UPDATE: Last week I was asked to speak to my grandson's middle school health class about fitness. To begin the discussion, I asked members of the class to define health and then to tell me how fitness relates to health. We finally arrived at the idea that health relates to the absence or prevention of disease, and fitness relates more to the ability to use our bodies and do physical things.

I drew a line across the board, with sickness on one end, health (or the absence of disease) in the middle and fitness on the other to illustrate the point that people can be healthy but still not fit, and that fitness was really the upper end of the scale combining both the lack of disease and the ability to function well physically.Later in the week, I ran across an article by Dr. George Sheehan in the February issue of Runner's World where he addressed this very issue. He told about a man wheeling his bicycle off the boardwalk complaining of severe chest pain. While waiting for an ambulance, the man said he had been biking 10 miles a day for two years and thought that he was very fit, but tests at the hospital confirmed that he was having a heart attack.

Why did this happen? How is it that a man who is fit could develop serious and potentially fatal heart disease?

Sheehan answered these questions by saying that fitness and health are really quite different. To him, fitness is the ability to do physical work. Health is the prevention of unnecessary disease and premature death. Although fitness can make the muscles more efficient, training alone will not make us healthy. Sheehan pointed out that the winner of this week's local road race may have a cholesterol level of 350 milligrams, and a daily exerciser may still have high blood pressure or even be overweight.

To Sheehan, fat is the enemy to health. The main coronary risk factors - high cholesterol, obesity, hypertension and diabetes - are all related to difficulties in metabolizing fat. And exercise still remains one of our most potent weapons. But first, we must attain a healthy diet of less than 30 percent fat and only 10 percent saturated fat.

Prevention of coronary disease requires attention to all the risk factors. All of us should know our cholesterol levels and whether we need treatment. We should know our family histories. We ought to be aware of blood pressure, clotting tendency, waist/hip ratio, diabetes, etc. Exercise alone can go a long way to correcting many of these abnormal findings, but not always. "We begin with exercise; then make the diet-exercise connection."

Was my discussion with the health class wrong? No. The continuum between sickness on one end and fitness on the other still makes sense to me. It does, however, imply that attention is paid to other aspects of total health, including a proper diet to reach the right end of the line.

RECIPES: Last week I promised to give you a few good low-fat recipes. This week's is for a breakfast banana shake to eat with whole-wheat toast (courtesy of the Lower Your Fat Thermostat Seminar recipe collection). Ingredients: 3 ripe bananas, cut into chunks; 1/2-cup skim milk; 1/4-cup nonfat dry milk powder and 1/2-teaspoon vanilla. Blend ingredients in blender until smooth. Pour into chilled glasses.