(April 2010) Obesity rates have increased dramatically across socioeconomic and racial/ethnic groups in the United States. The overall rate rose by 37 percent between 1998 and 2006—putting families' health at risk and raising health care costs. In contrast to developing countries, where people in higher socioeconomic groups are more likely to be obese than those living in extreme poverty (although this is changing), there is a strong correlation between lower income levels and higher obesity rates in the United States, especially for women. Much of this connection has to do with the food choices available to those with lower incomes.

Costs to Individuals and Society

Obesity is one of the biggest public health concerns in the United States, with widespread ramifications for the well-being of individuals, families, and communities, and health care costs to society. According to the Centers for Disease Control and Prevention, obesity prevalence has more than doubled over the past 30 years. One in three adults in the United States is obese. Obesity is measured using weight and height to calculate the Body Mass Index (BMI), which measures the amount of body fat one has. Obesity is defined as having a BMI of 30 or higher.

The effect of rising obesity is also felt across society and contributes to skyrocketing health care costs. Recent estimates put direct medical costs of obesity at $147 billion—almost 10 percent of total medical costs in the United States. The burden of diseases such as Type 2 diabetes that are associated with obesity falls disproportionately on those with lower incomes. Half of obesity-related medical costs are paid by Medicaid and Medicare, putting a strain on public budgets.1 But beyond the direct health costs of preventive, diagnostic, and treatment services are even greater indirect costs such as income lost from decreased productivity, missing work, and the value of future income lost by premature death.

Correlation Between Lower Income and Higher Obesity For Women

There is a strong correlation between lower incomes and high obesity rates for black and white women (see figure). However, obesity rates are relatively consistent across income for men and for Hispanics. Whereas 26.5 percent of men with annual household incomes of less than $10,000 are obese compared with 24.6 percent of men with incomes of more than $75,000, the gap for women is dramatic—35.6 percent of women in the lowest income group are obese compared with 15.5 percent in the highest income group.

Prevelance of Obesity by Annual Household Income for Persons Ages 18-64

prevalence of obesity

Source: Maximilian D. Schmeiser, Expanding Wallets and Waistlines (Madison, WI: Institute for Research on Poverty, 2008).

There is no clear explanation for the disparity by sex and income, but some speculate that lower-income men have physically demanding jobs and low-income women tend to be single mothers and have less time to focus on good nutrition/health than higher-income women. "The impact of socioeconomic status on body weight of women is a puzzle. In developing nations where being overweight is linked to higher socioeconomic status, not lower, it is still the women [who are most affected]. It is as though socioeconomic conditions had more of an impact on women's body weight and health than on men's," says Adam Drewnoski, director of the University of Wisconsin's Center for Obesity Research.

The link between low socioeconomic status and obesity has not been fully explained. The relationship is complex, with many other factors that must be examined. For example, heredity and educational attainment might affect both socioeconomic factors and obesity.2 Moreover, the link between socioeconomic status and obesity is important, but it is not the only issue relevant to rising obesity in the United States. Obesity rates are increasing fastest among black women at middle incomes and for black men at highest incomes.3 However, one factor is clearly linked to the correlation between low income levels and obesity—the availability of cheap, high-calorie processed food.

Cheap Food, Unhealthy Food

What drives high obesity rates among those with lower incomes? Much research has focused on the dietary choices and food availability among those with lower incomes. The cheapest foods contain high levels of refined grains and added sugars and fat, and tend to include processed ingredients and high-fructose corn syrup, proven to cause obesity.4 In addition, sodas and sugar-sweetened drinks have become more common, adding calories to daily diets.

According to Max Schmeiser, Center for Financial Security at the University of Wisconsin-Madison, "There is a preponderance of cheap, processed, calorically dense, fatty food in the United States. Therefore, for those with minimal financial resources, these unhealthy types of food are a primary source of their daily calories resulting in a caloric imbalance that leads to obesity." Combined with their palatability, energy-dense foods with higher levels of sugar and fat can be an attractive choice for those with lower incomes. Diets high in foods with lower energy density but higher nutrients, on the other hand, are linked to those with higher income levels.

"While at first pass income may seem like an important determinant of obesity, individual behaviors, as well as the means with which to carry out healthy behaviors, primarily drive the relationship between income and weight," says Schmeiser. "I believe the issue of greater obesity among low-income families relative to higher-income families is primarily driven by differences in information on good nutritional behaviors, cooking knowledge, and availability or access to healthy food. Higher income families...tend to live in neighborhoods with good grocery stores, or have access to cars to go to good grocery stores." In other words, income levels are tied to differing dietary habits and behavior that can lead to obesity.

The types of food available and dietary choices gets to the issue of behavior, but that is only one factor to be balanced among many others, including biology; societal norms; urban, suburban, or rural residency; and culture.

What about the near future? How will increasing economic insecurity affect Americans and their waistlines? Will rising unemployment lead to more spending on cheap and unhealthy food? Although counterintuitive, some research has indicated that the recession may actually lower obesity rates because people tend to get more physical exercise and eat at home when they are unemployed or during hard economic times. As the economy strengthens, physical activity is reduced and diets become less healthy, thereby increasing obesity.5

Eric Zuehlke is an editor at the Population Reference Bureau.


  1. CDC, "Overweight and Obesity: Economic Consequences," accessed at www.cdc.gov/obesity/causes/economics.html, on March 30, 2010. 
  2. Albert J. Stunkard and Thorkild IA Sorensen, "Obesity and Socioeconomic Status: A Complex Relation," New England Journal of Medicine 329, no. 14 (1993): 1036-37.
  3. Virginia W. Chang and Diane S. Lauderdale, "Income Disparities in Body Mass Index and Obesity in the United States, 1971-2002," Archives of Internal Medicine 165, no. 18 (2005): 2122-78.
  4. News at Princeton, "A Sweet Problem: Princeton Researchers Find That High-Fructose Corn Syrup Prompts Considerably More Weight Gain," accessed at www.princeton.edu/main/news/archive/S26/91/22K07/, on March 31, 2010.
  5. Christopher J. Ruhm, "Are Recessions Good for Your Health?"The Quarterly Journal of Economics 115, no. 2 (2000): 617-50.