When you exercise you are going to either burn calories from the breakdown of Fats or Sugars (carbohydrates or proteins) for energy. Keep in mind your body only has 3 fuel sources. Fats, Carbohydrates or Proteins (lean muscle).
What determines if you are going to burn fats or sugars is the intensity of your workout!
When you walk and do an easy aerobic workout, most people (not all) will be using ‘aerobic’ respiration, which allows your metabolism to burn fats, carbs and proteins for energy.
As you increase your pace and start walking faster or jogging (this applies to all aerobic like activities like biking, swimming, hiking, dancing, etc.), you will reach a point to where you go above your aerobic threshold and activate ‘anaerobic’ respiration. This is when you start breathing a little heavier and can’t hold a normal conversation without gasping for air.
>What’s important about your aerobic threshold, is that when you start exercising a little more intensely – your metabolism switches and can ONLY burn carbohydrates and proteins (lean muscle) for energy.
Let me say it this way….a nice easy, aerobic (walk, jog, bike, hike, dance, swim) workout, where you stay below your aerobic threshold – will allow your metabolism to burn mostly fats for energy. This is a good thing and important if you are looking burn the fat and flab off your body.
But, now let’s do the same workout described above, but instead you’re pace is a little faster and your heart rate is a little higher, which takes you above your aerobic threshold. Now instead of burning FATS for energy during this workout, your metabolism has shifted and is now having to burn carbs and proteins (lean muscle) for energy. Which is OK. If that is your intent!
The point I am trying to make is don’t make the mistake and turn your aerobic, FAT burning workout into a workout that ends up burning your lean muscle.
This happens all to often, especially those on low carb diets who don’t have enough glucose in their body to get through their workout. Or those who wake-up early and don’t put some glucose in their body to get through their workout….and their body has to burn protein (lean muscle) for energy. Yeah, they burned calories and lost weight, but they didn’t lose the fat and flab.
The reason they lost weight, was because they burned-off lean muscle, when they were hoping to burn-off the fat. This is why it is so important to learn how to Train Smart. And why just because you are burning calories, doesn’t mean you are burning calories from FATS. It’s the intensity of your workout that determines if you are burning fats or sugars for energy. Don’t make the mistake of burning lean muscle when you were hoping to burn fat!