Building a Better Pyramid
For: Ask the Experts, July 2002
The pyramids of Egypt have stood the test of time, but the U.S. Department of Agriculture (USDA) Food Pyramid, now in wide use and taught to schoolchildren all over this land, is under attack. According to Dr. Walter Willett of Harvard University, this pyramid does more harm than good, is seriously outdated, was based on shaky science in the first place, and reflects the needs of the meat and dairy industries, not those of the American consumer. In his excellent new book, Eat, Drink, and Be Healthy, Dr. Willett proposes a new "Healthy Eating Pyramid" of his own. Both pyramids are shown below.
What's wrong with the USDA pyramid?
According to Dr. Willett:
• The USDA pyramid lumps all fats together at the top, in the "eat sparingly" category. But, in fact, highly saturated fats (generally from animals) such as butter or lard are different from polyunsaturated and monounsaturated fats, found chiefly in vegetable oils. These unsaturated fats are heart-healthy. Thus, in the Willett pyramid, plant oils have moved to the base—that is, one of the foundations of the diet.
• The USDA pyramid does not distinguish between high-fiber and low-fiber carbohydrates. In the Willett pyramid whole grains have replaced the USDA's "bread, cereal, rice, and pasta" group at the base. Meanwhile, refined grains (such as white bread and white rice), as well as potatoes, have joined sweets in the "use sparingly" triangle at the top of Willett's pyramid. These foods cause spikes in blood sugar and, Dr. Willett believes, increase the risk of diabetes over time.
• Confusingly, the USDA pyramid combines various protein sources (meat, poultry, fish, beans, eggs, and nuts) in one huge category. Dr. Willett relocates nuts along with legumes (beans) in the middle of his pyramid, and banishes red meat to the attic, along with butter, potatoes, refined grains, and sweets.
• He says that the USDA overemphasizes dairy. So his pyra--mid hoists dairy northward, recommending only one or two servings daily—or a calcium supplement instead.
What's wrong (and right) with both pyramids?
Dietary advice has become more sophisticated and complicated
in recent decades. A simple diagram like a pyramid can be useful in conveying
only a few general principles. The nitty-gritty has to come from somewhere
else.
Here's what we think:
• Indeed, the USDA pyramid should distinguish among various kinds of fat. But putting fats and oils at the top of the pyramid, under "use sparingly," is still the right way to go. All fats are calorie-dense and should be consumed sparingly. Fats should supply less than 30% of your daily calories. You shouldn't simply add tablespoonsful of so-called "healthy" oils to your daily diet. A tablespoon of oil is all fat and has 120 calories.
It's confusing to see vegetable oils sitting next to whole grains at the base of the Willett pyramid. This puts a heavier emphasis on oils than on vegetables. Should we put olive oil on our breakfast cereal?
• Dr. Willett is not the first to criticize the USDA pyramid for lumping meat, poultry, fish, dried beans, eggs, and nuts together as protein sources. Beans belong with vegetables. Nuts are a prime source of unsaturated fat, as well as protein. But neither pyramid makes a distinction between fatty and lean protein, or fatty and lean meats. A chicken leg with its skin (and underlying fat) is just as fatty, ounce for ounce, as a steak.
If you make fruits, vegetables, and whole grains the basis of your diet, there's room for small servings of lean meat. Lean cuts of beef (such as round) are okay if trimmed of visible fat, and eaten in small portions (3 to 4 ounces). The same rules apply to poultry, too: skinless breast meat trimmed of fat is okay, but you should still keep serving sizes small.
•Whole grains are more healthful than refined grains (such as white flour). The USDA should certainly have drawn this distinction, rather than pretending that white bread is as good for you as whole wheat. But there is nothing wrong with potatoes—a good nonfat source of vitamins, minerals, and fiber—or with pasta, that staple of one of the much-praised Mediterranean diets. Obviously potatoes and pasta should be consumed in moderation, as part of a balanced, varied diet. Potatoes should not be the only vegetable you eat.
• Neither pyramid admits a difference between full-fat and nonfat or low-fat dairy products. Whole milk and products made from it are high in saturated fat, cholesterol, and calories; nonfat and low-fat dairy products are not, but they supply the same important vitamins and minerals. Calcium pills should be taken in addition to dairy products, not instead of them. Nonfat or low-fat dairy products can help prevent and control hypertension; 2 or 3 servings daily are recommended in the DASH diet for hyper-tension.
• The Willett pyramid recommends a daily multivitamin pill "for most people," as well as alcohol in moderation ("unless contra-indicated"). These are good ideas; we also recommend a multivitamin/mineral for most people. It's true that alcohol in moderation helps protect the heart, but this does not mean that nondrinkers should necessarily start drinking for health reasons. Drinking may raise the risk of certain cancers—and does increase the risk of falls, crashes, and other injuries. And some drinkers do become alcoholics.
• Finally, at the base of the Willett pyramid are "daily exercise" and "weight control." This is excellent advice.
Final thoughts
Both pyramids are flawed. But one point is beyond dispute:
a wide variety of fruits, vegetables, and whole grains are the foundation
of a healthy diet. You should include nonfat or low-fat dairy, and at
least two servings of fish a week. Eat lean meats only, and in small amounts
(though a vegetarian diet, with no meat, is also healthy). Choose fats
and oils carefully—canola, olive, and other vegetable oils are good
choices for cooking and salads. Include walnuts, almonds, and other unsalted
nuts in your diet. Eat sweets and refined grain products in moderation.
You don't have to give up everything you like.
UC Berkeley Wellness Letter, December 2001
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