Nutrition

Can You Trust the Pyramid?

The Food Guide Pyramid - the USDA's visual nutrition guide, found everywhere from gradeschool textbooks to cereal boxes - is familiar to most Americans. Its recommendations for daily servings in the basic food groups are clear, concise, and easy to understand.

But recent books advocating low carbohydrate intake challenge the Pyramid's advice for healthy eating. Are carbohydrate-modified diets better for weight loss and blood glucose control? What about the long-term effects?

Carbohydrates include foods that turn to glucose during digestion - sweets, starches, fruits and milk. In the past 20 years, we've looked to these generally high- carbohydrate, "low-fat" foods primarily to reduce the risk of heart disease. Physicians and dietitians have recommended eating less animal protein and fat to reduce weight, blood fats, and blood cholesterol in order to reduce the risk of heart disease.

With the advent of "fat-free" foods, we gradually erred on the side of foods with too many carbohydrates, like pasta, bread, rice, corn, and peas. Weight gain in the United States has steadily increased. More than half of all adults are overweight, and sugar consumption also has steadily increased. The weight gain is certainly a contributing factor to diabetes, the incidence of which is steadily rising.

The authors of several recent diet books, including The Zone by Barry Sears and Sugar Busters! by H. Leighton Steward, contend that excess carbohydrates in the diet may contribute not only to weight gain, but to elevated blood glucose, triglyceride, and insulin levels. Triglycerides indicate the blood's fat content. When the body becomes resistant to its own insulin secretion from the pancreas, usually due to weight gain, the resulting excess insulin may increase plaque build-up in the blood vessels and increase the risk of diabetes or make existing diabetes more difficult to control.

The Zone and Sugar Busters! advocate lower carbohydrate intake. The Food Guide Pyramid recommends about 50 percent of calories from carbohydrates, about 20 percent from protein, and 30 percent from fat. The Zone recommends a 40/30/30 breakdown, respectively.

Certainly, following a diet such as The Zone for a brief time can yield weight loss and improved blood glucose levels, but there may be some caution for long-term use if renal or kidney problems exist or if a risk for osteoporosis exists. Excess protein (meat, fish, poultry, cheese, egg, milk) intake can worsen these conditions by putting more stress on the kidneys or causing more calcium to be excreted in the urine. Also, if an individual eats more fatty cuts of protein, excess fat intake can contribute to elevated cholesterol levels and weight gain.

The Sugar Busters! recommendation of virtually eliminating white foods - potatoes, white rice, corn,  bread from refined flour - as well as beets and carrots, may be rather extreme, and improvements can be achieved without such drastic measures.

Following the Food Guide Pyramid and the recommended size portions, one can still lose weight and control blood glucose, triglyceride, and insulin levels.

The problem is that most of us have lost all sense of what constitutes a portion size. It's not the "whole plate." For example, in the starch (cereal/grain or starchy vegetable, e.g. potatoes, peas, corn) category, a serving size is about 1/2 cup or one slice of bread. The range of recommended servings per day is 6 to 11. Six servings is adequate for a weight-conscious female.

But most people eat far more. Reducing portion sizes can produce some weight loss and control blood glucose, especially if the individual ate larger amounts before. Depending on body size, activity level and age, an appropriate change in eating habits can reap the desired results.

So for the long-term, consider a diet more moderate than The Zone or Sugar Busters!. Reduce the portion sizes of carbohydrate foods, limit your fat intake, participate in some form of daily exercise (even walking short distances can help) and understand your eating behavior.
Find the unhealthy pattern and change it. It may be easier than you think!

Reprinted with permission by Port Folio Weekly Health Quarterly, February 23, 1999.