Maximize your fat-burning potential to be lean, fit and fast

Arctic birds can fly 47 mph for 100 hours at a stretch during their annual migration of 7,800 miles. Grey whales travel from Alaska to Mexico at 5 mph for three weeks without eating. Tarahumara Indians of Mexico have been known to chase deer until the deer collapses in exhaustion, its hooves worn away.

These incredible feats of endurance and speed are fueled by fat. Like migratory animals, the capacity to burn large amounts of fat for fuel is in the human genetic code. Unlike migratory animals, however, if humans dont use it, they lose the capacity to burn fat.

People who are out of shape instead have to rely on limited carbohydrate supplies for energy. One gram of carbohydrate has only 4 calories of energy compared to 9 calories in each gram of fat.

The more fat you burn, the more energy you can generate and the better your endurance.

A study of Chris Boardman, after he set cyclings famed one-hour time trial world record, revealed that he could burn 1 one pound of fat in three hours of riding compared to 18 hours it took for recreational cyclists to burn an equivalent amount of fat.

The ability to use fat for fuel is something you teach your body to do, and the benefits extend far beyond exercise. Exercise and diet strategies can develop your metabolic potential to burn fat, allowing your body to burn more fat all the time.

Someone who is just starting an exercise program can expect substantial changes in just two weeks. After 12 weeks, fat burning can be increased by as much as 40%.

Time your food intake. Try to avoid eating for the two hours prior to exercise. Best yet, exercise first thing in the morning on an empty stomach. When you eat foods that contain carbohydrate and/or protein, insulin levels increase in the blood. Insulin reduces fat metabolism in the muscle and blocks fat leaving the fat tissue. The end result is lowered use of fat for fuel.

It is also important to include two servings of "good fat" in your daily diet, such as salad dressings, peanut butter, avocado, almonds, salmon or olives.

Long exercise sessions send a strong signal to increase fat burning. For the first 20 - 30 minutes of an exercise session, or until you're warmed up, the fuel mix your muscles burn will be high in carbohydrates. After that, a combination of hormone release and increased oxygen supply will change the fuel mix to include higher amounts of fat.

Unfortunately, many people stop exercising just when their muscles are starting to burn fat.

After an hour of exercise and again at three hours, fat burning is increased even further. Include one long exercise session in your training program each week. Build up time by increasing the length of your longest session by 10 - 15 minutes each week.

Multisport athletes may want to do a long training session in each sport. More than that can result in excess fatigue, injury and illness and interfere with training.

How long you go depends on your goals. Someone who is exercising for basic fitness or weight control may want to build up to two hours of continuous exercise. A marathon runner would get the most benefit from a three-hour run. A cyclist or Ironman athlete may want to build up to five to six hours.

Successful ultra-runners have been known to have training sessions of eight hours. However, the point of diminishing returns appears to be three hours.

How hard you go makes a big difference in fat burning. During aerobic training sessions, your target heart rate should be at the top of the fat burning zone, or the intensity where your muscles are burning the highest amount of fat. For most people, this is around 65% to 70% of maximum heart rate. This is the point where you can hear yourself breathe, and any talking will be interrupted.

If you cant talk, youre going too hard. If you can chat with ease, youre going too easy and youre just not sending enough of a signal.

After basic fat metabolism has been established, sprint training can increase fat metabolism even further. However, it must be emphasized that a foundation of aerobic training and strength should be built first.

Deborah Shulman, Ph.D. is a physiologist specializing in nutrition and sports performance. She works with all levels and types of athletes. For information on her and available programs, visit or contact her at

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