It depends on person to person. But i don’t believe in losing of intelligence due to vegan.
Its not so correct.
Thinking of options other than meat-eating is itself a sign of evolution. Being forced to consider alternatives is a key aspect of what drives evolution. Some say insect farming and eating will be a key aspect of how we consume in the future. Evolution is not about some idealized end-goal; it is an ongoing process with many possible outcomes. The biological magnification engendered by our consumption will force us to think of alternatives, whether we want to or not. In this scenario, refusing to consider alternatives to meat-eating might be detrimental to survival.