Is there a correlation between gas prices and obesity?

Obesity carries a risk of numerous disorders and diseases; some health economists think gas prices can influence rates of obesity.
Obesity carries a risk of numerous disorders and diseases; some health economists think gas prices can influence rates of obesity.
Jeff J. Mitchell/Getty Images

In 2005 to 2006, 33.3 percent of adult males and 35.3 percent of adult females in the United States­ were considered obese [source: CDC]. When you pool together everyone considered obese plus the overweight population, the tally rises to include nearly two out of three adult Americans [source: Philipson et al.].

Carrying extra weight, even as little as an extra 10 pounds (4.5 kilograms), isn't good for any of us. Being overweight or obese increases the risk for hypertension, coronary heart disease, high cholesterol, osteoarthritis, type 2 diabetes, stroke, gallbladder disease, sleep apnea and asthma, and has been linked to some cancers, including breast, endometrial and colon [source: CDC]. The U.S. Surgeon General reports obesity contributes to an estimated 300,000 deaths each year in the United States alone, compared with the roughly 400,000 deaths a year attributed to cigarette smoking [source: U.S. Department of Health and Human Services].

For years, doctors and health professionals have been schooling us on the benefits of a healthy diet and daily exercise, yet the number of obese people in the United States increases annually, blind to gender, age and race. Reasons for the obesity epidemic are complicated, but factors generally implicated include our behavior, genes, environment, culture and socioeconomic status.

­The economic costs of obesity are, themselves, corpulent. In 1995, costs associated with obesity reached $99 billion [source: Wolf and Colditz]. And according to the Surgeon General's "Call to Action to Prevent and Decrease Overweight and Obesity" report, costs in 2000 rose to more than $117 billion [source: CDC]. This includes not only the direct costs of preventative care, treatment and medications for obesity, but also the associated indirect costs of lost income, low productivity due to job absenteeism and premature death.

The science of economics can be applied to health care, and doing so can give us insights into why obesity rates are increasing. Health economists study ­how we can get the biggest bang for our buck by looking at clinical effectiveness and the cost-effectiveness of the health care industry; they also evaluate how equitably health benefits are distributed among the population.

In 2007, economist Charles Courtemanche analyzed the average U.S. state fuel prices and U.S. government-reported health trends of the last 20 years and determined that as gas prices increase, so does the amount of exercise we get, while rates of dining out drop. Is there a correlation between gas prices and obesity? According to Courtemanche's thesis, yes.

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­Let's look more closely at Courtemanche's findings and see how gas prices, weight and eating habits are linked.

Economic Trends and Weight

Research suggests that people might be more likely to eat at home when gas is expensive.
Research suggests that people might be more likely to eat at home when gas is expensive.
Buccina Studios/Photodisc/Getty Images

According to Charles Courtemanche in his doctoral dissertation in health economics, "A Silver Lining? The Connection between Gasoline Prices and Obesity," a causal relationship between rising gas prices and the reduction in body weight is theoretically possible. Based on his analysis, he proposes that for every $1 increase in gas prices, obesity rates will decrease correspondingly by as much as 9 percent after seven years, while saving 11,000 lives and $11 billion annually [source: Courtemanche].

The relationship between gas prices and weight is complex but basically twofold: When fuel prices soar, transportation costs increase and family budgets tighten.

When gas prices increase, people naturally look for ways to keep their dollars out of their gas tanks. In lieu of driving, they may change their routine. For example, they may choose to leave a gas-guzzling car parked at home in favor of walking, biking or taking public transportation to their destination. This adds more physical activity to their day -- good for weight loss because exercise eats up calories.

Secondly, Courtemanche suggests that because of the increased financial burden of higher gas prices, people may also change their dining habits.

Obesity rates rose 8 percent between 1979 and 2004 [source: Courtemanche]. Fuel prices declined, and during the Reagan administration, farmers with the biggest crop yields received the biggest government subsidies -- many farmers increased production to get in on that funding. Greater food production led to cheaper and bigger portions, notably in the fast-food industry, which in turn led to a calorie explosion: During the 1980s, available calories per capita rose to a whopping 3,900 a day [source: Doyle].

An increase in transportation costs doesn't just mean pain at the pump; the pain is also felt at the grocery store. When farmers and producers spend more to transport food from farms and warehouses to local stores, that cost is passed along to the consumer.

Less disposable income due to higher gas prices means less money to spend on food, whether dining in or out. Let's go back to that $1 rise in gas prices in a year. By Courtemanche's calculation, such an increase would reduce the number of meals eaten out by 6.5 meals. When a person eats 6.5 fewer restaurant meals a year, he or she saves 6,825 calories over a three-year period -- 6,825 calories is equivalent to just under 2 pounds (0.9 kilograms), 2 pounds of weight not gained [source: Courtemanche]. Home-cooked meals are generally less expensive -- and generally healthier -- than eating out, and tight household budgets can lead to a reduction in the slice allocated for food.

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­Courtemanche's research is a starting point for policy makers but not everyone agrees with the link between increasing gas prices and weight trends. Dan Sperling, head of the Institute of Transportation Studies at the University of California, Davis, believes people don't change their diet and exercise behaviors in the face of rising fuel costs, but rather defer to the easier, and lazier, solution: buying a fuel-efficient car [source: Scott]. Ultimately, it's an individual's choice where to put a stretched dollar -- in the tank or in the bank.

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Sources

  • Courtemanche, Charles. "A Silver Lining? The Connection between Gasoline Prices and Obesity." University of North Carolina at Greensboro. 2007. http://papers.ssrn.com/sol3/Delivery.cfm/SSRN_ID1135370_code450981.pdf?abstractid=982466&mirid=1
  • Doyle, Leonard. "Rising petrol prices could force obese Americans to hit the street." The Independent. 2007. http://www.independent.co.uk/news/world/americas/rising-petrol-prices-could-force-obese-americans-to-hit-the-street-402197.html
  • Haycox, Alan and Euan Noble. "What is health economics?" What is… ? series. Hayward Medical Communications. http://www.whatisseries.co.uk
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