Is fat where it's at?

A low fat diet is best for health and performance; the lower the better--right? Only up to a point. First, there are many nutrients that can't be used without fat. Further, there are good-for-you fats that help to optimize health like monounsarurated fats (olive oil, for example). And a diet with too few fat calories is not likely to supply you with other important good fats. Here's more evidence that a diet too low in fat isn't good for runners.

Researchers gave 25 male and female runners (about 42 miles per week) a low fat (16%) diet for four weeks, and a normal diet (31%) for another four weeks. Twelve of the subjects increased their fat intake to 44% for the remainder of the study period. All of the diets were designed to have the same number of total calories. However, not only was the endurance of the runners while on the lowest fat diets reduced (by 14% as compared to the normal fat diet), but their total calorie intake was down by nearly 20%. In addition, during the low fat diet, the runners' levels of essential fatty acids and some nutrients (especially zinc) were too low. There was no difference in performance between the normal and high fat diets. Although the study had flaws, these authors concluded that a diet as low in fat as 16% could compromise both health and performance.

Runners have higher than average caloric demands and your diet must supply adequate energy to meet your training needs. Because fat is calorie-dense, a very low fat diet makes it hard to consume enough food to meet your energy and nutrition demands. It was simply too hard for the runners in the study to consume enough food to meet energy demands. Shoot for 25% to 30% fat calories and focus on fats that come from foods like olive oil, fish, avocados, and nuts, and your energy needs and nutritional demands 'will be met for optimum performance and health.

(Journal of the American College of Nutrition, 2000, Vol. 19, No. 1, pp. 52-60; pp. 42-51; Calorie requirement calculations were obtained from the American Dietetic Association, www.eatright.org)

RELATED ARTICLE: Calculate YOUR Calorie DEMANDS

* Multiply your weight in pounds times ten. This gives you your basal calorie demand--what your body needs to do its basic work.

* Multiply that number by an activity factor-50% for most regular runners who are very active.

* Add the result to your baseline needs and you have a pretty good estimate of your calorie needs for a day.

* A 150-Pound runner's basal calorie demand is l,500, plus an additional 750 calories to fuel running, for 2,250 a day. If 25% to 30% of calories come from fat that would be 70 to 85 grams of fat a day.