Tuesday, November 5, 2013

Burn Fat as Fuel

When starting an exercise program, people have a variety of goals but one of the most mentioned is the desire to lose weight.  Over the years “life” can get in the way of a healthy life style and one of the not so welcome gifts from a lack of physical activity are a few extra pounds in all the wrong places.  Some writers have termed the American diet and way of life “Disease of Affluence” because we are less active and consume a diet high in saturated fats and refined sugars.
Although any level of exercise coupled with a healthy diet in moderation will help shed those unsightly pounds, teaching your body to burn its fat stores as fuel is the key to increased weight loss.  According to Stu Mittleman, an ultra-endurance athlete, people have about 160,000 calories of energy in their body.  Of that, only 4,500 to 5,500 calories are in the form of sugar.  What happens when we exercise at very high intensities for a short period of time, our body burns the sugar as fuel while the fat stores go largely untouched.  When the sugar is gone, the body starts to shut down and exercise becomes increasingly difficult as you have hit “the wall.”

The key is to train your body to burn fat as its primary source of fuel. Not only will you be able to exercise longer, you will be able to lose weight more quickly and feel better when you are done.  To have a complete exercise program, you still need to have shorter more intense bouts of exercise but you need to make room for one to two days where you slow down and stay well below your lactate threshold.  So how do you train your body to burn fat and not sugar?
First, take one or two days each week and dedicate to long, slow runs or other cardio activities.  This will be different for every individual based on their fitness level. The best indicator you are going slowly enough is that you can easily carry on a conversation with another individual without feeling out of breath.  You want to gradually increase your distance and a steady state of activity, keeping your heart rate elevated but stay below 60% of your max ability.  For those with heart rate monitors, you want to stay in Zone 2.
Second, extend your warm-up sessions.  If you take off running or start exercise without easing into activity, your body will sense the change in activity and trigger the sugar stores for fuel.  Nice easy stretching or walking will do the trick.
Finally, practice exercising in a carbohydrate depleted state.  US Olympic Marathoner Meb Keflezighi recommends this strategy.  This means restricting, but not eliminating sugar intake both before and during long cardio exercise sessions. Be sure to monitor how you feel and take small doses of a sports drink or other carbohydrate to maintain adequate blood sugar levels. 
Chris is a Certified Personal Trainer and exercise and endurance enthusiast.  He competes yearly in numerous running races, marathons, ultra marathons, triathlons and other endurance events. 

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