More Calories Cause of Obesity in America
Results of a new study shows that it is not inactivity, but more calories causing the obesity epidemic in the United States. The study, presented at the European Congress on Obesity shows that changes in physical activity in the United States has played a minor role in the current obesity epidemic.
Professor Boyd Swinburn, chair of population health and director of the World Health Organization Collaborating Centre for Obesity Prevention at Deakin University in Australia lead the research showing that Americans have become obese simply by eating more calories. The finding about the cause of obesity may become a breakthrough in providing treatment and help for obesity.
"There have been a lot of assumptions that both reduced physical activity and increased energy intake have been major drivers of the obesity epidemic. Until now, nobody has proposed how to quantify their relative contributions to the rise in obesity since the 1970s. This study demonstrates that the weight gain in the American population seems to be virtually all explained by eating more calories. It appears that changes in physical activity played a minimal role."
The researchers figured out how much Americans were eating. They looked at the food supply in the United States, including food produced, imported, exported, consumed, and used for animal feed, from the early 1970’s to early 2000, finding that Americans are simply consuming more calories and getting more obese.
The scientists tested calorie expenditure among 1,399 adults and 963 children. By measure the rate that calories are burned, the researchers were then able to establish how many calories are needed to maintain a stable weight. Next, they predicted how much weight Americans should gain over a thirty-year period, using data from a nationally representative survey (NHANES). They found that taking in more calories is entirely responsible for the rise in obesity seen in the United States.
Swinburn explains, "If the actual weight increase was the same as what we predicted, that meant that food intake was virtually entirely responsible. If it wasn't, that meant changes in physical activity also played a role. If the actual weight gain was higher than predicted, that would suggest that a decrease in physical activity played a role." They found that their predictions for weight gain exactly matched what was expected in children, leading to the conclusion that eating more calories is solely responsible for our obesity epidemic.
Swinburn says increasing physical activity for adults by 110 minutes a day would work to reverse our obesity epidemic – for children it would take 150 minutes of increased daily activity, but exercise alone might not do it. Americans will need to stop taking in more calories. Eliminating one hamburger a day for adults, and one soft drink and fries a day for children should get Americans back to average weights of the 1970’s.
European Association for the Study of Obesity