The effects of cigarette smoking and food consumption on the metabolic rate in adolescent females
Hickox, Kimberly Dawn
This study assessed the metabolic effect of cigarette smoking and food intake alone and in combination in a group of habitual young smokers ( 16.78 Â± 0.67 yrs). Nine females were presented, over four non consecutive days, with the following randomized conditions: (1) consumption of a 700 kcal high carbohydrate (CHO) meal (60% CHO, 15% Protein, 25% Fat); (2) inhalation of two cigarettes; (3) inhalation of two cigarettes preceded by the consumption of a 700 kcal high CHO meal (60% CHO, 15% Protein, 25% Fat); (4) no cigarettes nor food consumption. Resting energy expenditure (REE) was measured by indirect open-circuit calorimetry prior to the treatment, immediately following each intervention, and for four consecutive hours thereafter. The results showed that the individual and combined effects of cigarette smoking and food consumption significantly increased (p < 0.05) REE above pre-treatment, and remained elevated across the five post-treatment time periods. For the no smoking/no food condition, REE did not increase from baseline and showed little change across the five post-treatment time periods, indicating minimal diurnal variation in REE for this control condition. No significant difference in REE existed among the conditions of smoking, food consumption, and food consumption/smoking at any time period. The findings from this investigation showed that the two thermogenic stimuli of smoking and eating (alone and in combination) increase the resting energy expenditure in a group of young female smokers. These increases in energy expenditure were larger in magnitude than was observed in previous studies conducted with the adult population, therefore it was suggested that the metabolic responses of adolescent females to thermogenic stimuli may be heightened when compared to adults. It was also suggested that cigarette smoking may increase the duration of the thermic effect of food (TEF).