The skinny on fat: Debate rages on pros, cons of low-fat diet

(PhysOrg.com) -- In recent years a fierce debate has raged among nutrition experts over the wisdom of prevailing dietary guidelines that emphasize eating less saturated fat. Two experts from the UNC Department of Nutrition cut through the chatter and explain what you can do to eat healthy.

If you love bacon, butter and fried chicken, the idea that a high-fat diet might be good for you can be seductive. Robert Atkins, the author of bestselling diet books, suggested that carbohydrates, not fats, were the true diet villains. Meanwhile, articles from The New York Times to The Los Angeles Times have also advanced the notion that fat isn’t as bad for you as conventional wisdom suggests.

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.