Why is Good Nutrition Important
What’s Really Important in Nutrition?
Not all that many years ago, nutrition experts told us to avoid fattening sugar and starch. Now they’re telling us to load up on starch, but never, never eat fat. What, you might well ask, is going on here? And why should anyone bother paying attention?
The self-appointed “food police” can turn any meal into a minefield. We’re told to avoid Chinese, give up guacamole, eat our popcorn dry. But here’s the good news about all of this: None of it is invariably true. If you talk to an authentic nutritionist, you’ll find that there’s plenty of stuff you can eat at the Peking Garden, and a way to have your buttered popcorn too.
Despite the confusion, we really do know more about nutrition today than ever before—and the basic facts turn out to be surprisingly simple. Moderation and balance are crucial. Everything else is a detail. The rest of this discussion is given over to those details, sorting out what really matters in nutrition, and highlighting ways to upgrade your diet for a healthier life.
The government has incorporated most of the nutritional facts we’re sure of into two excellent tools—the “Nutrition Facts” labels and the Food Guide Pyramid. The food labels are designed to pinpoint what’s really important for most Americans. Experts now agree that most of us eat too much fat, saturated fat, cholesterol, sodium, and sugar, and may not be getting enough starch and fiber—and these are what you’ll find highlighted on the labels.
These nutrients have been singled out not only because they are problem areas, but also because they are the focus of some of the strongest evidence available on the way food affects our health. We are as certain as science can be, for example, that, for many people, a high-fat, high-cholesterol diet can lead to heart disease and stroke. The nearby box, “Certain enough to be allowed on food labels,” lists health claims with enough evidence behind them for the U. S. Food and Drug Administration (FDA) to allow them on labels.
Daily Values: What the Government Recommends
In setting these amounts, the U.S. Food and Drug Administration assumed an average diet of 2,000 calories a day.
|saturated fatty acids||
5,000 International Units
400 International Units
30 International Units
Source: Guidance for Industry: FDA Nutrition Labeling Manual—A Guide for Developing and Using Data Bases, U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition. 1998 Edition.
As part of the nutritional labeling, the government has set recommended Daily Values (DVs) for many of the nutrients considered most important (see the table nearby). It has also adopted the rule of thumb that about 60 percent of our food should be carbohydrates (bread, rice, pasta, fruits, and vegetables are mostly carbohydrates), 30 percent fat (including 10 percent saturated fat), and 10 percent protein. By law, food labels now tell you not only how many grams of fat a serving has, for example, but how much of your Daily Value of carbohydrates, fat, and protein it delivers. A food that packs 50 percent of your recommended daily fat allotment in one serving, for example, should give you pause. You don’t have to pass it up—but you may want to compensate for it by loading the rest of your menu with low-fat options.
THE FOOD GUIDE PYRAMID
The Food Guide Pyramid, issued by the U.S. Department of Agriculture, translates the 60 percent carbohydrates, 30 percent fat, 10 percent protein guideline into servings of specific types of food. The biggest difference between the pyramid and its predecessor, the Basic Four Food Groups, is that meat is no longer the centerpiece of a meal. Instead, rice, pasta, or other grains, along with fruits and vegetables, are supposed to account for the bulk of our food. This is because grains, fruits, and vegetables are high in fiber, carbohydrates, and needed vitamins and minerals, and gratifyingly low in fat. Meat has not been banished from a healthy diet, but most of us eat far more of it than we actually need, while short-changing ourselves on grains, fruits, and vegetables.
The pyramid was released in 1992, and polls indicate that most Americans are aware of it. The polls also show that we don’t follow it. An August 1994 survey of 372 households by Parade magazine found that those questioned ate an average of 3.4 servings from the grain group per day, although the pyramid calls for 6 to 11. Other reports show that, from day to day, most of us eat about half of the 2 to 4 servings of fruit and the 3 to 5 servings of vegetables the pyramid recommends. Many of us go all day without eating any fruits or vegetables. And, despite everything we’ve been told, most of us still eat too much meat, too many dairy products, and excessive amounts of all the other things the experts warn against.
Certain Enough To Be Allowed On Food Labels
Ironically, it’s now easier than ever to upgrade your diet if you’re so inclined. Food labels make it a cinch to tell what’s actually in the food you buy; and you don’t have to calculate each ingredient to the last calorie. Instead, just keep these five general guidelines firmly in mind.
- 1. Cut Back on Fat and Cholesterol
- 2. Cut the Calories (If You’re Overweight)
- 3. Slow Down on the Salt
- 4. Boost Your Carbohydrates
- 5. Don’t Worry about Protein
- Is the “Mediterranean Diet” Better than the USDA Food Pyramid?
- Is Fat Intake Linked to Breast, Colon, Lung, Prostate, and Bladder Cancer?
- Is Alcohol Linked to Cancer?
- Is Red Meat Linked to Colon and Prostate Cancer?
- Can Grilling Meat at Very High Temperatures Create Cancer-Causing Compounds?
- Is Plant Protein Better than Animal Protein?
- Is Salt Linked to Stomach Cancer?
- Are Recommended Daily Allowances Too Low?
- Does Sodium Cause High Blood Pressure?
- Does Fish Oil Help the Heart?
- What To Look For On Labels
- Protein Does Not Promote Osteoporosis
- Too Much Protein Does Not Cause Kidney Disease
- Too Much Protein Does Not Cause Cancer
- Oat Bran Does Not Slash Cholesterol
- Starchy Foods Are Not Fattening
- What a “Balanced Diet” Means Today
The experts recommend that we get no more, and preferably less,than 30 percent of our calories from fat. That 30 percent includes 10 percent from saturated fat and 10 percent from polyunsaturated fat. We also should limit cholesterol to 300 milligrams a day. Right now, most of us get 35 percent to 40 percent of our calories from fat.
