One expert at the University of California, San Francisco argues that we should worry more about sugar -- which he calls both "toxic" and "evil" -- than about fat. Another expert at Harvard Medical School argues in a best-selling book that the U.S. Department of Agriculture's Food Guide Pyramid "actually steers you away from foods that can improve your long-term health."
These ideas, referred to collectively as "the alternative hypothesis," suggest that filling up on carbohydrates, which are found in foods such as cookies, bread, pasta and potatoes, is making Americans heavier and more prone to heart attacks, strokes and diabetes. The solution, advocates say, is to stop worrying about reducing fat in the diet. Instead, you should cut carbs.
Amanda Holliday, MS, RD, LDN, a clinical associate professor in the Department of Nutrition at the University of North Carolina at Chapel Hill, said that eating fat does play an important role in maintaining good health. You need to consume fats to obtain some vitamins, and the unsaturated fats found in plant oils, certain vegetables and fish can actually reduce the risk of cardiovascular disease.
Eating fats also makes you feel satiety, or fullness, she said: "We don't feel quite as hungry, and that may help with weight control."
But the consensus within the scientific community still supports limiting your intake of saturated and trans fats, said Suzanne Hobbs, DrPH, MS, RD, FADA, a clinical associate professor of nutrition and health policy at UNC. Most medical researchers believe that saturated fats, which are found in animal products such as butter, dairy and meat, increase the risk of cardiovascular disease. Trans fats, which are created during food processing, may be even more harmful than those that occur naturally.
When nutritionists began to advocate a low-fat diet decades ago, Hobbs said, they recommended that consumers replace fat in their diets with healthier foods. But then many companies started offering packaged foods that were low in fat but high in sugar and refined flour.
"The companies were really playing up the fact they were in low in fat, when in fact that didn't make them a healthy choice at all," Hobbs said.
In the midst of this advertising blitz, many consumers missed the message that achieving a healthy diet meant reducing their consumption of sweets, refined carbohydrates, saturated and trans fats, while increasing the intake of fruits, vegetables and whole grains.
Today, "that's still valid advice," Hobbs said.
Article: "The Great Fat Debate" in this article from the May 2011 issue of the Journal of the American Dietetic Association.
TIPS FOR A HEALTHY DIET
•Beware of diets that suggest avoiding entire food groups, such as high-protein, low-carbohydrate diets. Such diets may deprive your body of essential nutrients and increase your risk of cardiovascular disease, Holliday said.
•Rather than trying to eliminate a particular food group, you should aim for a balanced diet, Holliday said. When planning meals, she suggests that you imagine a dinner plate. Half of that plate should contain fruits and vegetables. A quarter should contain lean meat or protein, such as fish, skinless chicken, nuts or beans. The last quarter should contain healthier grains or starches, such as whole wheat pasta.
•Saturated fats are usually solid at room temperature. Examples include butter, lard and pork fat. Try replacing them with unsaturated fats, such as olive or canola oil. Avocadoes, nuts and fish also contain unsaturated fats.
•Avoid trans fats, which are healthy fats that have been transformed during processing into fats that won't spoil quickly. They're usually listed on food labels as "hydrogenated" or "partially hydrogenated" oils.
Source: University of North Carolina