Glucose fuel Vs Fat fuel

When do we use glucose fuel vs fat fuel?

In our sedentary lifestyles, we need the kind of energy that fuels us slow and steady throughout the day instead of something that gives us energy in spurts and leave us tired soon after.
The former is what we get through fat fuel, that is when our body burns fats for producing energy. The latter is glucose fuel, which gives a sudden energy rush whenever you eat anything that converts to glucose, IF you are not insulin resistant yet.
If you are insulin resistance, your cells are not sensitive to receive glucose for conversion to energy and you experience constant low energy.

We spend 90% of our lives in resting zone or Z1, very small part in Z2, hence fat energy is the best energy for slow, steady and sedentary lives where most of our work requires good clarity in brain function.
As the zone increases, the need for glucose energy also increases.