The rise and spread of obesity in the United States is a serious concern for everyone, young and old alike. In 2009, 36 percent of U.S. adults and 17 percent of children were obese. Obesity, which is defined as excess body fat, has become a major problem over the past 30 years as it is associated with increased rates of cardiovascular disease, diabetes and cancer.
Dr. Lewis H. Kuller
Dr. Lewis H. Kuller gave the 2012 Robert S. Gordon, Jr. Lecture Feb. 15 on “The Obesity Epidemic: Why Have We Failed?” He is distinguished university professor of public health at the University of Pittsburgh.
Kuller shared the dire fact that “there is no evidence that we have slowed the obesity epidemic.”
Rather, data from the Centers for Disease Control and Prevention show the opposite: obesity is becoming endemic (that is, persistent) in the United States.
Lifestyle changes have contributed to the rise of the obesity epidemic. Several decades ago, many families transitioned to both parents working outside of the home, leading to a lack of time to prepare meals. This time shortage was followed by more food (such as fast food and snacks) being bought outside the home. Money spent on food prepared outside of the home was only 26 percent of a family’s food budget in 1970—that number increased to 48 percent by 2006.
Kuller described the way food not only has become a replacement for adverse behaviors—particularly for cigarette smoking and alcohol consumption—but also a way of life for many Americans: “Food is our number one social outlet,” he said. “Now we say, ‘Let’s meet for lunch’ or ‘Come to a dinner party.’ This is a new phenomenon of the past 20 or 30 years.
“We are the victims of the successes of previous generations,” said Kuller in describing the population’s decrease in physical activity over the last several generations due to technological advances. At the same time, the U.S. Department of Agriculture reports that the daily consumption of calories increased by about 12 percent from 1985 to 2000. It is these two factors together—increased energy intake (food consumption) and decreased energy expenditure (physical activity) that are the source of the obesity epidemic.
“Obesity has now become a socioeconomic disorder,” said Kuller. As happened with the epidemic of cigarette smoking, the fact that obesity can be bad for your health was first recognized among the better educated and wealthier groups of society. Today, lower socioeconomic classes have higher rates of obesity. In women, for example, there is a marked difference between obesity levels for those with a 4-year college degree (24 percent) versus those with less than a high school education (41 percent).
Kuller accepts his Gordon Lecture plaque in the company of NIH director Dr. Francis Collins (l) and Dr. Paul Coates, director of the Office of Dietary Supplements and acting associate director of the Office of Disease Prevention.
Photos: Ernie Branson
What can we do to address the obesity epidemic? Kuller recommends research into why many individuals are unable to maintain significant weight loss and what the long-term risks and benefits of bariatric surgery, such as gastric bypass, might be in the treatment of obesity.
Genetics could also play a role in why some people maintain low body weight and good health, despite the obesity epidemic. Obesity tends to occur frequently within families; genetic studies have already identified some genes related to obesity.
“Changes in family structure and work patterns are not unique to the U.S. and therefore cannot be the sole explanation of the obesity epidemic,” said Kuller, who recommended that researchers look into the dietary factors behind obesity. Japan and France have experienced the same social changes as the U.S., and have about the same levels of physical activity, but have lower rates of obesity. Possible explanations could be high levels of omega-3 fatty acids and low levels of beef consumption in the Japanese diet and a low level of snacking in the French diet.
Preventing weight gain in children should also be a high priority, said Kuller. Measures for preventing weight gain might include keeping snacking to a minimum, encouraging kids to choose water over sugary drinks and reducing meat consumption.
Kuller emphasized that any public health program to fight obesity should be based on research and well-documented clinical trials and effectiveness studies. “We should depend on good scientific investigation translated into effective clinical and public health programs,” he said.
The Gordon Lecture was established in 1995 in honor of Gordon’s outstanding contributions to the field of epidemiology and for his distinguished service to NIH, including organizing and serving as a member of several prominent working groups on AIDS research.