Molson Hart

People both on the carnivore diet and on the vegan diet claim to be full of energy (I basically have unlimited energy when I eat mostly meat). Could this be caused by our bodies optimizing for a single type of fuel? Has anyone tried both?

I never tried either, so I have low confidence in the following, but: is it possible that there is some selection bias and it’s the other way around, partially – only one who feels very energetic / only in a period in which one feels very energetic, he can maintain a fixed diet?

That's a good point. From my experience, many who try these "extreme" diets, should they not get significant benefits drop them quickly - why else would you restrict what your eating? There's another selection bias; if you believe that everyone has an optimal diet, people for who

the normal diet is giving them low-energy are more likely to try these drastically different diets.

I might also add that Italians, as far as I can tell, are, compared to other groups better suited for the modern diet. So, if you feel good doing what you're doing, keep doing it?

I agree it is most likely selection bias. I've done full on vegan and felt great. I've done keto and felt great. There's no "source of truth" when it comes to diet. But I will say - and I know this is controversial - our meat industrial complex is not sustainable

What you end up sticking with? Great on both diets? Any other interesting nuggets of wisdom from that? You're the first person I've ever come across who's done both. Usually, it's one or the other.

Well to be clear, I never did a carnivore diet. I ate essentially keto/paleo for a while: mostly meats and veges, no carbs. These days I am mostly plant based, which I mostly do for philosophical reasons. But I do eat meat still, and enjoy it. I've loosened up a lot.