Ever wondered why some days you feel completely flat in the gym and others it feels like there isn't enough weights to stop you? It all comes down to your little power houses called your 'mitochondria'! If you've ever wanted to know how to get every bit of energy out your body, then learn how to fuel these work horses!
Mitochondria are found in every cell of the body including your brain. They are responsible for converting food energy (carbs, fats and protein) into fuel for cellular activities and powering your cells to grow, divide and even
Your body, in very basic terms, has 3 types of energy; instant (sugars), efficient (fat) and reserve (amino acids). Your body will at all times use a combination of everything, however will favour one over the other at different times. Upon commencement of exercise, or during high intensity training, the muscles will mainly use instant energy in the form of glucose (sugar) because it is easy to break down and burn. After a period of time of exercise, your body will start to use more efficient sources in the form of fat. Fat is harder to break down as the molecule chain is longer, however provides much more energy (ATP) per gram (this is why fat is more calorie dense than protein or carbs). Eventually when your body is unable to break down fats and sugars fast enough (or has run out) it will start to burn your reserves (amino acids from the muscles) to help the Kreb cycle continue so you can continue burning energy. Creatine, a supplement that males and females can take, helps with converting ADP back to ATP for ready energy. This is why bodybuilders, sprinters and other high intensity athletes take the supplement, as it helps to increase energy availability during short, explosive exercises.
Soooo what does this all mean exactly...? If you're repetitively doing short, intense exercise such as weightlifting, circuits, sprinting etc. carb up! You'll need it. If you're doing low intensity, steady state cardio then you will still predominately burn carbs for the first 30-45mins, but will then turn to fat for most of your energy, meaning you still need to eat carbs for both exercise and normal functions, just not as much.