The health risks of obesity are well-established— type 2 diabetes , high blood pressure , stroke , and cancer of the breast , colon , and kidney , among other conditions. And perhaps most startling to the 32% of American adults who are obese, is a greater risk of death. Obesity is defined as a body mass index (BMI) of 30 or greater (BMI is a measure of body fatness based on your height and weight).

It is unclear, though, if the additional 34% of Americans who are overweight (BMI of 25.0-29.9), but not obese, also have a higher risk of dying prematurely. After monitoring more than half a million Americans for ten years, researchers from the National Institutes of Health (NIH) reported, in the August 24, 2006 New England Journal of Medicine , that both overweight and obesity are associated with an elevated risk of premature death among nonsmoking, healthy adults.

About the Study

NIH researchers analyzed data from health questionnaires from 527,265 people in the NIH-AARP Diet and Health Study. When the study began in 1995-1996, volunteers were between 50-71 years old. Each volunteer reported their height and weight; researchers used these measures to calculate BMI and then divided the participants into the following groups:

  • Underweight: BMI <18.5
  • Normal weight: BMI 18.5-24.9
  • Overweight: BMI 25.0-29.9
  • Obese: BMI ≥ 30.0

Researchers tracked participant deaths through January 2006 and compared the risk of death across the BMI groups.

During 10 years of follow-up, 42,173 men and 19,144 women died. After adjusting for certain factors like smoking status and preexisting disease, researchers found that both overweight and obesity were linked to an elevated risk of premature death among nonsmoking, healthy adults.

Based on the study, there is a 20-40% greater risk of death for a nonsmoking, healthy person who was overweight at age 50 compared to a normal weight person (Table 1). For someone who was obese at age 50, the risk of death jumps even more dramatically to double or triple that of a normal weight person. The researchers determined that excess weight among nonsmokers accounted for about 18% of premature deaths.

Table 1. Weight ranges for an adult who is 5 feet, 8 inches tall

Weight range Weight status, based on BMI
125-163 poundsNormal weight
164-196 poundsOverweight (BMI 25-29)
197 pounds or moreObese (BMI > 30)

Since the BMI calculations depended on heights and weights reported by volunteers rather than measured by researchers, the accuracy of these measures may be limited. And while the study sample was quite large, the participants were from only six states and two cities and thus may not be representative of all Americans. Furthermore, in both smoking and nonsmoking men, a statistically increased risk of death was technically seen only in those with a reported age of 50 and BMI above 26.4 (195 pounds for a six-foot tall person). The risk for nonsmoking women was statistically evident at a BMI of 25 (see table 1 above). However, even in men there was a trend to higher death rates with any weight above a BMI of 23.5 (173 pounds at six feet tall).

How Does This Affect You?

According to this study, carrying excess weight increases the risk of dying prematurely. And this risk continues to rise with the number on the scale. This is not just an American problem. Another report in the same issue of the New England Journal of Medicine looked at more than one million Koreans ages 30-95. As with the American study, the death rate was higher among overweight or obese Koreans than those of normal weight.

If your weight puts you in the overweight or obese category, it’s time for some lifestyle changes. The first step is to lose weight gradually. For many people, small daily changes—taking the stairs and drinking more water—are more doable than a complete lifestyle overhaul. Here are some ways you can lose weight:

  • Keep a regular eating schedule and don’t skip meals
  • Eat fruits and vegetables at each meal (but keep an eye on the calories they contain)
  • Use skim or 1% milk, rather than whole milk or cream, in your coffee or tea
  • Snack on a high-fiber, low-sugar breakfast cereal, rather than chips
  • Use smaller plates and bowls and don’t go back for seconds
  • Grill, steam, and bake rather than fry foods
  • Eat a vegetarian meal 2-3 times per week (but remember that not all vegetarian meals are either low-calorie or even healthy, so choose wisely)
  • Avoid soda and fruit drinks, choose water, diet drinks, and 100% fruit juice (1 cup juice/day at most)
  • Eat slowly; put your fork down between bites and swallow before picking it up again
  • Take a walk during your lunch break
  • Do sit-ups or use dumb bells while watching TV
  • Make exercise fun—choose activities you enjoy, recruit a friend, involve the family, join a group, or treat yourself to nice workout gear
  • Find ways other than eating to deal with stress or boredom, such as reading, doing yoga, or jumping rope

Also consider meeting with a registered dietitian who can personalize a weight control plan for you.