Effects of a 24-hour fast on cigarette smoking in humans.

The effects of 24 hours of food deprivation on cigarette consumption, smoke exposure and mood were studied in seven research volunteers. A within-subjects design was used in which subjects smoked low-yield (0.1 mg nicotine) and high-yield (0.7-1.1 mg nicotine) cigarettes in both a fed and a fasting state. Each of the four experimental conditions--FED/LOW-YIELD, FED/HIGH-YIELD, FAST/LOW-YIELD, FAST/HIGH-YIELD--was enacted twice according to a randomized block design. Cigarette consumption was measured during the 24-h period before experimental sessions. The session included a 60-min smoking period, in which number of puffs per cigarette, number of cigarettes smoked, carbon monoxide (CO) exposure and mood were assessed. Although cigarette consumption during the 24 h prior to sessions did not vary as a function of feeding condition, CO levels at the end of this 24-h time period were slightly, but significantly, higher in the FAST condition (mean CO level: 30.3 ppm) than in the FED condition (mean CO level: 28.1 ppm). During the laboratory session, amount of smoking and CO exposure were similar across feeding conditions. Interactions between feeding condition and dose were obtained on several mood measures that reflected sedation and arousal: in the high-yield condition, subjects were more sedated after fasting, whereas in the low-yield condition, they reported being less sedated after fasting. We conclude that fasting does not alter cigarette consumption but may increase smoke exposure during ad libitum smoking, perhaps via a change in some aspect of smoking behaviour not measured in the present study (e.g. puff volume).