Effects of Cigarette Smoking on Body Weight, Energy Expenditure, Appetite and Endocrine Function

摘要

It is a common belief that people tend to gain weight on stopping smoking. For fear of gaining weight they may continue to smoke and thus retain a significant risk factor for cardiovascular and pulmonary disease. We have studied 4 lean young men who habitually smoked a pack of cigarettes a day. Food intake was kept constant throughout the study, which incorporated periods of smoking and non-smoking in an on-off-on design. The relative importance of change in hunger, in hormonal responses, plasma substrate concentrations, appetite and metabolic rate were thus assessed. Only small, statistically insignificant fluctuations in weight occurred during the course of the study. In 3 of 4 subjects, weight was increased during the period of non-smoking by 0.9 kg and decreased after resumption of smoking by 1.2 kg. During standardized walking exercise in the non-smoking period, the heart rate was significantly lower than during the periods of smoking. There were no changes in resting or walking metabolic rate observed to support any significant decrease in energy expenditure during the non-smoking period. Appetite ratings nearly doubled (p <0.01 at that time, however. The TSH response to TRH was significantly suppressed during the two periods of smoking, which may reflect a central effect of smoking; the response of prolactin to TRH was not affected.