Key to understanding obesity

In 2013, the American Medical Association officially recognized obesity as a disease, five years after the Cleveland Clinics’ medical director for Employee Health defined it as such for all workers there. But in the past 13 years, there’s not been much of a shift in the understanding of what causes obesity — not in the general public, in people who contend with the condition or in the practice of medicine. Most people still think of obesity as a character flaw caused by consuming too many calories and not getting enough physical activity. But it’s much more complex than that.

A study analyzing National Health and Nutrition Examination Survey data found that even though U.S. adults’ BMI increased between 1988 and 2006, the amount of calories adults consumed and the energy they expended were unchanged. It also appears that the quality of calories consumed is as important a consideration as the total quantity. And genetics only explains about 2.7% variation in people’s weight, according to a study in Nature. That all adds up to this: The two most common explanations for obesity — calories in, calories out and family history — cannot, by themselves, explain the current epidemic.

So what are the other factors contributing to the obesity epidemic? Harvard’s T.H. Chan School of Public Health says “prenatal and early life influences; too much television watching; too little physical activity and sleep; and our food and physical activity environment are major influencers.”

That means if what your mom ate before you were conceived and while pregnant and if your first food experiences as an infant were unhealthy, your body became predisposed to obesity in childhood and as an adult.

Living in an environment that is hostile to outdoor physical activity contributes to obesity. And a toxic food environment where there’s a high-density of fast-food outlets and a lack of stores selling fresh foods fuels it too.

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. To live your healthiest, tune into “The Dr. Oz Show” or visit www.sharecare. com.