OBJECTIVE: To evaluate long-term patterns of weight change and progression to overweight and obesity during adulthood.

DESIGN: Prospective study. Changes in mean BMI, waist circumference (WC) and weight were assessed over a mean 26-year follow-up (1971-1975 to 1998-2001). Mean BMI (95 % CI) and mean WC (95 % CI) of men and women in BMI and age groups were computed. Mean weight change in BMI and age categories was compared using analysis of covariance.

SETTING: Framingham Heart Study Offspring/Spouse Nutrition Study.

SUBJECTS: Men and women (n= 2394) aged 20-63 years.

RESULTS: During follow-up, increases in BMI (men: 2.2 kg/m2; women: 3.7 kg/m2) and WC (men: 5.7 cm; women: 15.1 cm) were larger in women than men. BMI gains were greatest in younger adults (20-39 years) and smallest in obese older adults (50-69 years). The prevalence of obesity doubled in men (to 33.2 %) and tripled in women (to 26.6 %). Among normal-weight individuals, abdominal obesity developed in women only. The prevalence of abdominal obesity increased 1.8-fold in men (to 53.0 %) and 2.4-fold in women (to 71.2 %). Weight gain was greatest in the youngest adults (20-29 years), particularly women. Gains continued into the fifth decade among men and then declined in the sixth decade; in women gains continued into the sixth decade.

CONCLUSIONS: Patterns of weight change and progression to obesity during adulthood differ in men and women. Preventive intervention strategies for overweight and obesity need to consider age- and sex-specific patterns of changes in anthropometric measures.