The average body mass index (BMI) in men between the ages of 20 and 74 has increased from 25.1 in the early 1960s to 27.9 between 1999 and 2002, the last year there was a National Health and Nutrition Examination Survey. Men 75 and over weren't sampled until 1988, but their BMI has also increased. The rising average BMI is significant because BMIs between 18.5 and 24.9 are normal, while people with BMIs 25 and above have overweight or obesity (30 and above).
The BMI began replacing weight-for-height tables as the most common way of predicting future obesity-related diseases after medical researchers concluded in the 1970s that there was a correlation between the BMI equation and death caused by heart attacks, hypertension, stroke and other coronary-related diseases, according to "Beyond BMI," a "Slate" magazine article published on July 20, 2009. The equation is weight (in kilograms) divided by height (in meters) squared. One kilogram (kg.) equals 2.2 pounds (lbs.), and one meter (m.) equals 39.4 inches (in.).
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The Centers for Disease Control and Prevention (CDC) estimated Americans' average BMI in 1960 to 1962, 1971 to 1974, 1976 to 1980, 1988 to 1994 and 1999 to 2002. Its "Mean Body Weight, Height, and Body Mass Index" report doesn't reveal how many people it examined, but says the results represent "the entire U.S. population." The average BMI of 20- to 74-year-old men was 25.1 in 1960 to 1962, 25.7 in 1971 to 1974, 25.6 in 1976 to 1980, 26.8 in 1988 to 1994 and 27.9 in 1999 to 2002. After men 75 years old and above were examined, men's average BMIs were 26.7 from 1988 to 1994 and 27.8 from 1999 to 2002.
BMIs By Age
Men's average BMI generally increases with age until they reach 60. Men 20 to 29 had the lowest BMIs in every survey, including 24.3 in 1960 to 1962 and 26.6 in 1999 to 2002. Men 50 to 59 had the highest BMIs in 1988 to 1994 (27.8) and 1999 to 2002 (28.7). The BMIs of all age groups increased from 1960 to 2002. Older age groups had larger increases. The BMIs of 60- to 74-year-olds increased 3.7 (24.9 to 28.6). Other increases were 3.1 for 50- to 59-year-olds (25.6 to 28.7), 2.8 for 40- to 49-year-olds (25.6 to 28.4) and 2.3 for 30- to 39-year-olds (25.2 to 27.5).
BMIs By Race
The CDC reported average BMIs by ethnicity and race in its 1988 to 1994 and 1999 to 2002 surveys. Mexican-American men had higher BMIs than non-Hispanic whites and non-Hispanic Blacks--27.3 in 1988 to 1994 and 28.0 in 1999 to 2002. White men had higher BMIs than black men--26.8 in 1988-1994 and 27.9 in 1999-2002. Black men had average BMIs of 26.6 in 1988 to 1994 and 27.5 in 1999 to 2002.
You should not panic if your BMI interpretation indicates you have overweight, and you should not relax if your BMI is normal, the CDC warns. The BMI is just one forecaster of future obesity-related disease. Others include high blood pressure, high total and bad cholesterol levels, lack of exercise and waist circumference.
- Centers for Disease Control and Prevention: About BMI for Adults
- Centers for Disease Control and Prevention: Mean Body Weight, Height, and Body Mass Index
- “Slate" magazine; Beyond BMI; Jeremy Singer-Vine; July, 20, 2009
- Centers for Disease Control and Prevention: Adult BMI Calculator: English
- Centers for Disease Control and Prevention: Healthy Weight: It's Not a Diet, It's a Lifestyle