The healthiest breakfast cereal is not cereal. It's meat and eggs.

It can be exactly as convenient - I pre-cook mini egg-frittatas and beef patties, and microwave them for breakfast.

Before I became carnivore, I had been breakfasting on what a lot of people consider the healthiest breakfast - steel cut oats, with lots of fruits, nuts, and seeds (chia, flax, etc). I'd been eating that for decades.

What happened then, is that I learned about just how bad the evidence is for the health benefits of whole grains, fiber, fruits, nuts, seeds etc. I read this book - The Big Fat Surprise by Nina Teicholtz.

After that I slowly, over the course of a month or so, went carnivore. The book doesn't advocate carnivore, necessarily, but it opened my mind to it.

I still remember the day I tossed pre-made steel cooked oats into the garbage. I'd kept them around for a couple weeks, thinking that I'd like to alternate eggs and oats. Then I decided on the carnivore option. The reason I went full carnivore is because I felt so much better and more energetic, eating much more meat, and fewer plant products.

But my point is...I'd been eating what most people would consider a really healthy diet. That breakfast steel cut oats was characteristic of what I ate in general - very much following the food guidelines.

Long term consumption of massive amounts of carbs is just a bad idea. Homo sapiens have been primarily meat eaters for almost our entire evolutionary existence. Eating grains is just the blink of an eye, evolutionarily.

Here's a graphic from Dr. Kevin Stock - I think he goes by Carnivore Dentist.