Q: Can coffee negatively effect my fat burning?

A: When you drink a cup of coffee or can of cola, the caffeine is absorbed throughout your body. The liver must detoxify this caffeine without the aid of your kidneys. The kidneys attempt to excrete the caffeine molecules via the urinary tract, but they are reabsorbed into the bloodstream too fast. Thus, the liver must detoxify the caffeine alone.

Women are particularly vulnerable to the effects of caffeine. Research has shown that women detoxify caffeine more slowly than men. Studies comparing caffeine’s effects on men and women found that women performed less well on cognitive tasks and rated themselves as more tired and disorganized than men did within one hour of a dose of caffeine. This may result not only from more caffeine remaining in a woman’s body longer but also from hormonal interactions with caffeine. If a woman is also taking birth control pills, she will need about twice the average time to detoxify any caffeine she consumes.

Caffeine actually helps extend cortisol secretion, besides promoting metabolic imbalances. Just 15 ounces of your favorite coffee contains enough caffeine to raise your epinephrine level by more than 200 percent. And that epinephrine pumps out more stress hormones, including cortisol. Chugging around three cups of coffee a day could cause your serum cortisol to stay at high levels eighteen out of every twenty-four hours, instead of just the couple of hours our bodies were designed to handle. Caffeine also promotes norepinephrine production. This stress hormone targets your nervous system and brain. Along with epinephrine, it increases your heart rate, raises your blood pressure, and stimulates your “fight or flight” stress response. In fact, caffeine actually reduces your threshold for stress so that you aren’t able to handle it well. This might force you to cope by eating more comfort foods (invariably loaded with sugar and other high-glycemic carbohydrates), which creates more metabolic stress and fat storage.

You may be thinking, “I only drink one or two cups of coffee a day.” However, you may be unknowingly consuming much more caffeine, from chocolate, cocoa, tea, some soft drinks, kola nut and guaraná root supplements, and a host of over-the-counter medications, including Excedrin, Anacin, Vanquish, Midol, Cope, Premens, Vivarin, NoDoz, and Dexatrim.