In susceptible people (and there’s currently no way to tell whether or not you’re susceptible), fat is conclusively linked to heart disease and perhaps to cancer as well (for information about the possible cancer link, see the “Promising Theories” section below). A high-fat diet is also associated with stroke and high blood pressure. Excessive fat intake raises cholesterol levels, and high cholesterol leads to the clogged arteries found in victims of heart disease, heart attack, and stroke.
It’s especially important to eat less saturated fat. Meat (both red meat and poultry) and whole milk are the two main sources of saturated fat for most of us. Meat also accounts for 30 percent of the cholesterol in most people’s diets, and there is no good substitute for cutting down on cholesterol. Niacin, a B vitamin, has been shown to reduce cholesterol; but, when used in high doses, it has potentially dangerous side effects, including flushing, rashes, impaired liver function, higher blood sugar, and stomach and intestinal problems. Likewise, cholesterol-lowering drugs are reserved for serious cases and are available only by prescription.
In contrast, there are plenty of simple, relatively painless ways to cut the fat in your cooking. Here are five tips from Consumer Reports on Health.
Five Rules To Remember
Don’t use fat as a flavoring. Let’s face it—fat is tasty, and a pat of butter or margarine on your bread or vegetables may not seem like much. But nutritionists warn that these little extras add up quickly. As a substitute for butter or margarine, try baking garlic in the oven for 1 hour with a little bit of olive oil, then using it on bread or pasta. It comes out with a spreadable consistency. Herbs or lemon juice can season vegetables. If you must use fat, try olive oil instead of butter.
Eat less meat. Reducing or eliminating meat from recipes such as spaghetti sauce greatly lowers their fat content. Try using vegetables and herbs in casseroles and other combination recipes where you might once have used meat. Let pasta, rice, and fruits and vegetables step in as the mainstays of your meal. A serving of meat should be no more than 3 ounces—the size of a deck of cards or a woman’s palm. Remember that the pyramid recommends only 2 to 3 servings a day from a group that includes eggs, beans, nuts, poultry, and fish along with meat.
Researched by Peter Jaret. Adapted from HEALTH, © 1995
Thin out the meat you do eat. Look for meat that carries a nutrition label so you can make an informed decision about what to buy. Currently, nutritional labeling for meat is voluntary, but about sixty percent of the packaged meat and poultry sold in stores does come with this valuable information on the package. Buy leaner cuts of meat, trim the fat, eat poultry without skin, eat smaller portions, and don’t fry.
Substitute low-fat or non-fat versions of fatty foods. This means using skim milk instead of whole milk, low-fat or non-fat yogurt, and choices from the array of low-fat or non-fat mayonnaises, salad dressings, and other foods. See the box on “Painless Ways to Cut Fat” for additional ideas.
Fat and Cholesterol Content: A Sampler of Common Foods
|For more counts, see the “Fat, Cholesterol, and Calorie Counter” at the end of the book.
Replace fatty foods with produce. Try snacking on apples, grapes, carrots, and other fruits and vegetables instead of fat-filled chips and sweets. This not only cuts down on fat, but boosts your intake of many valuable nutrients.
You can also hold down fat by watching for certain code words on packages and menus (see the “Giveaways to Fatty Foods” box nearby). Remember, though, that you can’t always rely on labels saying “low-fat,” “diet,” or “sugar-free” when eating out. Laboratory analysis of 10 frozen desserts billed as low-fat, low-calorie in New York establishments revealed that most packed as many calories as ice cream. One exception was Haagen-Dazs frozen vanilla yogurt, which had 88 calories and 0.2 grams of fat in a 5-ounce cup. To make matters worse, advertised calories are often based on a 4-ounce serving, while the “small” size you buy varies from 5 to 11.3 fluid ounces.
The only conclusive way to determine how much fat you’re really eating is to keep a daily diary of everything (yes, everything) you eat, then check labels to count fat grams and percent of Daily Values.
What Counts As A Serving
Breads, Cereals, Rice, and Pasta
1 slice of bread
1/2 cup of cooked rice or pasta
1/2 cup of cooked cereal
1 ounce of ready-to-eat cereal
1/2 cup of chopped raw or cooked vegetables
1 cup of leafy raw vegetables
1 piece of fruit or melon wedge
3/4 cup of juice
1/2 cup of canned fruit
1/4 cup of dried fruit
Milk, Yogurt, and Cheese
1 cup of milk or yogurt
1-1/2 to 2 ounces of cheese
Meat, Poultry, Fish, Dry Beans, Eggs, and Nuts
2-1/2 to 3 ounces of cooked lean meat, poultry, or fish
Count 1/2 cup of cooked beans, or 1 egg, or 2 tablespoons of peanut butter as equal to 1 ounce of lean meat (about 1/3 of a serving)
Source: FDA Consumer
Partly because so many of us eat more fat than we need, excess weight is relatively common in the U.S. Too many extra pounds increase your chances of developing high blood pressure and, therefore, of having a stroke. Being overweight is associated with the higher cholesterol levels that can lead to heart disease. And obesity is a factor in type II diabetes—the kind that usually develops in adulthood. (To learn your ideal weight, see “Setting a Healthy Goal.”)
How much you need to eat depends on your gender, age, and activity. Men need more than women, younger people need more than older adults, and active people need more than the inactive. The Daily Value information on food labels is based on a relatively modest 2,000-calorie diet unless otherwise specified.
