By W. Scott Butsch, M.D., M.Sc., and Fatima Cody Stanford, M.D., M.P.H., M.P.A.
For more than a decade, obesity has been recognized as an epidemic condition in the United States, and the numbers certainly justify the characterization.
Statistics from the
U.S. Centers for Disease Control and Prevention show that more than 36 per cent of adults have obesity, and a report from the
Trust for America’s Health and the Robert Wood Johnson Foundation declares that not a single state in the union has an adult obesity rate of less than 20 percent. While the obesity rate for children is lower, it, too, is alarming: 17 percent of Americans aged 2-19 years – nearly 13 million children and adolescents – have obesity.
Despite enormous attention and numerous programs to reduce obesity – by federal, state, and local governments, community agencies, businesses, schools, and others – the high numbers persist, putting millions of Americans at risk of some of the leading causes of preventable death, such as heart disease, stroke, type 2 diabetes, and certain types of cancer.
The standard means of measuring obesity is the
Body Mass Index (BMI), a formula that estimates a person’s total body fat based on height and weight. Someone with a BMI of 25-30 is considered overweight; a BMI of 30 or more is classified as having obesity. While BMI is a useful tool to estimate health risk, examining obesity and its health risks on an individual basis is more complicated than just determining a single number.
When we’re born, our bodies contain a certain number of fat cells, which is important, because they store fat for energy. Fat cells accumulate in childhood, but when we become adults, our bodies don’t gain additional fat cells; these cells just increase or decrease in size.
That increase or decrease in the size of the fat cells is what leads to weight gain or loss. This is important to understand, because it is the amount of fat in a person’s body that relates to health risks and raises concern among physicians. That’s why prevention in childhood is so critical: if a person is overweight or has obesity as a child, it is likely that overweight and obesity – and the accompanying conditions of poor health - will follow as an adult.
Conventional wisdom has thought of obesity as primarily a lifestyle issue, even a character flaw, with people simply eating too much and not getting enough physical exercise. However, research over the last two decades describes a highly complex system that controls our body weight, with many other factors besides diet and exercise, in addition to our own biology, contributing to obesity.
Also within the past few decades, our environment has changed dramatically, and some of those changes have led to weight gain in individuals predisposed to obesity. A proliferation of fast-food restaurants, exposure to high calorie foods and the easy availability of processed foods, reduction in sleep, increased stress in a fast-paced world, and a tendency toward more sedentary lifestyles encouraged by technological advances all have played a role in weight gain.
Diet and exercise are important, but they’re only parts of the puzzle. Consideration of diet, for example, should reflect not just how much we eat, or how we limit portion size, but what we eat. Eating more healthful foods, with an eye on nutritional content, is a much better approach. That’s why it’s important to read and understand the nutrition labels on food. The new nutrition facts label, announced by the Food and Drug Administration in May, should be a step forward in helping consumers make better choices about the foods they purchase.
A similar misconception exists about exercise and its role in regulating weight. Research shows that physical activity does a good job of helping people maintain weight, but is less effective in losing weight.
Other factors can also lead to being overweight or having obesity, such as the quality and quantity of our sleep, and even certain medications, like anti-depressants and medications for high blood pressure, may contribute to weight gain.
For patients with overweight and obesity, it is important to recognize the associated adverse effects on health over a lifetime. It is equally important for those patients to engage in a critical self-assessment, preferably with a physician, on all of the factors that can be linked to weight gain, to see where improvements can be made to help reduce weight.
For more information on obesity and how it affects health, visit the Obesity Society at
www.obesity.org. For a video discussion on the misconceptions of obesity, visit
W. Scott Butsch, M.D., M.Sc. and Fatima Cody Stanford, M.D., M.P.H., M.P.A. are physicians at the Massachusetts General Hospital Weight Center and members of the Massachusetts Medical Society’s Committee on Nutrition and Physical Activity. Physician Focus is a public service of the Massachusetts Medical Society. Readers should use their own judgment when seeking medical care and consult with their physician for treatment. Send comments to PhysicianFocus@mms.org.