[mrabcx]

Vegan diets are prone to vitamin B12 deficiencies. Same with vitamin D.

[lagniappe]

Also prone to talking about it a lot, nobody has time to add all that talking to their diet.

[tasty_freeze]

Which is not a difficult to solve problem. Carnivorous diets can have their own problematic health outcomes.

[mtlmtlmtlmtl]

Also Iron. There are plant sources of iron, but they're not as easily absorbed.