When adding up your calories based on food labels, be careful about the definition of a serving. The FDA’s idea of a serving is surprisingly small and may not match yours. (Does your spaghetti dinner usually amount to half a cup?) See the nearby box “What Counts as a Serving” for the official numbers. It may be worth measuring what you actually eat for a few days to see how closely it mirrors the printed serving sizes.
If you are cutting back on fat, this will automatically help you cut calories. One gram of fat packs about 9 calories, more than double the 4 calories in a gram of protein or carbohydrates. A regular exercise program will also help. What you burn, as well as what you eat, affects how much weight actually stays on you. Finally, there’s the old stand-by:
Hold the sugar. Mom and your dentist were right—sugar is mostly empty calories that fill you up, leaving less room for food with other nutrients. And sticky sweets and soda can rot your teeth. So, when the FDA recommends getting 60 percent of our calories from carbohydrates, they are really talking about the complex carbohydrates in starch, not the simple ones in sugars.
Adding a teaspoon of sugar to your coffee or tea isn’t a problem for most of us. All table sweeteners combined contribute less than a fifth of our daily intake. The major sources of sugar to keep in mind include:
- Soft drinks—25%
- Packaged foods, dressings, and other—21%
- Table sugar, jams, syrups—18%
- Baked goods—13%
- Ice cream, dairy—10%
- Breakfast cereals—5%
The Sugar Association says that, when you add it up, more than half the sugar we eat comes from processed foods—another reason (along with sodium), to favor fresh products. When you do buy processed foods, watch the labels. Sugar can pop up in the oddest places—ketchup (11 percent sugar), salad dressing, frozen pizza, and nondairy creamer, for example. Don’t be fooled by sugar’s disguises on labels, either—it goes by 18 different names in various lists of ingredients (see nearby box.) And remember that the natural fructose in fruit does count towards your total sugar intake.
Sugary foods may seem like quick energy boosters, but the initial burst is followed by a slump. Complex carbohydrates work more slowly but are a better choice for longer-lasting energy.
The FDA recommends that we get 2,400 milligrams a day of sodium, about the amount in 1 teaspoon of salt. But by one estimate, men actually eat 4,000 milligrams, or 2 teaspoons per day, while women get 3,000 milligrams a day, or one-and-a-third teaspoons daily.
Reducing the sodium you take in can be tougher than you’d expect, because 75 percent of the sodium we eat is hidden in processed foods. Only 15 percent of most people’s sodium intake comes from the salt shaker; about 10 percent is found naturally in food. Sodium also is not necessarily where your taste buds would lead you to believe. McDonald’s french fries have less salt than any McDonald’s sandwich, biscuit, or Danish. Some salad dressings have 200 milligrams of sodium per tablespoon.
To get your sodium intake down, you’ll need to cut back on most brands of frozen dinners or pizza (Healthy Choice is one exception); processed meats like hot dogs or bacon; processed American-style cheese; canned or dried soup; salad dressings; and canned meats, beans, vegetables, and tomato sauce. Choose fresh rather than canned foods, and look for items labeled “less sodium,” “sodium-free,” or “light-in-sodium.” Check the “Nutrition Facts” label. Products that list less than five percent of the Daily Value on the Nutrition Facts label are considered low-sodium, while those that contain more than twenty percent are considered high-sodium.
What About Alcohol?
Recent studies suggesting health benefits from moderate drinking have caused a bit of a stir. Alcohol apparently raises levels of “good” HDL cholesterol (the type that helps keep arteries clear) and may help prevent blood clots, thus reducing the likelihood of heart disease. However, evidence of an actual protective effect is still considered inconclusive. For example, one large, long-term study revealed that men who had one or two drinks a week had a lower death rate than both heavy drinkers and those who did not drink at all, but experts say that this could be due to other factors not evaluated in the investigation. Also, some of the other studies showing reduced heart disease with moderate drinking did not measure complicating factors that could have affected the results, such as whether or not the people in the study smoked.
On the other hand, the harmful effects of heavy drinking are quite certain. People who have one to three drinks a day run a 60 percent higher risk of developing oral cancer than do nondrinkers. Heavy drinkers are also at higher risk for larynx and esophageal cancer. Given these facts, doctors continue to warn against anything more than moderate drinking, if you drink at all. Moderate drinking is one drink or less daily for women and two or less for men. One drink is a glass (5 ounces) of wine, a can (12 ounces) of beer, 1.5 ounces of liquor or spirits (80 proof).
Instead of seasoning food with salt, try cooking with herbs, spices, and lemon juice, to broaden your palate’s taste sensations. Try recipes in cookbooks or magazines that emphasize healthy (low-fat, low-calorie, low-sodium) meals. Stop cooking with salt, or add only half the amount specified in the recipe—chances are you won’t notice the difference. And move gradually to lower-sodium products and cooking, so your taste buds can adjust.
Restaurant food and fast food are also notoriously high in sodium. Healthful dining choices include grilled or roasted entrees and baked potatoes. Use of oil and vinegar instead of a salad dressing will also help reduce your sodium intake. Don’t be shy about requesting that the chef refrain from adding salt while preparing the food.
The reason for all the concern over sodium is its link with high blood pressure. In certain “sodium-sensitive” individuals, too much salt can cause a sustained increase in blood pressure, and since there’s no way of telling in advance whether you’re among the sensitive ones, cutting back on salt is the only completely safe course. If you do develop high blood pressure, your chance of heart disease goes up. Optimal blood pressure is less than 120/80; high is 140/90; and anything above optimal raises the risk of heart disease. About 4 out of 5 people aged 35 or older have blood pressure above optimal levels; and even if your pressure is low now, it’s likely to increase with age. On average, the first number in the blood pressure measurement goes up 15 points between the ages of 25 and 55. If everyone lowered salt intake by 1 teaspoon a day, the thinking goes, the average increase with age could be pared back to 6 points.
