A longitudinal study of nutritional intake in men.

Seven-day dietary diaries were provided by 180 male participants in the Baltimore Longitudinal Study of Aging during each of three time periods (1961 to 1965, 1966 to 1970, and 1971 to 1975). These men are a highly educated, upper-middle class group. At the time of their first diary, they were aged 35 to 74 years. The data were analyzed for aging, cohort, and time effects on diet by utilizing three types of research designs concurrently: cross-sectional, longitudinal, and time series. The nutrients considered were calories, protein, carbohydrate, fat, saturated fatty acids, polyunsaturated fatty acids, and cholesterol. Aging had a negative effect on intake of calories, fat, saturated fatty acids, and cholesterol. Cohort effects were not observed for any of these nutrients. Over time, intake of carbohydrates and cholesterol declined, while intake of polyunsaturated fatty acids rose.