Your body is made to store energy in your muscles, ready to use throughout the day to survive. When you do eat a little more than your body needs, it just stores it as fat.
If you work out in the ‘fat melting zone’ you’re using that stored fat for energy. But that only teaches your body to store more fat so you have it available for energy during your workout.
How to work out differently:
• do sets of exercises that are progressively intense.
• rest in-between each set.
• Exert yourself for no more than 12-15 minutes.
Why
For the first 2-3 minutes of a workout you burn ATP, or adenosine triphosphate. This molecule is the basic unit of cellular energy. It is stored in the muscle cells and is available at any time. It is also your high-octane fuel for intense effort.
There is only enough ATP for a few minutes of exercise. When your ATP stores are depleted, your body switches to glycogen, a carbohydrate stored in muscle tissue. Your glycogen stores will take you through about 15 minutes of exercise.
After both your ATP and glycogen stores have become depleted – about 20 minutes – you switch to fat. But if you stop before your body starts to use fat for energy, your body learns to store energy in your muscles, NOT store it as fat for later use.
Afterburn
It does this through the adaptive changes your body makes to prepare for the next time you ask it to perform that same activity. It’s called ‘afterburn’.
After intense exercise, you burn extra calories as your body repairs muscles and stores energy in them, and returns to its normal state. Since this can take from several hours to a full day, you will keep on burning calories long after the workout is over.
Research
A Colorado State University study measured the changes induced by exercising this way. People exercised for 20 minutes in sets of two-minute intervals, followed by one minute of rest. The researchers found that they were still melting fat at an increased rate sixteen hours after the exercise session. At rest, their fat oxidation was up by 62 percent (1).
In another study, researchers at Laval University in Quebec divided participants into two groups. One group cycled for 45 minutes without interruption. Another group cycled in numerous short bursts of 15 to 90 seconds, while resting in between (2).
The long duration group burned twice as many calories. So you might assume that they would melt more fat. However, when the researchers recorded their body composition measurements, it was the short-term interval group that showed the most fat loss.
In fact, the interval group lost nine times more fat than the endurance group for every calorie burned!
Body fat
This is why many endurance athletes have body fat percentages ranging from 10-20 percent, while athletes like sprinters and basketball players – who run in short bursts with progressive intensity – have a well-muscled physique and usually carry only 4-8 percent body fat.
In other words
You don’t have to do endless treadmill workouts and painful weightlifting sessions to lose weight. Instead, you can exert yourself for just a few minutes at a time, and challenge your body in a progressive way without depleting yourself.
(Source: newsletter Al Sears, MD)
1 Osterberg KL and Melby CL. “Effect of acute resistance exercise on postexercise oxygen consumption …” International Journal of Sport Nutrition and Exercise Metabolism, 2000 Mar; 10(1):71-81.
2 Tremblay A, Simoneau JA, Bouchard C. Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism. 1994;43(7): 814-818.