High blood pressure isn’t the only problem with too much sodium. Because it causes your body to lose calcium, it can raise your chances of developing osteoporosis, the brittle-bone disease of old age. Losing calcium is all right if you eat enough to compensate, but most of us don’t.
Getting more carbohydrates (the complex kind) means eating more bread, pasta, rice, and other grains as well as extra fruits and vegetables. The goal is to make carbohydrates 60 percent of your calories, compared with the 20 to 25 percent that most of us get today. Just as eating less fat and sodium can help cut the odds of heart disease and high blood pressure, eating more fiber-containing grains, fruits, and vegetables can help lower your chances of getting cancer and heart disease.
The facts about fiber. Fiber is found in fruits, vegetables, and grains, and you should get 25 grams of it per day. The food labels tell you how many grams of fiber a serving contains. However, because testing is not always accurate, some nutritional experts estimate that the amount on the label is often 5 to 25 percent higher than the actual content. What about unlabeled produce? The nearby box gives the numbers for some of our favorite fruits and vegetables. Juice counts as a serving of a fruit or vegetable, but won’t provide fiber. (Remember that only 100 percent pure juice counts—some products are mostly sweetened water.) Whole grains give you more fiber than refined products from which the fiber-containing husk is removed.
Fiber reduces your risk of the top two killers in this country—cancer and, in the case of soluble fiber, heart disease. Diets lacking in insoluble fiber have been linked to colon cancer. Diets high in fruit, vegetables, and fiber have been shown to reduce your chances of developing precancerous colon polyps. Try to get your fiber from food rather than supplements: Some benefits of a high fiber diet come from the food itself as well as the fiber.
Finding Fiber in the
|Fruits & Juices||Fiber (grams)|
|Apple (1) or Pear (1)||4|
|Apricots, dried (1/3 cup)||4|
|Blueberries, raw (1 cup)||4|
|Figs, dried (2)||4|
|Apple, without skin (1)||3|
|Banana (1) or Orange (1)||3|
|Cherries (1 cup) or Prunes, dried (5)||3|
|Strawberries (1 cup)||3|
|Grapes (1-1/2 cups) or Plums (2)||2|
|Nectarine (1) or Peach (1)||2|
|Cantaloupe (1 cup)||1|
|Orange juice (1 cup)||1|
|Watermelon (2 cups)||1|
|(Serving size: 1/2 cup, cooked)|
|Potato, baked, with skin (1)||4|
|Sweet potato, baked, with skin (1)||4|
|Asparagus or Broccoli||2|
|Cabbage (1) or Spinach (1)||2|
|Carrots, raw, or Corn kernels||2|
|Cauliflower or Green beans||2|
|Lettuce, romaine (1-1/2 cups)||2|
|Celery, raw, or Green pepper, raw||1|
|Lettuce, iceberg (1-1/2 cups)||1|
|Mushrooms, raw (1 cup)||1|
|Tomato, fresh, raw (1/2)||1|
|Cucumber, sliced, raw||0|
|Copyright 1994, CSPI. Reprinted from Nutrition Action Healthletter (1875 Connecticut Ave., N.W., Suite 300, Washington, D.C. 20009-5728. $24.00 for 10 issues).|
Even with fiber, it is possible to get too much of a good thing. Fiber scoops up minerals such as calcium, iron, and zinc on its way out of the gastrointestinal tract, making it potentially unhealthy for people at risk of osteoporosis and iron deficiency. Additionally, eating too much fiber without drinking enough liquid can clog your intestines.
Fiber added to food, especially breads, is sometimes really cellulose, an altered substance not like whole foods. Cellulose is rarely listed on the label, but the presence of added soy fiber or vegetable fiber should arouse suspicion. Cellulose may fight constipation but it’s not as effective as an equal amount of wheat bran. To avoid cellulose, stick to whole wheat bread.
Added benefits from fruits and vegetables. In addition to boosting your fiber and carbohydrate intake, increasing the fruits and vegetables in your diet may possibly lower your risk of lung, prostate, bladder, esophageal, and stomach cancers—or so some researchers believe. Choose fresh fruits and vegetables, if possible, to avoid the sugar and salt that may lurk in frozen and canned products. If you can’t find fresh, look for products without—or with little—added sugar, heavy syrup, sweetened fruit juice, or sodium. Aim for a variety of fruits and vegetables, not just the same few all the time. That will help ensure that you get the nutrients you need—you may be surprised by some of the intriguing new flavors you discover.
You can probably get by with less of this nutrient. The average American eats twice the amount needed. For most of us, there’s no danger in eating too much protein itself—but a problem arises when it crowds out other foods with nutrients we need. People with diabetes are an exception to this rule—they should not exceed the recommended value for protein (50 grams per day). Pregnant women and nursing mothers need more protein—as much as 60 and 65 grams per day, respectively.
If you’re concerned about the fat in your diet, you might want to consider getting more of your protein from vegetable sources such as beans and nuts, rather than fattier meats, eggs, and dairy products.
Many of the nutrition stories you see in the media are based on research that is, at best, inconclusive. The best of these stories contain important ideas for which evidence is accumulating, but for which there is not yet absolute proof. Some of these theories will eventually be confirmed; others will quietly disappear. In judging them, it’s important to remember that even in science, “proof” is a relative term. It simply means that many carefully planned studies have supported the idea. Theories that are promising rather than proven generally have fewer studies to back them up, or have some studies that contradict others. (See the box on “When to Believe a Media Report,” for details.) Here are some of today’s theories most likely to become tomorrow’s facts.
