Try not to eat between breakfast and the following day's breakfast. You'll be shocked at how difficult this is. Our ancestors went for days without eating; there were not refrigerators, or even agriculture, for most of humanity's existence, so we either had fresh food and ate, or we starved.

Because of this eating/starving cycle, a symbiosis formed, between us and the bacteria that live in us. Think of these bacteria as an extremely blue collar workforce; it's hard work, but you get the job done and then you die. When times are good the populations grow up, but they always stay in balance.

Fast forward to today, and most of us have abundant food available anytime of the day, and for many of us, this food contains such cheaply available calories (glucose, fructose, etc.) that we have created a welfare state for bacteria. Just like with a human welfare state, it's no longer the bacteria that serve the most important purpose that thrive, it's the bacteria that reproduce at the fastest rate, given the available energy medium. As a result, our immune systems are partially tasked with destroying bacteria that have no business existing in our bodies in such high numbers. This wreaks havoc on our health more than any other thing we do.

There are various schools of thought when it comes to fasting, but, as a general principle, fasting, to some degree, on a regular basis, creates a biome inside of you that more closely represents how we naturally existed before the advent of french fries and corn bread.

None of this is medical advice and I am not a medical professional.