Poverty and obesity: the role of energy density and energy costs1,2
Adam Drewnowski and SE Specter
Many health disparities in the United States are linked to inequal-
ities in education and income. This review focuses on the relation
between obesity and diet quality, dietary energy density, and
energy costs. Evidence is provided to support the following points.
First, the highest rates of obesity occur among population groups
with the highest poverty rates and the least education. Second,
there is an inverse relation between energy density (MJ/kg) and
energy cost ($/MJ), such that energy-dense foods composed of
refined grains, added sugars, or fats may represent the lowest-cost
option to the consumer. Third, the high energy density and palat-
ability of sweets and fats are associated with higher energy intakes,
at least in clinical and laboratory studies. Fourth, poverty and food
insecurity are associated with lower food expenditures, low fruit
and vegetable consumption, and lower-quality diets. A reduction
in diet costs in linear programming models leads to high-fat,
energy-dense diets that are similar in composition to those con-
sumed by low-income groups. Such diets are more affordable than
are prudent diets based on lean meats, fish, fresh vegetables, and
fruit. The association between poverty and obesity may be medi-
ated, in part, by the low cost of energy-dense foods and may be
reinforced by the high palatability of sugar and fat. This economic
framework provides an explanation for the observed links between
socioeconomic variables and obesity when taste, dietary energy
density, and diet costs are used as intervening variables. More and
more Americans are becoming overweight and obese while con-
suming more added sugars and fats and spending a lower percent-
age of their disposable income on food.
Am J Clin Nutr 2004;
income, energy density, food costs, added sugar, added fat, palat-
ability, socioeconomic status
Poverty, food insecurity, obesity, education,
Rising rates of obesity in the United States have been linked
to food supply trends and to the growing consumption of
energy-dense foods (1–4). An increased consumption of snacks
(5), caloric beverages (6, 7), and fast foods (8) by children and
young adults has been shown repeatedly to be associated with
obesity and excess weight gain. Studies have examined the
contribution to the obesity epidemic of dietary sugars and fats
(6, 9), larger portion sizes (10), and the lower nutrient density
of foods eaten away from home (11). The content of school
lunches has been scrutinized (12), and even food-assistance
programs have come under attack for their alleged role in
“fattening the poor” (13, 14).
Public health policies for the prevention of obesity increas-
ingly call for taxes and levies on fats and sweets, both to
discourage their consumption and to help promote alternative
and healthier food choices (15, 16). Past studies on dietary
antecedents of obesity have addressed taste preferences for
sugar and fat as well as preferences for energy-dense foods
(17–19). In contrast, the relation between fat and sugar con-
sumption, dietary energy density (MJ/kg), and energy costs
($/MJ) has not been explored. Establishing associative links
between obesity, dietary energy density, and energy costs is the
chief focus of this report
POVERTY AND OBESITY
Obesity rates in the United States have risen sharply over the
past 2 decades (20–22). By 1999–2000, 64% of adults aged ?
20 y were classified as overweight and 30% were classified as
obese. Overweight is defined as a body mass index (BMI; in
kg/m2) ? 25, whereas obesity is defined as a BMI ? 30 (20). A
sharp increase in the number of massively obese people (BMI ?
35) has been observed in certain population subgroups (23).
There is no question that the rates of obesity and type 2
diabetes in the United States follow a socioeconomic gradient,
such that the burden of disease falls disproportionately on
people with limited resources, racial-ethnic minorities, and the
poor (20). Among women, higher obesity rates tend to be
associated with low incomes and low education levels (21,
23–25). The association of obesity with low socioeconomic
status (SES) has been less consistent among men (21, 25).
Minority populations (except for Asian Americans) have
higher rates of obesity and overweight than do US whites (21).
Analyses of data for 68 556 US adults in the National Health
Interview Survey by the Centers for Disease Control and Pre-
vention showed that the highest obesity rates were associated
with the lowest incomes and low educational levels (22). The
relation between obesity and education and income, based on
charts published by the Centers for Disease Control and Pre-
vention (22), is shown separately for men and women in
Figure 1. Although obesity rates have continued to increase
1From the Center for Public Health Nutrition, Departments of Epide-
miology and Medicine, University of Washington, Seattle (AD), and the
US Department of Agriculture Western Human Nutrition Research Center,
University of California, Davis (SES).