As eminent an authority as the chairman of Harvard University’s nutrition department says Yes, and he’s not alone. The Harvard School of Public Health, the European office of the World Health Organization, and Oldways Preservation & Exchange Trust, a nutrition think tank, also endorse the Mediterranean Diet as a tasty, nutritionally superior alternative to the USDA pyramid.
Which Pyramid For You?
|Some experts have gone a step beyond the government and endorsed a nutrition plan called the “Mediterranean Diet,” which comes complete with its own food pyramid. This plan shifts the emphasis further away from meat, focusing on fish, beans, nuts, cheese, and yogurt as alternative sources of protein. Small amounts of wine, considered good for the heart, are optional. Regular exercise is mandatory.
Adapted from Mediterranean Diet Pyramid. Oldways Preservation and Exchange Trust
The Mediterranean Diet is similar to—but more detailed than—the pyramid. It focuses on lowering animal fat, rather than all fat. It recommends little or no red meat (a few times a month), compared with the 2 to 3 servings a day from the catch-all “meat group” compiled by the USDA. It also puts vegetable protein (such as that in beans and nuts) into a separate category from meat. These differences yield a diet with less saturated fat than the government pyramid (7 to 8 percent of calories), but more fat overall (35 percent of calories).
In the Mediterranean Diet, vegetable fat in the form of olive oil is actually recommended in certain quantities. The reason: Olive oil and other monounsaturated fats increase “good,” artery-clearing HDL cholesterol, but not “bad,” artery-clogging LDL cholesterol. Remember, however, that if you’re trying to lose weight, you still need to limit your intake of all fats, including olive oil. (For more on oils, see “What to Do about Fat.”)
On the other hand, the Mediterranean Diet includes no more than 16 ounces of red meat per month. Indeed, Harvard’s chairman of nutrition says the optimum amount of red meat could well be zero, as (a) we can get its nutritional value elsewhere, (b) it is high in fat and cholesterol, which are linked to heart disease, and (c) some data link red meat to colon and prostate cancer.
Both the Mediterranean Diet program and the federal Dietary Guidelines for Americans recommend regular physical activity. The Mediterranean Diet program also includes the optional, daily moderate consumption of wine. The federal Dietary Guidelines recommend drinking moderately, if at all.
Interest in the Mediterranean Diet stems from observations more than 30 years ago that people on the Greek island of Crete got 40 percent of their calories from fat but were only about one twentieth as likely to die of heart disease as Americans. A key difference was that much of the fat came from olive oil rather than meat. Despite their high-fat diet, the people of Crete actually took in less cholesterol-raising saturated fat than did Americans.
Today, it’s generally agreed that the Mediterranean Diet won’t hurt you, and some nutritional authorities say it’s healthier than the USDA pyramid approach. It can be tasty, too. Spain, southern Italy, Greece, and the Provençal region of France, the historical havens of Mediterranean cooking, are well known for their culinary delights.
Tip-Offs of Nutritional Hype
Much of what we see and hear about nutrition is at best exaggerated, and at worst deliberately misleading. Here are a few clues that what you’re hearing is hype.
Hype is most common in areas where:
Be suspicious if:
These cancers tend to be more common among people eating high-fat diets. Women in Japan eating the country’s traditional low-fat diet are less likely to develop breast cancer than women in the U.S. Even more telling, the granddaughters and great-granddaughters of Japanese women who moved to the U.S. and switched their families to a high-fat diet are almost as likely to develop breast cancer as anyone else.
Such evidence does not prove that a high-fat diet causes these types of cancer, however, because many other factors could be involved. For example, it could be that people who eat lots of fat simply don’t get enough of the fiber-containing fruits and vegetables that are known to reduce the risk of cancer. Moreover, most of the studies in this area have measured the incidence of cancer and the fat in diet, but not factors, such as family history of cancer. As they say, further studies are required.
Chronic alcohol use is a risk factor for throat and liver cancer, and possibly for breast and colon cancer. Scientists have not yet figured out the exact role of alcohol in the development of cancer, or what amount of alcohol raises the risk. If you consume alcohol, experts recommend doing so in moderation.
Several large, long-term studies have found that colon cancer—or the colon polyps that often precede cancer—is much more common among people who eat red meat frequently. And a similar, long-term study has found that prostate cancer is more than twice as common in the men who eat the greatest amounts of red meat. This research doesn’t prove that red meat is the cause of colon and prostate cancer. After all, most meat-eaters don’t get either disease. Still, it appears that cutting down on red meat improves your odds of escaping those diseases.
Some research says Yes; but the practical significance of this—if any—is still unknown. For details, see “Cut Back on These Foods to Cut Your Cancer Risk.”
Maybe. If nothing else, switching from animal sources (red meat, poultry, fish, and dairy products) to plant sources (beans, grains, and nuts) will lower your fat and cholesterol intake. Americans get twice the protein they need as it is, and two-thirds of that comes from animal sources. Switching even half of your meat intake to plant protein can cut your cholesterol levels—by 13 percent in one study. That’s important, because if your cholesterol is more than 200, every 1 percent drop could diminish your heart disease risk by 2 percent. One caution: most research in this area uses soy protein. Wheat, rice, or other plant foods might not have the same effect. Also, the best results have been found in Italy and Switzerland, where other factors may be at work.
