Dietary Fats and Endurance Training

By: Dr. Dan Shuman

Dietary fat may be the most misunderstood nutrient in endurance sports as well as the in general population. The confusion arises when food recommendations are based on fad, pseudo-science, or politics.

Around the mid 1980s, popular wisdom and the media got hold of the idea that since fat contained approximately 9 calories per gram (as opposed to carbohydrates and proteins which only have 4 calories per gram) that humans could fill up carbohydrate rich foods while cutting fat. Skip forward a couple decades and the nation is in the grips of the largest obesity epidemic ever. So, is fat good or bad? It certainly isn’t the bad guy the masses thought it was two decades ago; however, well-trained endurance athletes are not the masses, and nutrients work a bit differently in this population.

Athletes and non-athletes alike need fats. They provide essential fatty acids as well as fat-soluble vitamins and ensure that energy needs are met. The function of fat is extremely varied. It serves as a structural component in cell membranes, as a hormone component in testosterone and estrogen, and as a metabolic regulator involving gene expression. Perhaps most important for the endurance athlete, it serves as a main energy source during long events.

But what about the multitudes of carbs in the form of bagels, pasta, rice dishes and the like? Conventionally, these foods rich in refined carbohydrates replace dietary fats, and comprise the bulk of an endurance athlete’s diet. Glucose, which is the ultimate by-product of carbohydrate digestion, fuels the body’s metabolic pathways up to a certain point. However, dozens of studies have shown eating like this causes sharp spikes in blood sugar and insulin levels, thus stressing the pancreas and over time can increase the risk of diabetes. High carbohydrate, low fat diets also raise the “bad” blood fats (triglycerides) and they lower the “good” blood cholesterol (HDL), both of which can increase the risk of heart disease and tend to increase blood pressure.

How much fat is necessary and what kinds of fat are “good” fats? Some studies suggest that endurance athletes can handle over 50% of their daily calories coming from fat. While that may seem excessive, don’t be afraid to play around with your percentages as long as you are neutral in your energy expenditure. A lot of people experience lasting satiety from meal to meal, decreasing their need to snack by increasing their fat intake.

There are three basic forms of dietary fat: saturated, unsaturated, and trans. In general, the recommendation has been to limit saturated and trans fats as they raise cholesterol and triglycerides. There is an increasing debate on whether saturated fats are really all that bad. Just as scientist have discovered “good” types of cholesterol, there are good types of saturated fats. For instance, coconut oil is a good highly saturated fat.

You can add some avocados, nuts and seeds to the pre or post workout nutrition instead of a highly processed carbohydrate drink or bar. Be sure to eat some oily fish like salmon, trout, sardines or mackerel, or take a fish oil supplement. Limit your exposure to sources of fat like soybean, safflower, canola and corn oils. While they are polyunsaturated, these are prone to oxidize quickly which produces free radicals and promotes inflammation.

The bottom line is, don’t rule out fat from your diet - even certain saturated fats. Fat is an important key to health and long lasting energy. For more in-depth or personalized information, contact a local dietician.