Probably nothing you do to control your weight is as important as keeping your liver healthy. This means avoiding as many of the damaging elements (like alcohol) as possible while embracing liver boosters. Among the lesser known compromisers of liver function are caffeine, sugar, trans fats, medications, and inadequate fiber.

Caffeine. In his landmark book, Caffeine Blues, researcher and nutritionist Stephen Cherniske, M.S., addresses a dozen critical organs and processes affected by caffeine. Right now, I'll focus on the liver, but I'll have more to say about caffeine later in this chapter.

When you drink a cup of coffee or can of cola, the caffeine is absorbed throughout your body. According to Cherniske, 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. And remember, as I mentioned in the section on the liver toxicity factor, caffeine is in much more than coffee. It's found in over-the-counter medications (e.g., Excedrin, NoDoz, Dexatrim, Anacin, Vivarin, and Vanquish), chocolate (e.g., baking chocolate, cocoa, and milk chocolate), sodas (e.g., Pepsi, Mountain Dew) and tea.