Stomach cancer is rare in the U.S., but deadly when it strikes—and some evidence seems to show that avoiding very salty food can help reduce risk. Salt intake is higher among people with stomach cancer; and some research suggests that salt-cured, pickled, or nitrite-preserved foods may be responsible for the higher rates of stomach and esophageal cancer found in countries where these foods are common. The risk in the U.S. diet, however, appears to be small.
When To Believe A Media Report
How many times have you given up trying to figure out what’s healthy because the experts can’t make up their minds? A few months—or years—of stuffing down oatmeal or oat-bran muffins in what turned out to be a vain hope of lowering cholesterol could turn anybody sour on science.
The problem is not that researchers or the media are lying, or that they really don’t know anything. It’s just that a single, limited study is often ballyhooed as if it were the final answer. Unfortunately, the standards of good science require many types of studies to agree before something can be considered a certainty. Much of the research so prominently reported in the media is just one step along the way, not conclusive evidence. Unfortunately, that part of the news doesn’t make the headlines.
Here are some questions to ask before believing the next “bulletin” from the laboratory:
Is it an animal study? Ideas are usually tried out on animals before they are tested in people, both to ensure safety and to find out if the concept is worth the extra cost of a human study. Evidence from animal studies is important. But what happens in a lab rat, for example, may have no relevance to you and me. Findings from animal studies are clues, not facts.
Is it a test-tube experiment? Like results from an animal study, the findings from test-tube (“in vitro”) research may have no bearing on what happens to people. Like animal studies, test-tube work is a way of testing the safety and validity of an idea before trying it in people.
Is it a population study? Population studies do involve people, but they too have limitations. Here’s how population studies usually are conducted: If an investigator thinks that factor A (for example, fat in the diet) plays a role in development of disease B (breast cancer), he will count the number of cases in a large group and measure the amount of fat consumed by women who did, and did not, develop the disease. If those who did not develop breast cancer ate much less fat than those who did, this finding lends support to the scientist’s theory. The flaw in most such studies is that they fail to account for the many other factors that could be at work, such as heredity, smoking, and use of birth-control pills. Ultimately, this type of finding is a clue, not a fact.
Is it a real-time study? This type of research, called a prospective study, assembles a group of people with specific characteristics, measures certain things about them, then tracks changes in them over a period of time. A retrospective study, on the other hand, involves searching through records for characteristics and changes after the fact. Because accuracy will be greater if you know in advance which change to track, a prospective study is viewed as more reliable than a retrospective one that relies on records made for a totally different purpose. However, retrospective studies often serve to point the direction a more definitive prospective study should take.
Did it use a placebo? A placebo, or dummy pill, contains no active ingredient, yet can make some people get better if they think it might be real. This is the famous placebo effect, and it helps scientists sort out how much of an effect is really caused by a medicine and how much is in people’s minds. Placebo-control, as this technique is called, is one sign of a reliable study. Unfortunately, it’s not practical in many studies, where a fake could be detected or the test involves withholding a substance rather than giving one. And if the real pill turns out to be a life-saver, ethics demand that the study be halted.
How many people were studied? The fewer the people in a study, the more likely that the findings are due to special circumstances or chance. Smaller studies are performed before larger ones to ensure the safety of the therapy being tested and to find out whether the cost of a large study is justified. This does not mean that 10-person studies are worthless—just that they are not definitive.
How long did the study go on? All other factors being equal, longer studies are better than short ones. This is because it may take a long time for dietary changes or drugs to make a difference. Cancer and heart disease, for example, develop over a long period of time, and, researchers often don’t know how long it will take for a change in diet or a drug to have its effect. On the other hand, a change in, say, blood pressure that’s seen after a few months could be just temporary. The only way to know for sure is to follow people for a longer period of time.
Did the scientists allow for other possibilities? Many factors besides diet can influence development of a problem like heart disease or cancer, including smoking, exercise, heredity, and age. If there is a placebo group in the study, one way to account for these factors is to make sure that the placebo and treatment groups both include, for example, the same percentage of smokers. If one group then suffers an increase in disease, it can’t be blamed on smoking.
Is this a new “discovery,” or do other studies back it up? No matter how carefully the research is done, scientists almost never regard a single study as definitive proof. It’s the whole body of evidence that counts. One study could be a fluke—its findings could be due to a mistake, or to some unrecognized characteristic of the people evaluated. Usually, many studies—and at least a few different types of studies—must support a point before researchers view the finding as definitive.
Although we learn more about nutrition every year, there are still areas where the experts still don’t have an answer. Sometimes this is due to conflicting research, sometimes to conflicts in interpretation. Here’s a quick look at three of today’s biggest controversies.
Experts have become increasingly convinced that they are. Originally established to prevent acute deficiency diseases like scurvy and rickets, the RDAs for vitamins and minerals are currently pegged at the level deemed “adequate” for most healthy people. They are not intended to reflect the ideal amount required to maintain health at its peak.
The National Academy of Sciences, a private, non-profit organization that provides health policy advice to government agencies, has been giving the old RDAs a major overhaul. No longer focusing on the use of nutrients to prevent vitamin deficiencies, the task force is reviewing the scientific literature to determine the best way to use vitamins, minerals, and plant extracts to promote optimal health and prevent chronic disease. The new guidelines they’re developing are called DRIs or “Dietary Reference Intakes.
The DRIs will not only recommend what the daily dose of a nutrient should be, they’ll also set upper limits beyond which a toxic reaction may set in. The National Academy of Sciences is midway through the revamping process. Once all the nutrients have been reviewed, the Food and Drug Administration will incorporate the new DRIs into food labeling and recalculate Daily Values.
