sumed away from home were measured, households with incomes less than $5,000 (13% of all households in He NFCS) spent only $1.93 per person, in contrast to households with incomes of $25,000 and higher (10~o of the total survey), which spent $~.94 per person more than four times as much as the former group (USDA, 1983a, p. 13~. The weekly dollar value of food consumed at home was $15.38 per person for the same low-income households and $19.66 per person for the high-income households, a difference of only 28%. Food Consumed at Home. For some food items consumed at home, there are marked differences in consumption with income level. For ex- ample, the NFCS data for 1977-1978 indicated that consumption of fresh skim milk, yogurt, and sirloin steaks increased sharply as income rose (USDA, 1983a). For each of these foods, the difference in consumption between the low and high income levels was threefold or greater (Table 41. In contrast, cornmeal, grits, and sweet potato consumption decreased by at least a factor of three between the lower and higher income levels. Income is highly correlated with other sociodemographic factors, such as age, education, and race, that are also determinants of food consumption patterns. The patterns observed in Tables 1, 2, and 4 should not be attributed solely, or even predominantly, to income. In Table 4, for ex- TABLE 4 Per Capita Weekly Consumption of Some Foods at Home at Two Income Levelsa Weekly Consumption (g) by Household Income Foods Under $5,000 $25,000 and Over Fresh skim milk 82.29 265.14 Yogurt 18.29 54.86 Sirloin steak 22.86 86.86 Cornmeal 86.86 9.14 Grits 27.43 4.57 Sweet potatoes 41.14 13.71 aFrom USDA, 1983a.
ECONOMICS AND NUTRITION 51 ample, it can be seen that cornmeal, grits, and sweet potato consumption is high among rural Southern blacks, a group that contains a dispropor- tionately large portion of the country's poor. Multivariate analysis tech- niques, such as regression analysis, are necessary to isolate the effect of specific socioeconomic factors on food consumption. PRICES AND DIET Food prices, particularly price differences between substitute products, also strongly influence food consumption patterns. Some of the most marked changes in eating patterns during the last 20 years have occurred in meat and poultry consumption. Table 5 presents annual per capita consumption and price data for beef and veal, pork, and poultry. These data were estimated utilizing a food balance sheet or disappearance ap- proach, based on the flow of food items through the food distribution system. Considerable discrepancies may exist between consumption as measured by the balance sheet, household survey, and individual dietary intake methods. The prices in the table are given as consumer price indexes for each product, and 1960 rawer than 1967 is equal to a base of 100. The shifts in consumption of beef and veal, pork, and poultry appear to strongly reflect the relative price changes in the three categories. Be- tween 1960 and 1970 pork prices increased the most and poultry prices increased the least; in Me same period, pork consumption barely changed, whereas poultry consumption rose by 44%. Beef price increases were modest and, corresponding to beef's higher income elasticity (Table 3), beef consumption rose 25% between 1960 and 1970 as real income in- creased. During the 1970s, pork, with its lower price increases, became a more attractive buy than beef, and poultry became a markedly more attractive TABLE 5 Meat and Poultry: Annual Per Capita Consumption and Prices, 1960-1982a - Annual Consumption (kg)b Foods 1960 1970 1980 1982 Consumer Price Indexes (1960= 100)C 1960 1970 198() 100 100 100 1982 Beef and veal Pork Poultry aFrom USDA, 1981b, and USDA, 1983b. bRetail weight. CFor ease of comparison, consumer price index figures were recalculated from a 1967 = 100 base to a 1960 = 100 base. 32 27 16 39 28 22 36 31 28 36 27 29 130 141 l 101 293 255 178 300 315 182
52 WHAT FACTORS SHAPE EATING PATTERNS? buy than red meats, especially beef. Partially in reaction to these price changes, beef consumption between 1970 and 1980 declined 9%, pork increased 10%, and poultry increased 25%. Between 1980 and 1982, the sharp price jump in pork induced a marked drop in consumption. Unquestionably, other factors have affected these consumption shifts. However, a recent USDA study argued that "an overwhelming part of the variation in U.S. meat demand can be explained by changes in retail prices and consumer incomes" (Haidacher et al., 1982, p. iv). EFFICIENCY IN FOOD CONSUMPTION This section explores various perspectives on the efficiency of food consumption patterns in terms of the observed pattern of nutrients per dollar's worth of food, He USDA food plans, and least-cost diets. Dietary Efficiency Table 6 indicates the efficiency with which households at different income levels use their food budgets to obtain basic nutrients. The general pattern that emerges is Hat lower income households spend their food budgets more efficiently than higher income households by obtaining more nutrients per dollar's worth of food. The milligrams of thiamine per dollar of food, for example, declined from 0.89 to 0.72 mg between the lowest and highest income groups. The efficiency increase