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The USDA pyramid includes six to 11 servings of bread, cereal, rice and pasta; two to four servings of fruit; three to five servings of vegetables; two to three servings of milk, yogurt and cheese; and two to three servings of meat, poultry, fish, dry beans, eggs and nuts. At the top of the pyramid are fats, oils and sweets, which should be used sparingly.

"The pyramid definitely needs some rebuilding," McCullough says.

However, consult your doctor before you change your diet to take into account any medical conditions you may have.

The"Fat" Facts

The Harvard guidelines make a distinction between red and white meats. Americans tend to eat too much red meat, which is a high-calorie, high-fat food, instead of leaner proteins such as chicken, turkey and fish.

Also, the USDA pyramid doesn't address healthy fats that can be found in vegetable oils such as olive and canola and nuts. Healthy fats can raise good cholesterol in the blood stream when they replace less healthy choices.

The government's guidelines also do not consider hidden trans fatty acids, which are created by partially hydrogenated vegetable oil and can be in everything from cookies to crackers. Trans fats often show up on nutrition labels as "partially hydrogenated vegetable oil". Scientists are researching the links between trans fats and health.

The AHEI takes trans fats into consideration when accessing overall eating habits and health risks. The Journal of the American Dietetic Association found that Americans should eat only 5 grams of trans fat a day, or 3 percent of total daily calories.

Fat plays an important role in health, so some is necessary, but all fats have more calories than protein or carbohydrates. Too much of some types of fat can lead to high cholesterol, a risk factor for heart disease. They also may increase cancer risk.

But not all fats are created equal. Fats and oils are made up of basic units called fatty acids. Saturated fatty acids are found mostly in animal sources such as meat and poultry, whole or reduced-fat milk, and butter. Some vegetable oils such as coconut, palm kernel oil and palm oil are saturated. Saturated fats raise blood cholesterol levels.

Healthy fats such as polyunsaturated fatty acids are found mainly in vegetable oils such as safflower, sunflower, corn, flaxseed and canola oils, as well as seafood. These are vital for cell structure and for making hormones. Polyunsaturated fats lower blood cholesterol levels.

Cholesterol

There is a difference between blood cholesterol and dietary cholesterol. Dietary cholesterol is found in food of animal origin such as egg yolks, meats and full-fat dairy products such as whole milk and cheese. Blood cholesterol is made naturally in the body and is absorbed from dietary cholesterol. It is used to make the essential hormones estrogen, testosterone and cortisol, as well as bile, which is necessary for digestion.

But if the level of cholesterol in the blood is too high, cholesterol and other fats can enter artery walls. Because blood cholesterol is waxy and cannot dissolve in water, it is carried through the blood in packages called lipoproteins. HDL gathers up excess cholesterol in the blood and carries it to the liver, which then excretes it. HDL also may help remove some cholesterol from artery walls. Too much LDL cholesterol (the "bad" cholesterol) can increase the risk of heart disease as it builds up on artery walls. The type of fats and oils we eat can help to control LDL levels.

The "Carb" Truth

The USDA food pyramid does not differentiate between the types of carbohydrates found in breads and pastas. Some are healthier than others, McCullough says. Foods with whole grains are better for cardiovascular health than refined carbohydrates found in overly processed breads, for example.

The quantity of "carbs" Americans consume also is a problem, McCullough says. Americans tend to eat too much nutrient-poor French fries and white bread, leading to high blood sugar and an increased risk for conditions such as type 2 diabetes. Fruits, vegetables and whole grains are better healthy choices for carbohydrates that provide energy but they also equally raise blood sugar.

External Resources: National Institute of Diabetes and Digestive and Kidney Diseases The American Dietetic Association American Heart Association Harvard School of Public Health-The Nutrition Source Centers for Disease Control and Prevention Produce for Better Health Foundation Food Surveys Research Group (US Department of Agriculture) Dietary Guidelines for Americans (USDA) USDA's Food Guide Pyramid for Young Children Nutrition.gov USDA's Food Guide Pyramid

This article was published on 2003-01-17
This article was reviewed on 2003-02-03