12 Diet Facts Revealed

Authors of the bestselling You: The Owner's Manual help sort fact from fiction.

By Michael F. Roizen | M.D. and Mehmet C. Oz from Reader's Digest


  • 6.

    Cracking your knuckles will cause arthritis.

    False. It makes you sound like a bowl of Rice Krispies and never goes over well in church. While it’s painful for us to hear, you’re not doing any harm to your joints, bones or muscles when you crack — unless you feel pain as you do it. The noise is caused by the high-pressure suction of gas being expelled when your joints move apart. If it hurts when your knuckles or knees crack, you need to see your doctor to assess what kind of joint damage you may have.

  • 7.

    Men can drink more than women.

    True — but not for the reason you think. It doesn’t have anything to do with machismo. Men have an enzyme that metabolizes more of the alcohol they drink before it even hits the bloodstream. Women don’t have as much of that enzyme in their gut walls. Their bodies also contain less water than men’s do, resulting in higher blood-alcohol levels drink for drink.

  • 8.

    Blood in the toilet means you have cancer.

    Probably not. A small amount of bright red blood is usually nothing to be alarmed about. It most likely indicates hemorrhoids, and just a single drop of blood can turn the whole bowl red. Check with your doctor to be safe. You can detect microscopic levels of blood, which could signal something more serious, with an at-home test called Hemoccult. It’s available at pharmacies. Don’t worry; it’s not as gross as it sounds. Just follow the directions on the label.

  • 9.

    You can 'spot reduce' a specific problem area.

    False. Let’s say you have a gut, or some cellulite on your thighs. Do crunches or squats every day and you’ll eventually work off the fat, right? Sorry. That’s not how the body works. Think about when you see someone who’s lost weight. Where’s the first place you notice it? The face. Since we don’t see too many people doing face crunches in the gym, it just goes to show that your body dictates where fat is burned. If you want to build muscle in a particular area, you can make it look younger and firmer. But the only way to target a trouble spot is through an overall program of aerobic exercise, resistance work and a calorie-controlled diet. You have to lose it under the chin to lose it from your belly.

  • 10.

    For diarrhea, the best cure is waiting it out.

    False. The best solution isn’t setting up camp on the toilet and waiting for the deluge to run its course. It’s chicken soup with rice. That combination of rice and broth seems to break down certain sugars that, along with sodium, suck water back into your system, offsetting the dehydration caused by Old Faithful.

  • 11.

    Hormones control your emotions.

    Usually false. Pregnant women may disagree, but it’s actually more often the other way around. Emotions control your hormones through biochemical changes in the brain. Fear, for instance, is accompanied by the production of one set of brain chemicals that can make you alert and ready to flee, while pleasure triggers the release of other chemicals that soothe and calm. Stress can cause a sustained production of stress hormones, which can then damage the hippocampus, a part of the brain that’s crucial to learning and memory.

  • 12.

    You can take a vitamin instead of eating.

    Sometimes true, as, for instance, with calcium supplements (with vitamin D). But don’t be misled into thinking that it’s better to down pills than to down vegetables. Orange juice has more in it than just vitamin C. And foods don’t just have a biochemical importance; they can create a kind of energy force in your body. For example, it may be that it’s not one nutrient that helps prevent cancer or reduce heart disease, but rather the combination of several ingredients that does the trick. And that’s the kind of nutritional power you find only in the way nature makes our food. In fact, we believe that the study of how food can heal is the next frontier in medicine.

Adapted from “You: The Owner’s Manual” copyright © 2005 by Michael F. Roizen, M.D., and Mehmet C. OZ, M.D., published at $24.95 by HarperResource, an imprint of HarperCollins Publishers, Inc., 10 E. 53rd St., New York, N.Y. 10022

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