of lower income house- holds is probably even greater than suggested by Table 6, which only reflects food used at home. As discussed previously, higher income house- holds consume more of their meals away from home. And food consumed away from home, on the average, is substantially more expensive on a nutrient per dollar basis than food consumed at home. The USDA Food Plans The USDA (Cleveland and Peterkin, 1983) publishes four food plans thrifty, low-cost, moderate-cost, and liberal which provide nutritious diets at four cost levels. The food plans were developed using data on the observed food consumption patterns at various income levels. Re- Gently revised plans were based on the 1977-1978 NECS (USDA, 1983a,c). The food plans are designed to satisfy dietary standards (ac- cording to the RDAs for the major nutrients) at a given cost with the fewest possible changes from observed consumption patterns (Cleve- land and Peterkin, 19831. Compared to actual consumption patterns, the food plans contain fewer
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54 WHAT FACTORS SHAPE EATING PATTERNS? soft drinks, sugar and sweets, fats and oils, cheese, eggs, and meat, but more grain products and dry beans, peas, and nuts. These changes tend to lower costs and improve the nutritional content of the diet. In addition, these dietary changes would bring food consumption patterns more in line with the Dietary Goals for the United States developed by the Senate Select Committee on Nutrition and Human Needs (U.S. Congress, 1977~. These dietary goals, subsequently referred to as dietary guidelines, ad- vocated an increase in complex carbohydrate consumption (primarily from grain products) and a reduction in the consumption of sugar, fat (partic- ularly saturated fat), cholesterol, and salt. Least-Cost Diets An approach different from Mat of the USDA food plans has been the construction of least-cost or very low cost diet plans using linear programming techniques (Foyers, 1981~. The objective function in the program is to min- im~ze Be cost of the diet, subject to the constraint of satisfying basic nu~i- tional requirements with He given food prices. The solution is not restricted to correspond with observed eating patterns. Additional constraints Hat are typically added impose upper and lower quantity limits on particular foods to ensure a more varied and palatable diet. A recently developed very low cost diet plan met the same nutrient standards as the thrifty food plan at only 60% of its cost (Foytik, 19811. Adoption of such a diet, however, would require a substantial change in food consumption for even low-income households. For example, the diet allows powdered milk as the only dairy product and excludes meat other than chicken, hamburger, and beef chuck. The USDA food plans (Cleveland and Peterkin, 1983) recognize that cultural, psychological, and social factors affect food choices and that food consumption patterns are deeply ingrained and difficult to change. The typical household is limited in its ability and desire to pursue a more efficient diet. Significantly, the U.S. Food Stamp Program allotments are based on the USDA thrifty food plan; no one has seriously proposed that a least-cost diet be the basis for the program allotments. IMPORTANT CONCEPI UAL PERSPECTIVES A brief overview of two conceptual perspectives, the new household economics and food and nutrition profiles, provides further insight into American eating patterns.
ECONOMICS AND NUTRITION The New Household Economics 55 Gary Becker's model of time allocation, one of the more important additions to economic theory in the past 25 years, has given rise to the new household economics (Becker, 1965; Michael and Becker, 19731. This model has important implications for understanding eating patterns. The household is viewed as a production, as well as a consumption, entity that combines market-pt~rchased goods and household time to produce Me actual consumables. In the model, time is as crucial a constraint on con- sumption behavior as is the budget. When time is scarce, it becomes more valuable, and a shift toward a less time-intensive consumption pattern occurs. The purchase and preparation of food for consumption at home requires a substantial input of household time. One can view food choices as reflecting a fairly continuous range of required household production times. At the most time-intensive extreme, for example, are homegrown prod- ucts, followed by meals prepared from scratch- such as baking bread at home and then home cooking, which entails the use of some prepared foods, such as store-bought bread and canned or frozen vegetables. At the time-saving end of the range are convenience foods, such as prepared frozen dinners, followed by the least time-intensive extreme food con- sumed away from home. Prochaska and Schrimper (1973) found that as the value of a woman's time rose, as measured by her wage rate or potential wage, the household purchased more meals away from home. One of the major Rends today is the increased participation of women, particularly married women, in the work force. The resulting increased scarcity of household time partially explains the steadily increasing proportion of food eaten away from home and the current high demand for such products as microwave ovens and frozen dinner entrees. Food and Nutrition Profiles Some recent research by the Community Nutrition Institute (Leonard, 1982) indicated that American households follow particular, distinctive eating patterns. Households were divided into five food and nutrition profiles based on their dietary practices. '`Meat eaters" (30% of surveyed households) were heavy consumers of meat, sugar, and sweets. "People on the go" (14C%o of the sample) ate more meals away from home and spent more for food than other groups. "In a dither" households (16% of the sample) had a high convenience-food consumption. The "consci- entious" (15% of the sample) spent less for food, had more nutrition
