Weekly Column_120 / August 16, 2012

Diet Detective Nutrition and Fitness Questions Answered: Pumpernickel Bread, Sweating, Lobsters and Weights

By Charles Platkin, PhD

Is pumpernickel bread better than white bread?

That depends. Is it real pumpernickel bread? Traditional pumpernickel bread, with its German roots, is made from ground up rye and is dark in appearance. And the fact that traditional pumpernickel is made with a whole grain (rye) is exactly why people believe it is healthier than white bread. However, the bread you’re eating likely is not real German pumpernickel. What most people eat is made from white flour and a coloring and/or sweetener such as molasses or caramel. It’s also pretty similar in calories to other breads. Your best bet is to look for 100 percent whole-wheat bread without added sugar. Or try authentic pumpernickel bread such Mestemacher, which is available from Amazon.com.

If I sweat more when I’m working out, does that mean I’m losing more weight?

Unfortunately, sweating doesn’t mean that you’re burning calories. Sweating is the way your body cools itself. People sweat because their body temperature increases. Oftentimes, when you work out your body temperature goes up, and that’s why sweating is associated with exercise. But that’s where the relationship ends. It’s a real mistake to monitor your level of exercise based on how much you’re sweating, because excessive sweating can bring on heat exhaustion, followed by heat stroke. If you want to measure your physical activity level, there are a few better methods you can use: a heart-rate monitor, the Borg Rating of Perceived Exertion or the talk test. The talk test is a simple way to measure exercise intensity. According to the Centers for Disease Control and Prevention: “As a rule of thumb, if you’re doing moderate-intensity activity you can talk, but not sing, during the activity. If you’re doing vigorous-intensity activity, you will not be able to say more than a few words without pausing for a breath.”

Are lobsters healthy or not? I’ve heard that they’re not good for you.

First of all, “good” is always relative in terms of health. However, in general, lobsters are a pretty healthy choice. A 6-ounce serving of meat (about a 1 1/4-pound to a 1 1/2-pound lobster) has 167 calories, 34.9 grams protein, 2.2 grams carbs and 1 gram fat. There is virtually no saturated fat, and lobster is loaded with vitamin B12, selenium and copper. Selenium helps regulate thyroid function and boosts the immune system. Vitamin B12 is necessary for red blood cell formation and neurological function, as well as DNA synthesis.

In terms of dietary cholesterol, 6 ounces of lobster has 120 milligrams, or about 40 percent of the recommended daily value. Should you be concerned? First, you need to know the difference between dietary cholesterol and blood cholesterol. These two things are not the same at all. Our bodies produce cholesterol naturally. And it turns out that dietary cholesterol is less of a concern than foods that are loaded with saturated fat. However, that doesn’t mean you don’t need to worry about dietary cholesterol. According to the National Institutes of Health’s National Heart, Lung, and Blood Institute (NHLBI): “Higher intakes of dietary cholesterol raise serum LDL cholesterol levels in humans. Through this mechanism, higher intakes of dietary cholesterol should raise the risk for coronary heart disease. Reducing cholesterol intakes from high to low decreases serum LDL cholesterol in most persons.” The American Heart Association recommends an intake of 300 milligrams or less of dietary cholesterol a day.

Do I need to use heavy weights to build muscle?

Not necessarily. A recent study conducted at McMaster University in Canada showed that a similar degree of muscle building can be achieved by using lighter weights as compared to the traditional theory that you need heavy weights. Nine men were tested to determine the maximum amount of weight they could lift. The men were then divided into two groups. One group lifted weights set at 90 percent of their best lift, and the other group used weights set at a mere 30 percent of what they could lift. The results showed similar muscle growth in both groups. And while the study is small in terms of the number of participants, it still has merit. “I am not too surprised by this result as I have always stipulated that muscle responds best to time under tension (amount of time the muscle spends under contraction), a function of volume (sets and reps), and this study verified it,” says Fabio Comana, M.A., M.S., an exercise physiologist for the American Council on Exercise.

But while Comana agrees with the findings, he believes that working with weights at only 30 percent of your maximum is too little because it would require much more time to work the muscles to exhaustion. Most experts agree that when you’re trying to build muscles, the number of repetitions, sets and the intensity are not as important as taking the muscle to complete exhaustion ­ meaning that you literally can’t do another repetition. The reason is that working your muscle to exhaustion actually causes microscopic injuries to the muscle, and as it repairs itself, it becomes stronger by building larger fibers to prevent future injury.

That is how you sculpt your body. Using weights helps because it takes much longer to exhaust the muscles through calisthenics or other types of exercise. Comana also believes that it’s important “to integrate more whole body movements (i.e., push-press, cleans, etc.) vs. muscle isolation (curls) as they add metabolic shock and caloric burn as well as a cardio element.”

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