FIGURE 2-4 Data are from NHANES I (1971–1974), II (1976–1980), and III (during 1988–1991), conducted by NCHS. Overweight individuals are those at or above the 85th percentile for persons 20–29 years, age and gender specific, in NHANES II.

to describe weight change patterns adequately. Williamson et al. (1990) analyzed data from a national sample in which subjects were weighed at two points 10 years apart. Among those 25–74 years old at the initiation of the study, the incidence of major weight gain (defined as an increase in BMI by 5 or more points) was highest in those 25–34 years old and then decreased with age. This pattern holds for both men and women, but the incidence of major weight gain was approximately twice as high among women within all age groups. The magnitude of gain decreased with increasing age until age 55, after which both men and women lost weight over the 10-year period. Among the nonover weight group, men and women 35–44 years old were most likely to become overweight, with the incidence of overweight decreasing with increasing age. Compared to white females, black women 35–44 years old gained more weight on average, were more likely to have experienced a major weight gain, and were more likely to become overweight (Williamson et al., 1990).