The relationship between smoking and weight was examined in data of the Lipid Research Clinic (LRC) Prevalence Study in Richfield, Minnesota. Weight was analyzed according to smoking status, age, and sex, holding constant self-perceived physical activity relative to others of the same age and sex. Our findings confirm that weight differences between smokers of 15-29 cigarettes a day (cig/day) and those who never smoked are noticeable in 20-39 year olds and quite marked in the 40-59 year age group. Ex-smokers are somewhat heavier than those who never smoked while, among smokers, a U-shaped curve exists with those smoking 15-29 cig/day being the lightest class. Height varied little between smoking classes. Daily caloric intake was estimated based on 24-hour dietary recalls and analyzed according to smoking status, sex, and age. The results showed that smokers of 15-29 cig/day generally are consuming at least as many or more calories as those who never smoked yet have lower weight.