Archive 2007 2008 2009 2010

Q: Do I need to eat more protein if I exercise?

A: Chances are you already get more than enough protein, even if you are a vigorous exerciser. The Recommended Dietary Allowance (RDA) for adults is 0.8 grams of protein a day for each kilogram (2.2 pounds) of body weight. That’s 64 grams of protein for a 175-pound man and 47 grams for a 130-pound woman (an ounce of chicken or peanuts or cup of milk has about 8 grams).

If you exercise regularly you may need a little more protein than the RDA, but most Americans already get more than that; many get twice the RDA without trying. Even weight-lifters and endurance athletes generally get enough protein, simply because their higher-calorie diets supply it. (Athletes on low-calorie diets and people who eat no animal foods may need to make more of an effort, though.)

Some studies suggest that the timing of your protein might make a difference, however. While eating carbohydrates immediately after intense exercise replenishes glycogen (the storage form of glucose, used as fuel during exercise), adding a little protein to the mix seems to benefit muscle as well.

A study in the Journal of Physiology a few years ago, for example, found that older men who consumed protein right after resistance training developed more muscle after 12 weeks, compared to men who had the protein two hours after exercising. And a study at McMaster University in Canada this year found the proteins in skim milk (casein and whey) particularly effective in stimulating muscle growth after resistance training in young men—more so than soy milk protein. Other studies show that post-exercise protein reduces muscle damage. Whether this makes much difference in athletic performance is debatable, but it can’t hurt to have a cup of skim milk or yogurt after a workout.

Keep in mind: Consuming more protein than your body needs does not build more muscle. Only exercise, specifically strength training, does.

Q: I’ve heard that too much copper can be harmful. Is the amount in a basic multivitamin safe?

A: Yes, in fact, if you take a multi, it should contain 100% of the Daily Value for copper. This trace mineral is an essential component of enzymes that assist in energy production, nervous system functioning, wound healing, bone health, and other body processes.

You may be referring to a few studies that have linked high copper levels to an increased risk of cardiovascular disease and cognitive decline in older people. But unless you have a problem in copper metabolism (as in the inherited Wilson’s disease), getting too much copper should not be a concern. Far more people get too little than too much. Low copper levels have been linked to arthritis, cancer, osteoporosis, depressed immunity, and neurological problems. Some experts think a copper deficiency increases the risk of heart disease, and some research suggests that copper supplementation may actually slow Alzheimer’s disease.

But don’t go overboard: a multivitamin shouldn’t supply more than 100% of the Daily Value for copper and other nutrients. Don’t take high-potency formulas or copper supplements. A healthy diet will include many copper-rich foods—nuts, seeds, shellfish, whole grains, avocados, and legumes (such as lentils).

Q: When I get a cocktail in a restaurant it’s usually very large. Am I consuming more than a standard serving of alcohol?

A: Most likely. Cocktails have been supersized. While a "drink" of 80-proof liquor is defined as 1.5 ounces—not much, just 3 tablespoons—a cocktail at a bar or restaurant usually contains considerably more. If a martini is 4 ounces, for example, that counts as almost three drinks.

It’s also easy to pour with a heavy hand at home, as the size and shape of a glass can be deceiving. In a British Medical Journal study in 2005, college students asked to pour 1.5 ounces of liquor into a short, wide tumbler overshot by 30%, but were pretty accurate when they used a tall, narrow highball glass. To see exactly how big your normal portion is, use a measuring cup.

Moderate alcohol intake is defined as no more than one drink a day for women and two drinks for men. A standard drink is also 12 ounces of beer or 5 ounces of wine; all contain about the same amount of pure alcohol (0.6 ounces). People who drink in moderation have lower mortality rates, especially from heart disease, compared to teetotalers, occasional drinkers, and heavier drinkers. You can still be a moderate drinker if you have a supersized cocktail on occasion, but overdoing it on a regular basis increases the risk of health problems.

UC Berkeley Wellness Letter, November 2007