Abstract
We employ a unique dataset of Major League Baseball (MLB) players - a select, healthy population - to examine trends in height, weight, and body mass in birth cohorts from 1869 to 1983. Over that 115-year time period, U.S. born MLB players have gained, on average, approximately 3 in. (7.6 cm) in height and 27.0 lb (12.2 kg) in weight, which has contributed a 1.6-unit increase in the body mass index. Where comparable data are available, U.S. born MLB players are about 2.0 in. (5.1cm) taller and 20.0 lb (9.1 kg) heavier but substantially less obese than males in the general U.S. population. But both groups exhibit similar height and weight trends; the majority of height and weight gains take place in cohorts that were born prior to World War II, followed by slower gains and occasional declines in height and weight for cohorts born in 1939 and later.