Some people have black hair, some people have blonde hair, and some people have no hair. Some people are tall and some people are short. Some people have dark skin and some people have light skin. Some people are bow-legged, others are knock-kneed. Although the hardware may look different, the operating software (OS) is quite similar among us. The human body has many innate programs for survival. It’s programmed to move, breathe, take food in for energy, and gain fat or lose fat depending on the circumstances.

For example, if you’re being chased by a lion or a bear or any other animal that could rip you apart at will, you would run like hell for your life. In 30 seconds or less, your fate would be decided. If you’re one of the lucky ones and you happen to survive, your body inputs that experience and adjusts it’s OS appropriately. The program now reads something like this: get lean and fast so that next time you run like Usain Bolt to get away from a predator, you have a better chance to survive. Our ancestors entered that data a long time ago. So now, when you go out in the real world and do several intervals where you “bolt” it for 30 seconds, your body loads that program that’s been sitting idle in your applications folder and executes accordingly: Get lean and fast!

There’s another program in place as well, one that provides a different message. You see, historically we were nomadic people, moving from one place to another in search of a better environment for survival. Our ancestors would go on long treks to find a new home and in the process, their body would remove unwanted baggage (i.e., dense muscle) to make the journey easier. If they survived, they would adapt. The body would then update its OS to facilitate the next journey. The 2.0 version would read something like this: store less muscle and more fat (energy). So today when you perform slow, steady-state, rhythmic activity at a low to moderate intensity for a prolonged period of time, your body loads up that program and executes accordingly: Get small and fat!

The body is a highly adaptable organism. We would not have survived all these years without the ability to adapt. If you keep trying to override the code that’s programmed inside of you, eventually the system will crash!

Take-Home Message: If you do a lot of aerobic exercise with your heart rate in the “fat burning zone” yet you can’t seem to lose any body fat, try loading a different program. Give high-intensity interval training a shot and see how your body adapts. If you survive, it may be just what you need to get lean and fast!