Last week a client of mine asked me if it was better to do walking or jogging outside of our supervised sessions, to accelerate fat loss. She told me that she had watched a Youtube clip that discussed walking being better for fat loss, rather than higher levels of exercise. The first theory is that you burn more fat when you exercise at a low intensity. The idea is that your body uses carbs more and more as exercise intensity rises – this is the basis for target heart zones and the fat burning zone you see in books and on gym equipment.
What is missing in this picture is the TOTAL amount of energy. Let me phrase it this way: Would you rather have 20% of the money in your partner’s bank account, or 80% of the money in your own bank account? Your answer of course, should be that you don’t know. And what you should be asking is “How much money is in your bank accounts?” The reason is that you’d be pretty annoyed if you took 80% of my money, but my bank account might be empty. My partner, on the other hand, might be wealthy, and 20% of his money sees you retiring at 40! (I wish…).
So again, at low intensities (25% VO2max), you’ll see again that most of the energy comes from fat (75% in this case), with only 25% from CHO. But, the key is that the TOTAL energy, shown here on the y-axis, the green boxes above each bar show the total amount of fat burned in an hour – 24g, 37g and 23g per hour, at the three intensities.
The moral of the story, is that if your objective is to maximize fat burning, low intensity is not necessarily the best option. Rather, moderate intensity burns more fat per hour. However, as an Exercise Professional, I understand that other factors may limit the ability to exercise at a higher intensity (like jogging), but there are other exercise alternatives to reach your fat loss goals. Talk to your Optimum Exercise Physiologist to create an individualised fat loss program for you.