In the second episode of our two-part look at obesity, we challenge some of the basic tenets regarding obesity and weight gain. Last week, we focused on food — specifically processed food — and the role it plays in our nation's obesity crisis.
The prevailing theory regarding food and calories can be boiled down to a simple statement: If you take in more calories than you burn, you will gain weight. New York City Mayor (and national leader in the fight against obesity) Michael Bloomberg says it's simple thermodynamics. "If you want to lose weight, don't eat," he said. "If you take in more than you use, you store it."
"Yet the scientists who study the biochemistry of fat and the epidemiologists who track weight trends are not nearly as unanimous as Bloomberg makes out," writes David Berreby in Aeon. "In fact, many researchers believe that personal gluttony and laziness cannot be the entire explanation for humanity's global weight gain. Which means, of course, that they think at least some of the official focus on personal conduct is a waste of time and money."
What's the truth? New research is leading some to challenge almost universal assumptions.
LEARN MORE ABOUT OBESITY:
• The big fat truth
Being overweight increases a person's risk of diabetes, heart disease, cancer and many other chronic illnesses. But these studies suggest that for some people — particularly those who are middle-aged or older, or already sick — a bit of extra weight is not particularly harmful, and may even be helpful. (Nature)
• Obesity and exercise rates are both up: It's a matter of math
According to data just published in the online journal Population Health Metrics, during the last 10 years Americans have gotten more active in two-thirds of the nation's counties. They have also gotten fatter. To take California as an example, the percentage of women in the state who get sufficient weekly exercise rose over the decade from 50.7% to 59.2%. For California men, the positive change was from 59.4% to 61.3%. Yet, at the same time, obesity rates rose in every California county. (David Horsey, Los Angeles Times)
What's the Main Cause of Obesity -- Our Genes or the Environment?
Timothy Frayling, Professor of Human Genetics at the University of Exeter, thinks that genetic factors are the main driver for obesity in today's environment. Twin and adoption studies show consistently that variation in body mass index has a strong genetic component, with estimated effects of up to 70%, he says. Studies also show that people carrying two copies of a gene associated with obesity (the FTO gene) are, on average, heavier than those carrying two copies of the protective version. (Science Daily)