Some experts insist that response to sodium varies from one person to the next. According to some estimates, extra sodium increases blood pressure in about 5 to 15 percent of the population, and in 25 to 60 percent of those with high blood pressure. Sensitivity to sodium increases with age. Other authorities believe that sodium does affect blood pressure in most of us, though more in some than others.
To add to the confusion, experts disagree over the interpretation of what information we have available. Some say that research has not conclusively demonstrated a direct, strong link between sodium and high blood pressure. They suggest that large, sustained reductions in sodium are needed to affect blood pressure, or that not everyone’s blood pressure benefits from cutting sodium intake. Others, looking at the same studies, say they confirm the link.
If there is this much controversy, why does the government recommend limiting sodium? For starters, no one really knows how many people are sensitive to sodium’s blood pressure-elevating effects, nor is there any way of telling who’s sensitive and who’s not. Since almost all of us eat far more than required, cutting back won’t hurt, and could help reduce the risk of heart disease.
Hotly disputed research suggests that the omega-3 fatty acids in fish lower cholesterol levels, perhaps by reducing the amount of cholesterol manufactured by the body.
Less controversial is fish oil’s ability to increase the time it takes blood to clot. This may reduce the chance of a clot, blocking an artery and causing a heart attack, but it can also increase your risk of bleeding, bruising, and anemia. Accordingly, moderate amounts of fish oil are considered healthy, while the large quantities found in fish oil capsules should never be taken without medical supervision. Though the capsules have been shown to reduce triglyceride (blood fat) levels and are prescribed for that reason, they have not been shown to reduce “bad” LDL cholesterol.
What To Look For On Labels
The new food labels make it easy to see whether a product is “nutritionally correct.” The most important things to look for are the ones most prominently displayed: fat, saturated fat, cholesterol, sodium, calories, and fiber. (Remember though, that the FDA allows manufacturers a 20 percent margin of error in the labeled amounts.)
If you’re watching specific ingredients, you’ll find them listed in the order of their amount. An ingredient not among the first three probably isn’t included in significant proportions.
Be careful to check serving sizes, too. If cereal A lists its serving size as half a cup and cereal B says it’s two-thirds of a cup, then you can’t do a head-to-head comparison of nutrient content without some math. Also compare the serving size to what you really eat. If you pour yourself a cup of cereal every morning, and the label gives calories for half-a-cup, remember to double it, however painful that is. Fortunately, serving sizes have been somewhat standardized on the new labels.
Look for health claims because in order to carry them, the food must meet stringent requirements for fat, saturated fat, cholesterol, and sodium, providing no more than 20 percent of the Daily Value for each. For example, even though whole milk is high in calcium, its labeling can’t make a claim about preventing osteoporosis, because it’s too high in fat.
A number of common advertising buzzwords now have strict definitions. Here’s what the FDA assures us they mean:
Fiber and soluble fiber. To carry a claim that it contains fiber that reduces heart disease, a product must be high in soluble fiber (at least 0.6 grams per serving). Labels don’t have to list soluble fiber, so this is one way you can find out if it’s there. Manufacturers can only make health claims for foods containing naturally occurring fiber.
“Free,” “without,” “no,” “zero.” To use these words on food labels in connection with fat, saturated fat, cholesterol, sodium, sugars, and calories, the food must contain zero or a trivial amount of each. For example, fat-free means a serving contains less than half a gram of fat, which is insignificant even if you eat several servings. The FDA can’t require zero because fat can’t be measured below a certain level.
“Lean.” On meat, poultry, and seafood, this word means less than 10 grams of fat, less than 4 grams of saturated fat, and less than 95 milligrams of cholesterol per serving and per 100 grams.
“Extra lean.” Meat, poultry, and seafood bearing this phrase must contain less than 5 grams of fat, less than 2 grams of saturated fat, and less than 95 milligrams of cholesterol per serving and per 100 grams.
“95 percent fat free.” This means that the food contains 5 grams or less of fat per 100 grams of the food.
“High,” “rich in,” “excellent source of.” Foods using these words in connection with any nutrient must contain at least 20% of the recommended Daily Value for that nutrient per serving.
“Good source of. “ This means one serving contains 10 to 19 percent of the Daily Value for that nutrient.
“Light,” “lite.” These favorites can mean one of two things: (1) a nutritionally altered product containing one-third fewer calories or half the fat of the “real” food (eg, mayonnaise); or (2) the sodium content of a low-calorie, low-fat food has been reduced by 50 percent. These terms can still be used to describe color and texture if it’s made clear what “light” refers to.
“Low cholesterol.” This means the product contains no more than 20 milligrams of cholesterol per serving, or no more than 2 grams of saturated fat per serving. No matter how low the cholesterol, a product can’t make a cholesterol claim if there’s more than 2 grams of saturated fat in a serving.
Nutrition is a vast area, often vulnerable to oversimplification and misinterpretation. And, once enshrined by the media, the resulting half-truths and outright errors take on a life of their own. Here is the truth about some of the misconceptions still making the rounds today.
Eating more protein, plant or animal, does pull more calcium from the body, but not as much as once was thought. Additionally, your body may adapt and stop losing calcium at some point. A 1980 study found less osteoporosis among vegetarians, but more recent studies have failed to confirm that.
There is no direct evidence of a problem here. Kidney disease is rare in this country despite our high protein intake. Only diabetics need to limit protein to the level specified in the RDAs (50 grams per day).
