The present research was designed to assess the amount of weight gain that would occur when male smokers in an inpatient setting were deprived of cigarettes for 10 days, and to evaluate factors that could contribute to that weight gain, such as caloric intake and activity level. Subjects were 17 healthy male smokers who either smoked ad libitum (n = 8) or quit smoking (n = 9) for 10 days after a 3 day smoking baseline. Caloric intake, activity levels, and body weight were assessed daily. Abstainers gained more weight than did smokers and ate more over time. There were no group differences in activity level. An analysis of energy needs versus actual energy intake suggests that caloric intake accounted for a large percentage of the post-cessation weight gain. However, considerable individual variability exists in caloric intake after smoking cessation. In addition, the study found post-cessation increases in caloric intake that were quite similar to those found in studies with females, suggesting that gender may have little to do with overall post-cessation caloric intake. Further research assessing dietary and metabolic changes after smoking cessation in a larger sample of both males and females is needed so that the reasons for and implications of dietary variability can be evaluated.