If you think America's obesity epidemic will pass you by because you are young and fit now, think again. In the past 30 years, the portion of the population that is obese has risen from 15 percent to 33 percent. Now the Centers for Disease Control and Prevention predicts that more than 42 percent of people will be obese by 2030 – not just overweight, but clinically obese, with a body mass index of more than 30. (A healthy BMI for men is around 19 or 20.) And scientists can only speculate about the percentage of people who will be overweight.
This new statistic, while frightening, isn't a surprise to obesity experts who have watched and forecasted America's growing levels of fatness for decades. And now experts are scrambling to understand why. Most blame the epidemic on a variety of factors that can include everything from more chemicals in personal-care products, furniture, and food to the lack of sidewalks on city streets and a proliferation of elevators in buildings. Among many leading authorities, a contentious debate exists over whether it's the calories or the carbs in food that cause people, including those who work out every day, to pack on the pounds. Here, we examine five different perspectives from some of the country's leading obesity experts.
Calories in versus calories out.
Dr. George Bray
Chief of clinical obesity and metabolism at Pennington Biomedical Research Center
Dr. George Bray graduated from Harvard Medical School in 1957 and has since spent nearly all his time studying obesity. Now, at 81, Bray is arguably the most influential, oft-published figure in the research world of obesity. Chief of obesity and metabolism at Louisiana's Pennington Biomedical Research Center, Bray is most noted for developing the "calories in-calories out" theory – that people gain weight when they eat more calories than they burn.
Bray believes there's no insidious reason behind the rise in obesity. Some people have control around food while others eat more than they should "because it tastes good," he says. Bray admits recent research has added nuance to his calories in-calories out theory: Calories in beverages like soft drinks and fruit juices pack a worse punch because they contain fructose, or fruit sugar, which the body converts more readily into fat than other sugars. Liquid calories also do more damage than solid food, because they pass through the stomach more quickly. Aside from these exceptions, "cumulative calories are unequivocally the thing that is causing obesity," he says. Which means you'd gain weight as easily eating too much pasta as you would eating steak.
Credit: Don Bayley / Getty Images
Bray believes government corn and sugar subsidies have driven up the availability of cheap, nutritionally void, high-caloric food and candy: "The government caused the problem. Don't they have to do something about it?" Bray says subsidies should be removed and food advertising aimed at kids limited.