2Address reprint requests to A Drewnowski, Nutritional Sciences Pro-
gram, 305 Raitt Hall, Box 353410, University of Washington, Seattle, WA
98195–3410. E-mail: email@example.com.
Received March 18, 2003.
Accepted for publication June 9, 2003.
Am J Clin Nutr 2004;79:6–16. Printed in USA. © 2004 American Society for Clinical Nutrition
at Univ of Laval Bibliotheque Sec Des Acquisitions on May 21, 2008
steadily in both sexes, at all ages, in all races, and at all
educational levels (26), the highest rates occur among the most
Food insecurity and obesity also appear to be linked (27, 28).
The concept of food insecurity, originally adapted from work
by the Food and Agriculture Organization of the United Na-
tions, was used to examine access to food by low-income
households (29). Participants in the 1977–1978 Nationwide
Food Consumption Survey were asked which of the following
statements best described the food eaten in their household:
“enough and the kind wanted to eat,” “enough but not always
the kind wanted to eat,” “sometimes not enough to eat,” or
“often not enough to eat.” These questions distinguished be-
tween food insecurity and overt hunger (28).
In the 1995 US Department of Agriculture (USDA) Current
Population Survey, food insecurity was defined as “limited or
uncertain availability of nutritionally acceptable or safe foods”
(30, 31). The 1995 Current Population Survey judged 11.9% of
all US households to be food insecure (30). However, not all
food-insecure households showed evidence of hunger, and the
relation between poverty, food insecurity, and hunger was a
complex one (32, 33). There was no one-to-one correspon-
dence between income-based measures of poverty and food
insecurity, and only 13.1% of those in poverty were affected by
hunger (34). Of the food-insecure households, 65% (7.8% of
total) showed no evidence of hunger, 28% (3.3%) reported
moderate hunger, and 6.9% (0.8%) reported severe hunger
(30). There was also a positive association between food inse-
curity and participation in the Food Stamp Program (27),
because food-insecure persons were more likely to seek food
In the third National Health and Nutrition Examination Sur-
vey (NHANES III), 1988–1994, food insufficiency was de-
fined as “sometimes” or “often” not having enough to eat (27).
The prevalence of food insufficiency was 4% in the total
sample but as high as 14% among low-income respondents.
According to the USDA Economic Research Service, 10.1%
(10.5 million) of American households reported some level of
food insecurity in 1999, including 9.5% of adults and 16.9% of
children aged ? 18 y. Households with children were twice as
likely to report food insecurity (35). Among low-income fam-
ilies, food insufficiency was associated with single-parent fam-
ilies, not having health insurance, and having a family head
with ? 12 y of education.
Among women, food insecurity without hunger appears to be
associated with overweight. Analyses of NHANES III data (28)
showed that women, but not men, in food-insufficient households
were more likely to be overweight than were food-sufficient
women (58% compared with 47%). In another study, food-inse-
cure women were ? 10 lb (4540 g) heavier on average than was
and lower diet quality might be expected, the association between
food insecurity and overweight was something of a paradox (28).
Given that low-income families are the chief beneficiaries of
food-assistance programs, exploration of the causal connections
between food insecurity and obesity has major implications for
food and nutrition policies in the United States (28).
ENERGY-DENSITY COST FRAMEWORK
In 1992, Basiotis (37) hypothesized and confirmed a behav-
ioral model in which household members faced with diminish-
ing incomes first consumed less expensive foods to maintain
energy intakes at a lower cost. To multiple-choice questions
about food sufficiency, these participants responded “enough
but not the kinds of food we want to eat,” which implied
adequate energy intakes but a limited range of food choices.
Only when incomes diminished still further did households
reduce dietary energy to intakes below daily requirements,
which resulted in overt deprivation. The food-insufficiency
FIGURE 1. Obesity as a function of income and education. Adapted from reference 22.
POVERTY, OBESITY, AND DIET COSTS
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DREWNOWSKI AND SPECTER
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