A fasted state is when your body has not recently consumed food and is using fuels that are available to the neurons, such as glycogen, fat, and blood sugar. When glucose is available to neurons, they work best, and glucose is the preferred source of fuel for the brain. Fasting is not necessarily anti-growth, but it is not pro-growth. Fasting can increase clarity of mind due to elevations in epinephrine and norepinephrine. Fasting can also promote cellular repair and clearance of all kinds, while being fed promotes cellular growth of all kinds.