The relation of cigarette smoking and alcohol use to diet was examined in a general population of adults ages 20-59 years enrolled in the Lipid Research Clinics (LRC) Prevalence Study. There was a positive association between cigarette and alcohol use, but little relation between these habits and the nutrient intake. The total energy from food was about the same whether or not a person drank or smoked; alcohol was simply added to food intake. However, persons who drank received slightly less of their food energy from carbohydrate than persons who did not drink and persons who smoked received slightly more of their food energy from fat than did nonsmokers. Both persons who drank and persons who smoked weighed less than would be expected from their total energy intake. While these relationships were similar for men and women, among women they were stronger for those using gonadal hormones than among those not using these hormones.