They fuel your body and are directly affected by the design of your exercise program.
Sorry, this is going to get a little science-y but I promise it will be all worth it by the end!
There are three major energy systems for your body: the creatine phosphate system, the glycolytic system, and the oxidative system. Each of these systems works in very different ways to ensure you keep functioning and keep moving and which system you use directly influences your body composition.
This topic is pretty complex. There are textbooks and entire veins of research dedicated to each of the systems and as of yet they are not fully understood. This week and next we will take a quick look at the two major systems most likely to be pertinent to your exercise program and goals.
I will endeavour to keep this a simple as possible! If you work with any health and fitness people ask them to explain it in a little more detail.
The Glycolytic System
This system is fuelled by glucose. You already know all about glucose. You know it as carbohydrate. Here is something novel for you: all carbs are the same!
That’s right, if you eat white bread, table sugar, fruit, carrots, broccoli, potatoes, sweet potatoes, rice, pasta, or any other ‘carb’ you can think of it all turns into the same thing: glucose. Your body breaks down all of these carbohydrates and turns them into glucose, which it then stores in your muscles and liver where it can be readily used to fuel activities relying on your glycolytic system.
So it doesn’t matter what carbs you eat to your body, it all gets converted to the same stuff. For your health what is important is the speed at which carbs are turned into glucose and what other stuff comes along with those carbs, as in vitamins, minerals, and fiber. Vegetables get converted more slowly and come with better stuff than, say, white table sugar, which gets converted extremely quickly.
The speed at which carbs are converted also have a direct effect on your hormones. The faster carbs are converted, the more insulin your body secretes to shuttle all that new glycogen into your muscles and liver. The higher your insulin the more cortisol must be secreted to bring your hormones back to baseline levels. And high cortisol levels are not good for you.
This fast speed and resulting hormonal effects lead to your cravings for sugar, makes you sleepy, and wreaks havoc with your blood sugars.
What does this glycogen do? It fuels your muscles. When you move or exercise your body preferentially uses glycogen as a fuel source. Even during aerobic based activities, your body will burn glycogen until your reserves are depleted before it ever delves into your fat storage for fuel. This is why you are often recommended to do cardio for at least an hour!
Why is all of this even important? When you eat carbs and they get converted to glucose your body wants to store it. If there are depleted levels in your body then you will store it in the muscles and liver. If those areas are all filled, then your body will convert the excess into body fat for future storage. Most of you will not want this to happen.
How does all of this relate to exercise?
You eat carbs, they are your fuel, your body wants fuel, and if you take in too much fuel you will get fatter.
See, easy as that.
You want to eat carbohydrates. They are good for you. The best time is right before and after your workouts. This is when you need to top up and then replenish your glycogen stores. At other times you are just maintaining; so moderate and lower carbs are a better idea.
You want to eat enough carbs to keep your levels topped up -especially if you are active. If you do not have enough stored fuel and you ask your muscles to work than your body responds by breaking down muscle tissue to make more of that yummy glucose for fuel. It does this BEFORE it will break down body fat for fuel. That’s a fact.
You want to eat enough to keep your tanks topped up but no more. And you want to make sure to eat slow digesting versions with lots of nutrients.
You want to make sure your exercise is designed to maximize the use of glucose. You want to burn as much of your storage as you can and then top it back up. Why?
1 – Then all of the carbs you eat goes to fuel and your body will not have a reason to store extra body fat
2 – The exercise that mainly uses glucose is the same exercise that boosts your metabolism, builds quality muscle, increases strength, and makes you look better.
We will discuss more about this style of exercise in a couple of weeks once we take a look at your oxidative energy system!