You can sustain yourself perfectly without eating any animal or animal byproduct. In rich developed countries where alternatives are findable, there is just no

You can sustain yourself perfectly without eating any animal or animal byproduct. In rich developed countries where alternatives are findable, there is just no need for animal products. In less developed countries, it would also be achievable if priorities were set to do so. There is nothing inherently difficult about not eating animal products except access to the alternatives.