Our bodies are amazing machines and have the ability to run off of two different fuel sources depending on need: glucose and fat (aka, ketones). However, due to our usual eating patterns most of us only run off one of these fuels.
In reality, our bodies are actually most similar to a hybrid car, which can run off of both electricity or gasoline fuel. Similarly, we have two primary sources of energy: glucose and ketones (our super fuel). Glucose is indeed a fuel that can be used to move our bodies quickly for brief periods of time, but the energy doesn’t last and we may start to feel hungry, fatigued, unfocused, or all of the above. This creates a vicious cycle where frequent stops at the pantry are required throughout the day unless our brain and body are able to switch to using ketones for energy.
In contrast to traditional gasoline fueled vehicles, electric cars run very efficiently and have lots of power and emit few waste products. Driving the vehicle puts little stress on the engine and other critical parts so the car experiences little damage. Additionally, the car can function at a high level all day long and only needs to be charged (re-fueled) every now and then. Finally, electric cars get their energy from the rechargeable batteries inside of them, and thus their energy supply comes from within – it just needs to be activated. This is why an electric car would be the closest analogy to what a dream metabolism looks like, being able to run off your body’s super fuel (ketones) all day long.
Unfortunately, most of us are not like electric cars, but more like a 10-year old vehicle which inefficiently uses fuel while emitting lots of metabolic waste products. And those of us who are at a true metabolic disadvantage are more like diesel trucks emitting tons of exhausts and using large amounts of energy to function so frequent stops at gas stations (or food pantries) are required