You don't need to have breakfast. The advice you hear is a myth:

https://www.theguardian.com/lifeandstyle/2016/nov/28/breakfast-health-america-kellog-food-lifestyle

When you spend over 14 hrs fasting you may be on a state of Ketosis, especially if you've done that for years. Being in Ketosis is basically using fats to produce energy instead of glucose (sugar). There is solid research on the benefits of relying on ketones to produce energy.

I've been basically doing the same thing as you, for a year and half now. It's called intermittent fasting. Having a window of 4-6 hours of eating and then nothing besides coffee/tea. And it feels great.

I also avoid sugars (fructose is considered sugar too, even if it's in fruits). From an evolutionary perspective you're doing things right. Our diet relied on proteins, fats and above-ground plants long before we discovered agriculture and grains 10,000 years ago.

For more info, look up Dr. Dominic D'Agostino, he's doing research on keto diets and how it may prevent cancer cells.

You can start with this podcast if you're into podcasts: https://tim.blog/2016/07/06/dom-dagostino-part-2/