With the growing attention toward dietary fat's link to heart disease risk, some people ask a sensible question: Why not go all the way and eliminate fat entirely?

That'll scour out those clogged arteries, the thinking goes.The idea amuses nutritionists and cardiologists, who note that Americans currently get about 37 percent of their calories from fat. And that figure, based on numerous studies of the U.S. diet, doesn't seem to have changed much over the past few years.

The government and the American Heart Association recommend trimming the figure back to no more than 30 percent of calories from fat. There's plenty of evidence that eating even less would lower the risk of heart disease and some cancers.

But authorities figure 30 percent is the lowest the average American is likely to achieve in a world of french fries and premium ice cream.

The Chinese, however, obtain around 20 percent of their calories from fat and rarely die of heart disease. It's on the rise in Hong Kong, however, which has been adopting an American-style diet in recent years.

Dr. Dean Ornish, author of "Dr. Dean Ornish's Program for Reversing Heart Disease" (Random House, $24.95), devised a diet in which fat contributed fewer than 10 percent of calories. Combined with exercise and yoga, the diet opened up the coronary arteries of test subjects - the first time that was demonstrated without surgery.

There's a catch, however, for people who like meat: The Ornish diet is vegetarian.

Realistically, how low could one go? Could you actually cut fat out of your diet completely? Theoretically, you almost could. Some vegetables and fruits have close to no fat whatsoever.

But it wouldn't be easy to do, and it wouldn't be sane. Fat and cholesterol serve functions in the body; cells and tissue couldn't be made without them. The real question is: How much does the body need?

Scientists like Ornish and Dr. Roy Walford, a UCLA gerontologist, believe the body could get all the fat it needs on a mere 10-15 percent of calories from fat. Others aren't so sure.

The key is not to go to extremes. Modest reductions in fat intake combined with exercise and stress management is much more likely to reduce the risk of heart disease than a radical program to get fat out of the diet.