The objective of this study was to examine differences in the nutritional intake of seronegative (SN) and seropositive (SP) AIDS-free subjects within a cohort of gay men. The nutritional intake of 145 SN and 139 SP subjects between October 1991 and September 1992 was evaluated using a self-administered 24-h dietary recall questionnaire. The calorie and nutrient content of all food items eaten in a day was coded using the Canadian Nutrient File database. SP subjects were estimated to have been HIV positive a median of 8 years (range, 0.5-9.8 years) and were AIDS-free as of November 1992. SP subjects were younger (median 38 versus 41 years; p = 0.009) and had lower body mass index (BMI) (median index 23.5 versus 24.5; p = 0.017). No significant differences was observed between the two serologic groups in regard to weight change over the previous year. Total caloric intake was significantly higher in the SP group (median, 2,198 versus 1,971 kcal; p = 0.019). SP subjects had higher intakes than SN subjects of protein (median, 94 versus 81 g; p = 0.011), fat (median, 79 versus 66 g; p = 0.023), carbohydrates (median, 240 versus 216 g, p = 0.032), and cholesterol (median 317 versus 252 mg; p = 0.017). These differences persisted after adjustment for age and BMI. In the SP group, there was no difference in caloric intake between those with CD4 counts above and below 200. HIV-infected individuals appear to have a caloric intake higher than that of HIV-negative homosexual controls from the same cohort.(ABSTRACT TRUNCATED AT 250 WORDS)