There is little evidence that animal protein increases the risk of cancer. Researchers, including those at Dana-Farber Cancer Institute in Boston, have been unable to verify a strong link between protein and breast, colon, or kidney cancer. Researchers at Cornell University did find that feeding rats more protein, especially animal protein, made them more likely to develop liver cancer when given a substance known to cause the disease. But this could be unique to the cancer-causing substance used in the study, and to liver cancer, which is rare in the U.S. despite our high-protein diet. Most experts agree that this finding does not justify changing your diet.
There is a kernel of truth to oat bran’s cholesterol-lowering powers. Early studies did find that oatmeal or foods containing oat bran could lower cholesterol. In 1990, however, researchers failed to verify these findings in a study done on a group of young women. Analysis of data from several previous studies then revealed that oat bran lowers cholesterol by so small a percentage (5 percent or less) that its effects are insignificant for most of us.
Cutting your intake of saturated fat and cholesterol is clearly a more effective way of reducing your risk of heart disease. This doesn’t mean it’s bad to eat oat bran or oatmeal—grains provide fiber and should form the basis of our diet. It’s just that oats won’t have a major effect on your cholesterol.
It used to be conventional wisdom that dieting meant cutting down on starch—bread, potatoes, pasta, and rice. Now, for most people these foods are considered the basis of any good diet, including weight-loss programs. Starch has the same number of calories as protein—4 per gram—and many fewer than fat, which has 9 calories per gram.
Most starchy foods are nearly fat-free, as long as you forgo toppings like sour cream on potatoes or Alfredo sauce on pasta. The body uses more energy processing starch than it needs to burn fat; so starch not only gives you less fat and fewer calories than fatty foods, but also makes the body burn more calories—a good combination. In some overweight people with a problem called “insulin resistance,” excess carbohydrates do tend to add extra pounds. But for most of us, they remain the best source of needed energy.
Following the current guidelines for healthy nutrition doesn’t doom you to life with a calculator. The theoretical target is 60 percent carbohydrates, 30 percent fat, and 10 percent protein, but in daily life that simply means going heavier on fruits, vegetables, and grains, lighter on meat and dairy, and very light on oils, salad dressings, mayonnaise, and sweets.
A balanced diet means just that—balance. You don’t have to make sure every food, or even every meal, is exactly 30 percent fat—just balance a rich restaurant meal with a light vegetable-and-rice dinner the next day. Healthy eating does not have to mean giving up foods you like, feeling guilty when you have a big meal, or viewing every decision about what to eat as inherently “good” or “bad”—all or nothing. You can eat ice cream or chocolate cake—just watch how much, and how often, you do it. Here’s the bottom line on today’s balanced diet and how it differs from what most of us are used to.
All the experts agree: Eat less meat. How much less? For most of us there’s so much room for improvement that it really doesn’t matter. Though statistics show that we are eating less red meat, most of us have switched to white meat rather than grains, fruits, and vegetables. We’re also still eating too much fat—33 percent of calories from fat, instead of the recommended 30 percent, and 11 percent from saturated fat, rather than the recommended 10 percent, according to a government report.
These foods are out of favor for the same reason as meat: many are high in fat and cholesterol, and most of us eat too much of them. You don’t have to cut back severely, however. Switching to low-fat or skim versions will go a long way towards balancing your diet with little pain. Moderation is the key. Avoid having eggs and bacon every day, but don’t hesitate to have an omelet on the weekend.
Low in fat, full of fiber and vitamins, these are the foods we don’t get nearly enough of. Even if your fat intake is low, you probably need more rice, pasta, whole-grain bread, fruits, and vegetables.
With so much evidence that a diet low in fat and high in fiber, fruits, and vegetables can help fend off the top two killers of Americans—heart disease and cancer—making a few sacrifices in your diet seems well worth the effort. Surprisingly, those sacrifices are much smaller and easier than you’d expect.
As the title of Dr. Dean Ornish’s popular book announces, you really can “eat more, weigh less.” It’s all in what you eat. Cutting way back on high-calorie fat leaves room in your diet for more food than before—with no increase in total calories. And trimming the fat shouldn’t leave you hungry, either. Your body is designed to signal you when carbohydrates drop, but not when fat intake goes down. On an “eat more, weigh less” diet, you’ll get plenty of carbohydrates to keep you feeling full.
Big benefits can come from minor changes. One small study at the University of Washington in Seattle showed that switching to skim milk from whole milk for 6 weeks reduced total cholesterol by 7 percent and “bad” (LDL) cholesterol by 11 percent without diminishing “good” HDL cholesterol. In a study at a Harvard University-affiliated hospital, women lost an average of 5 percent of their weight by making seven simple changes, including substituting skim for whole milk, non-fat frozen yogurt for ice cream, and fruit spread for margarine or butter.
Take advantage of foods reformulated as low-fat, low-calorie, and low-cholesterol. They can be a boon if you absolutely cannot pass up certain favorite dishes. They can also help you get past the mental block that healthy eating has to mean cutting out what you like. Just remember not to view the “fat-free” label as a license to eat extra amounts, or “reward” yourself for foregoing one fatty food by gobbling up another.
Keep fruits, vegetables, and grains ready to eat in the house. Don’t bring home as much meat and fatty food from the supermarket. If it’s not in the refrigerator when you get home for the day, you probably won’t run back out to buy it.
Above all, be patient with yourself. An overnight make-over isn’t all that important, as long as you keep making progress. If you eat a 10 ounce piece of meat for dinner every night, try cutting back to 8 ounces, then 6 ounces, gradually filling in with pasta, rice, vegetables, and fruit. Don’t let yourself go hungry. If it takes you a few years to get down to the USDA’s recommended 3 ounce serving, that’s better than never making it at all.