Energy intake and energy expenditure during the menstrual cycle in short-term smoking cessation

The effect of short-term smoking abstinence on energy intake and expenditure parameters was investigated for women in different phases of the menstrual cycle (follicular or late luteal) in a rigorous inpatient laboratory setting. Twenty-one participants were randomized to a continued smoking (n = 5) or a smoking abstinence (n = 16) group and admitted for 2 7-day inpatient periods during alternate cycle phases. The smoking abstinence group experienced 2 days of baseline smoking and 5 days of smoking abstinence. Measurements included caloric intake (kcal/24 hours), energy expenditure (by indirect calorimetry), and weight. Results of within-subject analyses indicated no smoking abstinence effect on mean daily total kilocalorie intake, sweet kilocalorie intake, or resting metabolic rate. However, a significant cycle phase effect was observed, with increased kilocalorie intake and expenditure-as well as minor weight gain-occurring during the late luteal phase when premenstrual symptoms are highest. In light of this phase effect, women smokers might benefit by attempting to quit smoking during the follicular phase of their cycle.