56 WlIAT FACTORS SH~E EATING PA=E~S? knowledge, ate more at home, and cooked and baked more. "Healthy eaters" (25% of the sample) ate less meat, fat, sugar, and sweets, but ate more vegetables, fruits, and whole grains than did other households. The socioeconomic characteristics appear to be quite consistent for the households that fall into each of these food and nutrition profiles. For example, healthy eaters are typically from small households with older members. The conscientious include more high income families. In-a- dither households typically have many members, whereas on-the-go households have fewer members. CONCLUSIONS Historically, and in many societies of the world today, human food consumption consists of a simple diet usually dominated by a single staple, such as nce, wheat, or corn. Only the rich in such societies can afford more vowed diets. In sharp contrast, contemporary American eating pat- terns reflect the remarkably vmed diets that occur when economic abun- dance is widespread, although certainly not universal, in a society. Eating patterns in the United States demonstrate the complexity of human be- havior and continue to challenge researchers' understanding and expla- nation of them. Given the generally plentiful American food supply, public concern should focus particularly on the diets and nutritional needs of the poor, who do not share in this abundance. REFERENCES Becker, G 1965. A theory of the allocation of time. Econ. J. 74:493-517. Cleveland, L. E., and B. Peterkin. 1983. USDA 1983 family food plans. U.S. Department of Agriculture, Agricultural Research Service. Fam. Econ. Rev. 2:12-21. Foytik, J. 1981. Very low-cost nutritious diet plans designed by linear programming. J. Nutr. Educ. 13:63-65. Haidacher, R. C., 3. A. Craven, K. S. Huang, D. M. Smallwood, and J. R. Blayloc}~. 1982. Consumer Demand for Red Meats, Poultry, and Fish. Economic Research Service, National Economics Division. U.S. Department of Agriculture, Washington, D.C. Halcrow, H. G. 1977. Food Policy. McGraw-Hill, New York. Leonard, R. 1982. Nutrition profiles: Diet in the 80s. Community Nutritionist 1:12-17. Michael, R., and G. Becker. 1973. On the new theory of consumer behavior. Swed. J. Econ. 75:378-396. NRC (National Research Council). 1980. Recommended Dietary Allowances, 9th ed. A report of the Food and Nutrition. Board, Assembly of Life Sciences. National Academy of Sciences, Washington, D.C. Prochaska, F. J., and R. A. Sc}~imper. 1973. Opportunity cost of time and other socioeconomic effects on away-from-home food consumption. Am. J. Agnc. Econ. 55:595-603. U.S. Congress. 1977. Dietary Goals for the United States. Senate Select Committee on Nutrition and Human Needs, 95th Congress, 1st Session.
ECONOMICS AND NUTRITIOlV 57 USDA (U.S. Department of Agriculture). 1979. Money Value of Food Used by Households in the United States, Spring 1977. Science and Education Administration, Nationwide Food Consumption Survey 1977-78, Preliminary Report No. 1. U.S. Department of Agnculture, Hyattsville, Md. USDA (U.S. Department of Agriculture). 1980. Food and Nutrient Intake of Individuals in One Day in the United States, Spring 1977. Science and Education Administration, Nationwide Food Consumption Survey 1977-78. Preliminary Report No. 2. U.S. Department of Agri- culture, Hyattsville, Md. USDA (U.S. Department of Agnculture). 1981 a. Impact of Household Size and Income on Food Spending Patterns. Economics and Statistics Service, Technical Bulletin No. 1650. U.S. Department of Agriculture, Washington, O.C. USDA (U.S. Department of Agriculture). 1981b. Food Consumption, Prices, and Expenditures, 1960-1980. Economic Research Service, Statistical Bulletin No. 672. U.S. Department of Agriculture, Washington, D.C. USDA (U.S. Department of Agriculture). 1983a. Food Consumption: Households in the United States, Seasons and Year 1977-78. Human Nutrition Information Service, Consumer Nutrition Division, Nationwide Food Consumption Survey 1977-78, Report No. H-6. U.S. Department of Agriculture, Hyattsville, Md. USDA (U.S. Department of Agriculture). 1983b. Food Consumption, Prices, and Expenditures, 1962-1982. Economic Research Service, Statistical Bulletin No. 702. U.S. Department of Agriculture, Washington, D.C. USDA (U.S. Department of Agnculture). 1983c. Food Intalces: individuals in 48 States, Year 1977-78. Human Nutrition Infonnation Service, Consumer Nutrition Division, Nationwide Food Consumption Survey 1977-78, Report No. I-1. U.S. Department of Agriculture, Hyatts- ville, Md.
