QUESTION: Low-fat latte is one of my favorite treats, and I justify it to myself because I get a serving of low-fat milk, which is a good souce of calcium.Then I was told by a friend that coffee blocks the absorption of nutrients, and that I really can't rationalize this bad habit if I want to have a healthy lifestyle. Is this true?ANSWER: It's true that the nutritional effects of coffee are a mixed brew.Caffeine — a primary ingredient in coffee — interferes with the absorption of minerals such as iron and calcium.On the positive side, caffeine stimulates the release of fat so the body can burn it for energy — a boost for endurance athletes.More confusing than a double non-fat cappuccino are recent studies that look at the health effects of drinking coffee. Some ingredients in coffee increase the risk for heart disease; others decrease risk.Reports from several epidemiological studies in the Journal of the American Medical Association found that people who drank four to six cups of coffee a day had a 28 percent lower risk of type 2 diabetes than those who drank less.And two prospective studies in the International Journal of Cancer found an association between higher intakes of coffee and a lower incidence of liver cancer.All in all, coffee is not seen as a bad habit unless you don't understand "moderation." In coffee terms, that's about one or two regular-strength cups of java a day.A typical 8-ounce cup of coffee contains about 200 milligrams of caffeine. More than 300 to 400 milligrams of caffeine a day can cause you to lose the amount of calcium in 2 teaspoons of milk. Enjoy your low-fat latte.

QUESTION: If alcohol has no fat, no protein and little or no carbs, but there are around 100 calories in a serving, then where do those calories come from?I remember ninth-grade biology: Carbs and protein are both around 4 calories per gram and fat is around 9 calories per gram. So if the calories don't come from any of those, what do they come from?ANSWER: Your biology teacher taught you well. Calories in food come from protein, fat and carbohydrates (sugars and starches). Calories in alcohol come from alcohol.Alcohol has zero nutritional value, but it still contains calories — a perfect "empty calorie" food.Ethanol, the alcohol in beer, wine and other spirits, yields 7 calories per gram, more than carbohydrates and protein, less than fat. And those calories are absorbed into your bloodstream quicker than you can say, "Who's the designated driver?"Alcohol has been called the nutritional "Jekyll and Hyde." Moderate intake may have some beneficial effects, including a lower risk for heart disease. In excess, it is toxic to the liver and interferes with the body's use of nutrients.Even moderate amounts of alcohol (one to two drinks a day) can change the shape of your body and your health, however.Extra calories from alcohol are easily converted to fat that tends to reside around your middle — the place that increases your risk for heart disease and diabetes.Barbara Quinn is a registered dietitian at the Community Hospital of the Monterey Peninsula, Calif. Readers may send her an e-mail at bquinn@chomp.org.