Federal Obesity Guidelines
More than Half of All Americans are Too Fat
Source: National Heart, Lung and Blood Institute
Overweight and obesity continue to be an alarming public health problem in the United States, affecting 97 million American adults— an astonishing 55% of the population. Between 1960 to 1994, the prevalence of obesity in adults increased from nearly 13% to 22.5% of the U.S. population, with most of the increase occurring in the 1990s. These findings are recorded in the first federal guidelines on the identification, evaluation, and treatment of overweight and obesity in adults, which was released by the National Heart, Lung, and Blood Institute (NHLBI) in June 1998.
“There are several possible reasons for the increase,” asserted Karen Donato, coordinator of the Obesity Education Initiative. “When people read labels, they're more likely to notice what's 'low fat and healthy' but may not be looking at calories. Also, more people are eating out and portion sizes have increased. Another issue is decreased physical activity. So people are consuming more calories and are less active. It doesn't take much to tip the energy balance,” she said.
According to the guidelines, assessment of overweight involves evaluation of three key measures — body mass index (BMI), waist circumference, and a patient's risk factors for diseases and conditions associated with obesity. Overweight is defined as having a BMI of 25 to 29.9 and obesity as a BMI of 30 and above, which is consistent with the definitions used in many other countries. BMI describes body weight relative to height and is strongly correlated with total body fat content in adults. According to the guidelines, a BMI of 30 is about 30 pounds overweight and is equivalent to 221 pounds in a 6' person and to 186 pounds in someone who is 5'6. The BMI numbers apply to both men and women. Some very muscular people may have a high BMI without health risks.
Waist circumference, which is strongly associated with abdominal fat, is another measure of overweight— excess abdominal fat is an independent predictor of disease risk. A waist circumference of over 40 inches in men and over 35 inches in women signifies increased risk in those who have a BMI of 25 to 34.9.
According to the guidelines, the most successful strategies for weight loss include calorie reduction, increased physical activity, and behavior therapy designed to improve eating and physical activity habits. Other recommendations include:
- Engaging in moderate physical activity, progressing to 30 minutes or more on most or preferably all days of the week.
- Reducing dietary fat alone—without reducing calories—will not produce weight loss. Cutting back on dietary fat can help reduce calories and is heart-healthy.
- The initial goal should be to reduce body weight by about 10 percent from baseline, an amount that reduces obesity-related risk factors. With success, and if warranted, further weight loss can be attempted.
- A reasonable time line for a 10 percent reduction in body weight is six months of treatment, with a weight loss of 1 to 2 pounds per week.
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The guidelines have been reviewed by 115 health experts at major medical and professional societies, and have been endorsed by 54 professional societies, government agencies, and consumer organizations. The published report, “Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults” has been distributed to primary care physicians in the U.S. as well as to other interested health care practitioners. It is available on the NHLBI Website.
Single free copies of the consumer tips referred to above are available by writing to the NHLBI Information Center, P.O. Box 30105, Bethesda, MD 20824-0105.
Measuring Body Mass
