Olive oil, peanut butter, mixed nuts (low sodium if possible), potatoes are some of the most common ways to get vegan calories I believe. but you're right it depends on a person's diet. Seth Gross was on the all carnivore diet, so he hasn't eaten anything plant-based in several years at this point. He seems to still be alive haha. I think humans are very adaptable, so our diet can be more self-directed to remediate whatever issues we may have going on personally.