Metabolism refers to the body's process of converting food into energy by combining it with oxygen. Your metabolism determines the number of calories your body needs, even for basic processes such as breathing and blood circulation. Metabolism is affected by several factors, including smoking. The nicotine in cigarettes has a stimulating effect on the body, which might increase energy expenditure.
Metabolic Rate Increase
Smoking stimulates the central nervous system, heart and respiratory functions. According to the "American Journal of Clinical Nutrition," smoking a cigarette creates a 3 percent increase in the energy expenditure of the metabolic rate, and smoking four cigarettes increases it by 3.3 percent for up to three hours. a smoker going through 24 cigarettes each day may increase his daily energy expenditure by about 15 calories.
Inconsistent Results
Not all research indicates that smoking has a significant impact on metabolism. In 2010, researchers at the University of Wisconsin conducted one of the largest studies to date on the energy expenditure associated with smoking. Their research found no significant difference in the metabolic rates of smokers and nonsmokers. Decades of research on the relationship between smoking and metabolism have provided inconsistent results. Some of the work suggests a strong correlation between smoking and increased metabolism, and other studies show no significance.
Weight
Although research results are inconsistent, the higher metabolic rates found in some research suggests smokers should have a lower risk of becoming overweight. The "American Journal of Clinical Nutrition" reports, however, that daily smoking correlates with a high risk of becoming overweight or obese. The cause of this apparently contradictory relationship between increased metabolism and weight gain is difficult to identify. It's likely that the long-term negative health impact of smoking more than negates any small metabolic increase associated with nicotine's stimulating influence.
Indirect Influences on Metabolism
If smoking does have a direct impact on metabolism, it comes from the short-term stimulating effect of nicotine. Other indirect influences on metabolism come from long-term damage caused by other chemicals in cigarette smoke and overstimulation from nicotine. The extra stress placed on a smoker's heart significantly increases the risk of developing heart disease, and tar accumulation in the lungs reduces respiratory efficiency. Regardless of exactly how much it affects metabolism, any amount of short-term metabolic advantage is quickly lost to the long-term detrimental effects of smoking.
References
- "The American Journal of Clinical Nutrition"; Consequences of smoking for body weight, body fat distribution, and insulin resistance; Arnaud Chiolero, et.al.; April 2008
- Mayo Clinic: Metabolism and weight loss How you burn calories
- "Nutrition and Metabolism"; Effect of smoking status on total energy expenditure; David P. Bradley, et. al.; November 2010
