Calorie restriction increases cigarette use in adult smokers

Cigarette smokers weigh less than nonsmokers, and smokers often gain weight when they quit. This is a major barrier to smoking cessation, especially among women. However, strict dieting is not recommended during smoking cessation out of concern that it might promote relapse. This concern derives, in part, from the observation that calorie restriction increases self-administration of drugs of abuse in animals. This relationship has never been experimentally demonstrated in humans. To evaluate whether calorie restriction increases cigarette smoking in humans. Seventeen (nine males, eight females) healthy, normal-weight smokers not attempting to quit were cycled in partially counterbalanced order, double-blind, through four diets-normal calorie (2,000-2,800 kcal/day), low calorie (700 kcal/day deficit), low-carbohydrate (CHO)/normal-calorie, and low-CHO/low-calorie-for 6 days per diet in an inpatient research ward. Smoking was assessed by cigarette counts, breath carbon monoxide (CO) levels, and cigarette craving. Compared with the normal-calorie diet, while on the low-calorie diet, subjects smoked 8% more cigarettes (P < 0.02) and had 11% higher breath CO levels (P < 0.01). The low-CHO/normal-calorie diet showed no significant effect on either variable, but there was a 15% increase in breath CO levels (P < 0.05) on the low-CHO/low-calorie diet. There were no changes in self-reported cigarette craving or mood. Consistent with animal studies, moderate calorie restriction was associated with a small but statistically significant increase in cigarette smoking, with no independent effect of CHO deprivation. These findings suggest that dieting may increase smoking behavior and could impede smoking-cessation attempts.