Moccasins rejoice!
One study puts the blame for obesity to overeating, rather than inactivity.
Digital Vision
couch potato lifestyle today has been blamed for the skyrocketing rates of obesity, but the cause of this trend may have more to do with the potato as the sofa. An analysis of 20 years of published data on the daily energy expenditure of people indicates that overeating, rather than a sedentary existence, is the primary cause of the obesity epidemic in the industrialized world.
What is certain about obesity is that it is ultimately caused by an imbalance in the budgets of the energy of the people. When you take in more calories than you burn, your body squirrels the excess away as fat. The imbalance can result from too much food, too little physical activity, or a combination of both. Studies of exercise and self-reported eating habits have suggested that daily physical activity has decreased in recent decades, while the daily calorie intake remained stable. But the accounts of people of their own behavior is notoriously inaccurate.
To obtain more reliable data, Klaas Westerterp biologists from the University of Maastricht in the Netherlands and John Speakman of the University of Aberdeen in the UK turned to a technique called doubling method labeled water (DLW). Over 2 weeks, the subjects for minimal amounts of water molecules, hydrogen or oxygen atoms contain additional neutrons. The body takes on oxygen for metabolism, expelling some of them in the carbon dioxide. By tracking heavy ratio of hydrogen and oxygen in urine, scientists can estimate the overall rate of a person's metabolism.
The researchers analyzed data from a study of DLW Public Health 20 366 residents of Maastricht led Westerterp published. They compared these data with the results of published studies conducted in the United States and the developing world. DLW "is the gold standard," Speakman said, "so we gathered all available data."
The results indicate that people burn just as many calories as they ever did. The daily energy expenditure was similar in all studies throughout the period, if the subjects were in Europe, the US, or the developing world. over the same 20 year period, the prevalence of obesity doubled in the Netherlands and more than tripled in the United States. "We are not saying that exercise does not make a difference," says Speakman. "If you train for marathons, so of course you are in shape. But for people on average daily physical activity has not changed. In the time we spend watching TV today, people probably listened to the radio in the 1950s and read books in the 1920s, "he concludes. "This work suggests that the obesity epidemic has been largely driven by the increase in food intake."
"The study is provocative," says Loren Cordain, a physiologist at Colorado State University in Fort Collins. "But I wouldn 't hang my hat," he said, because the DLW studies used different experimental procedures, making them difficult to compare. Cordain also concerned that the 366 people studied in Maastricht might not be representative of the entire country. Speakman replied that "we know of no reason why they would not be representative."
Related site
- Calculate your own energy expenditure
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