Fats As Fuel?!

by Liz Applegate, Ph.D.

Believe it or not. The obsessive skimping on fat could be harmful to health--and detrimental to your running performance as well Many people fear fat. Take my running buddy, Alan. At a recent lunch, I noticed that he opted for salad without dressing. He also declined a sprinkling of walnuts over his pasta, asking instead for extra bread. "I cut out added fat whenever I can," he said, citing his running and heart health as reasons.

He's one of the 60 percent of Americans who rank fat-cutting as their number-one nutritional concern. Problem is, this obsessive skimping on fat, while well-intentioned, is potentially harmful on a number of fronts.

Sure, eating lots of food oozing with fat, such as burgers and fries, does boost heart-disease risk. Yet some people don't get enough fat. This can make matters worse by driving up their levels of artery-clogging circulating fats (triglycerides). Following rigid low-fat diets may also contribute to moodiness and depression and, new evidence suggests, may even hurt your racing performance.

The big fat truth
In many ways, fat is good. Besides tasting great and helping you feel full, fat is just as important as vitamins and minerals. Special essential fats, called omega-6 and omega-3 fatty acids (found in nuts, vegetable oils, flaxseed and fish), are crucial for a strong immune system and healthy skin and nerve fibers.
Research suggests that our early ancestors ate much more of these omega fats than we do. Today, on the other hand, we eat mostly saturated and hydrogenated fats from animal foods and processed snacks. These modern-day foods provide hardly any essential fatty acids, particularly omega-3s. As a result, an array of chronic ailments may have developed-auto-immune diseases, heart disease, some cancers, multiple sclerosis and skin conditions (such as psoriasis)-most of which were nonexistent thousands of years ago.

Even the ratio of these omega fats is important. Too many omega-6 fats and too few omega-3s may contribute to a fragile immune system and weakened nerve fibers. While no one knows the exact amount of omega-3 and omega-6 fats you need for optimal health, researchers agree that upping your intake of fish, flaxseed (meal or oil) and nuts is a step in the right direction.

Fat and your heart
Getting up to 40 percent of your total calories from fat-as long as it's mostly monounsaturated fat, such as olive oil-can cut cholesterol levels and heart-disease risk, studies show. On the other hand, avoiding saturated fats and trans fats (found in processed foods) also helps keep your arteries clear.

The American Heart Association (AHA) currently recommends getting no more than 30 percent of your calories from fat (about 65 grams of total fat daily), with no more than 10 percent of those fat calories coming from saturated fats (roughly a 20-gram-per-day limit).

Some health professionals, however, advocate a much lower fat intake. Dean Ornish, M.D., famed cardiologist and diet-book author, says a diet with 10 percent fat protects his patients from further artery damage and helps heal those already-clogged arteries.

In a recently released statement, the AHA points out that these low-fat diets are not for everyone. For starters, Dr. Ornish and others who promote low-fat fare require you to accept a total package, which includes regular exercise, stress reduction and other dietary changes, such as eating more fruits and vegetables. It may be the combination of all these factors that's responsible for unclogging blocked arteries, not just the low-fat diet.

Also, for some individuals, a low-fat, high-carbohydrate diet tends to increase levels of triglycerides while lowering heart-healthy HDL cholesterol levels.

A very low-fat diet may also wreak havoc on your mood. In a study from the nutrition and psychiatry departments of the University of Sheffield in England, levels of anger and hostility increased in people who decreased the percentage of fat in their diet from 40 percent to 25 percent. Researchers suspect a diet that's too low in fat may alter the brain chemicals that control mood and behavior.

Fast fat
Besides keeping you healthy, the right fats in the right amounts may also keep you running. No, I'm not advising that you forsake carbohydrates. Eating carbohydrate-rich foods keeps muscle glycogen stores packed, and that's crucial for endurance performance. But fat is also a vital fuel source during long runs and other endurance efforts.

Researchers have long noted that endurance training turns your muscles into better fat-burners, and a handful of studies done at the State University of New York at Buffalo suggest a diet with 30 percent fat makes more sense for runners than diets with less than 20 percent.

In one of these studies, a group of runners who averaged 40-plus miles per week ate a diet with 17 percent fat for four weeks and then switched to a diet with 32 percent fat for another four weeks. At the end of each four-week segment, the participants ran to exhaustion during a treadmill test.

Result: The men ran 24 percent longer and the women 19 percent longer following the moderate-fat diet, compared to the low-fat one. A limited number of other studies have also shown improved endurance when already-trained endurance athletes switch to a higher fat intake for a week or more. I'm not suggesting that we "fat-load" rather than carbo-load before a marathon, but eating the right amount of fat all the time may ensure adequate fat stores for your long runs.

Your fat plan
Based on various studies and AHA recommendations, shoot for a diet that includes 30 percent of total calories from fat. The amount of fat, however, is much less important than the type. Here's how to focus on the right fats:

* Use olive and canola oils when cooking, instead of margarine and butter.
* Aim to eat at least 3 to 9 ounces of fish a week.
* Use walnuts, almonds and other nuts more frequently as a topping for cereal, yogurt or salads.
* Add ground flaxseed or flaxseed oil to your diet (try my flaxseed muffin recipe, left).

Avoid processed foods such as chips, crackers and other foods with hydrogenated fats (a source of trans fats). Select whole-grain products over refined versions for small amounts of essential fats. Include four to five servings of fruit and four to five servings of vegetables every day. This may sound like a lot at first, but you'll end up feeling more satisfied and will be less inclined to binge on empty sweets.

RunnersWorld.com