Dr. Walter Willett, Chairman of the Department of Nutrition at the Harvard School of Public Health, explained on The Early Show the new data show a diet that adheres to alternative nutrition guidelines significantly reduces the risk of chronic disease.
The researchers rigorously assessed the diets of more than 100,000 men and women. They found that the reduction in risk was nearly twice as great for those whose diet met new guidelines when compared to those whose eating patterns reflected the current United States Department of Agriculture (USDA) guidelines as laid out in the food pyramid. The findings appear in the December issue of the American Journal of Clinical Nutrition.
The current pyramid emphasizes large amounts of carbohydrates, doesn't make a distinction between types of fat or protein and lumps red meat, chicken, nuts and legumes together.
Willett say the USDA pyramid is severely out of date, doesn't reflect the latest research on nutrition and weight control and might be contributing to obesity and health problems. He and his colleagues developed a food guide pyramid based on the best available science and examined how people who followed it did over the following 10 to 15 years. They found that those who followed the guidelines had substantially reduced risks for major disease. These benefits, achieved by healthy dietary choices, are in addition to those from weight control and regular physical activity, which are also very important.
This new healthy eating pyramid puts daily exercise and weight control at the base, recommends eating whole-grain foods at most meals and suggests eating vegetables in abundance. He places emphasis on plant oils such as olive, canola and soy, and he gives fish and poultry a higher profile than red meat, which he recommends eating sparingly.
Willett objects to the fact that the government pyramid doesn't distinguish between types of fats and lumps them all together at the top with the advice to use sparingly. He says not all fats are equal.
Two types of fat — saturated fat, found in whole milk and fatty red meat; and trans fatty acids, found in many margarines and vegetable shortenings — should be limited because they contribute to the artery-clogging process that leads to heart disease, stroke and other problems. But, he says, monounsaturated and polyunsaturated fats found in vegetable oils, nuts, other plant products and fish are good for your heart.
The number-one problem in the American diet, according to Willett, is too many calories, whether from fat or carbohydrates, in relation to our level of physical activity. Trans fat is also a major problem. This kind of fat is found in many kinds of margarine and other foods, especially fast food, but it is actually worse for your arteries than lard.
Americans, particularly teens, are eating large amounts of it in the form of fried, fast food. Trans fat developed from the notion that saturated fats are not good for you, so therefore, anything else must be better, and margarine was promoted. Trans fat not only increases levels of 'bad' cholesterol in the bloodstream, but it also decreases levels of 'good' cholesterol.
A relatively new concern is glycemic load, which results from carbohydrates that increase blood sugar levels. The USDA Food Pyramid promotes eating complex carbohydrates without differentiating among them, but there are major differences. For example, the body breaks down glucose in a potato more rapidly than pure sugar, spiking glucose levels in the blood and increasing the risk of diabetes.
Willett encourages a shift away from the "low-fat mantra" that has dominated nutritional advice for the past 15 years, instead focusing on types of fats and carbohydrates and emphasizing fiber and whole grains. He says as long as people eat healthy fats, it may not be necessary to limit dietary fat as much. Not only are some fats good for you, but people also tend to replace fat in their diets with foods high in sugar or refined carbohydrates.
A lot of people think that a plain bagel with jam can be a healthy thing to eat in the morning, but Willet says it is actually one of the unhealthiest duos you can eat because it has a high glycemic load. You'd be better off with scrambled eggs cooked in corn oil or a whole-grain cereal.
The government is considering changes to its pyramid to make it fit for the times. The final verdict on any changes won't be out until 2004. The USDA also is reviewing new nutrient recommendations from the National Academies' Institute of Medicine, which include advice on subjects from dietary fiber to daily activity. They are looking to see if the servings in the food guide pyramid meet the new recommendations.
When it comes to advice for losing weight, Willett says focus on the quality of your diet and make sure you feel satisfied at the end of the day. You can eat good food in reasonable quantities and still lose weight. Stay away from refined carbohydrates and sugars and keep an eye on the calories, whether from fat or carbohydrates. Also, exercise is very important. You should develop a plan that you can maintain permanently.
More than 100,000 men and women were chosen for the study from the Health Professionals Follow-Up Study and the Brigham and Women's Hospital based Nurses' Health Study. The participants were sent detailed food frequency questionnaires assessing how often they consumed various foods. It also emphasized the quality of food choices, such as white meat over red meat, whole grains over refined grains, oils high in unsaturated fat over ones with saturated fat and multivitamin use.
The researchers found that men whose diet followed the guidelines of the Alternate Healthy Eating Index lowered their overall risk of major chronic disease by 20 percent and women lowered their overall risk by 11 percent compared with those whose diets least followed these guidelines. Men and women whose diet most closely followed the guidelines lowered their risk of cardiovascular disease by 39 percent and 28 percent, respectively.
The alternative guidelines reduced risk for chronic disease much more than the federal guidelines; men whose diets followed the federal recommendations reduced their overall risk by 11 percent and women by only three percent.