Recalled body weight and self-reported current weight were validated in a longitudinal study population by comparing recalls at 50 y to actual measures taken at ages 18, 30, 40, and 50 y. Recalled body weights were also compared with reported desired weights at these same ages. Self-reported weights at 50 y were equally accurate for both males and females; the mean reporting underestimate was -1.98 kg for males and -1.86 kg for females. Males' self reports at age 50 y were influenced by years of education (P less than 0.005) and current body size (P less than 0.0001) whereas females' were not. Correlations between recall of past weights and measured weights ranged from r = 0.87 at 18 y to 0.95 at 40 y. Recalls of past body weight were not significantly influenced by the passage of time, the number of years of education, or the accuracy of current weight reports. Current body size (wt/ht2) was significantly associated with life-time weight dissatisfaction in both sexes (P less than 0.0005).

The validity of long-term recall and current assessments of height, weight, and fatness relative to peers was investigated among 91 middle-aged participants in a longitudinal growth study. The recollections of 50-year-old participants concerning perceived body size in comparison to peers during childhood (aged 5-7 years), adolescence (aged 10-18 years), and at ages 30, and 40 years were compared with physical measurements taken at these times. Correlations between perceived and actual body size at all ages from childhood through middle-age were moderate but significant (P less than 0.005) and were influenced by gender and phases of physical growth (early and late adolescence). In general, accuracy of self-reports of current body size were not significantly better than recalls of body size up to 50 years earlier. Respondents' recall of various physiological events was also assessed. Females' actual and recalled year of menarche were correlated (r = 0.67; P less than 0.0001). Age at menarche was recalled within 1 year of the actual event by 84% of the females. Fifty percent of both sexes recalled their year of maximal growth in height within 1 year and recalled the timing of their maturation (early, average, or late) in relationship to their peers equally well (P less than 0.001).

The tracking of body mass index (BMI) over a 50-y period in a longitudinal study was examined by using both correlation coefficients and the Foulkes-Davis tracking index. Over the long term, BMIs before maturity were poor predictors of middle-aged BMI status in females but were good predictors in males. The correlation between females' BMI in childhood and their BMIs at two points during middle age (40 and 50 y) was zero; in males it was r = 0.36 and 0.41, respectively. Between-age correlations were high (P less than 0.0001) for both sexes, reflecting stability in BMI over the shorter term (less than or equal to 10 y). The tracking of BMI (with the Foulkes-Davis tracking index) from childhood to middle age was better for males than for females (P less than 0.1). Linear-regression analysis was also used to assess the predictability of relative body size in middle age from earlier measures; BMI in childhood accounted for 0% of the variance in females and 17% in males. We conclude that the prediction of ponderosity in middle age from BMIs early in life is more reliable for males than for females.