Does Coffee Increase Your Metabolism?

For roughly half of American adults, coffee is a daily indulgence. If you are a coffee lover, you are familiar with its mildly stimulating effect, which is due to the caffeine in coffee beans. The physiologic actions of caffeine are complex and involve several of your organ systems. A modest increase in metabolic rate is one of the well-known effects of caffeinated coffee. Some weight-reduction programs encourage coffee consumption to capitalize on this metabolic effect.

Thermogenesis

All activities of your body require energy, including the digestion, absorption, processing and storage of food. This energy expense, known as the thermic effect of food or diet-induced thermogenesis, accounts for approximately 10 percent of your total daily calorie expenditure, note Dr. C. Ronald Kahn and colleagues in the text, "Joslin's Diabetes Mellitus." Caffeine from coffee and other sources increase the number of calories burned by diet-induced thermogenesis.

Dose-Related Response

The amount of caffeine you consume from coffee or another source affects the magnitude of increase in your metabolic rate. In a January 2009 article published in the European Journal of Clinical Nutrition, nutritionist Anita Belza and fellow researchers report that a 50 mg dose of caffeine --- roughly half the amount in an cup of coffee --- increases metabolic rate by approximately 6 percent. In an earlier study published in the American Journal of Clinical Nutrition, Dr. Arne Astrup and colleagues showed that the thermogenic response progressively increases with doses of 100 mg, 200 mg and 400 mg of caffeine. It is unclear whether the dose-response relationship between caffeine and thermogenesis plateaus at higher levels of consumption.

Obesity Effects

Obesity may blunt the effect of caffeine on your metabolic rate. In an October 1995 article published in the American Journal of Physiology, Endocrinology and Metabolism, Dr. David Bracco and coauthors reported that lean women experience a greater increase in diet-induced thermogenesis in response to caffeinated coffee compared to obese women. Additionally, the increase in metabolic rate persists for a longer period in lean women compared to obese women. The findings of Bracco and colleagues confirmed earlier work by Kevin Acheson and coinvestigators published in 1980 in the American Journal of Clinical Nutrition.

Considerations

The modest increase in your metabolic rate associated with drinking caffeinated coffee may help support your efforts to maintain a healthy body weight or lose extra pounds. Excessive consumption of caffeinated coffee or another source of caffeine, however, may have adverse effects including jitteriness, sleeplessness, increased urination, tremors and a rapid heart rate. Talk with your doctor if you have questions about your level of coffee consumption.