Hi Brian,
It definitely can be challenging as many vegans and vegetarians don’t exactly have healthy diets, or dietary habits for that matter. This can apply to meat eaters, too, but at least we have more choices to work with. Ultimately it boils down to what changes they are willing to make while receiving treatments from you. With vegans, it would be more challenging but easier for vegetarians to have a fairly well rounded diet. Some vegetarians are open to eggs, butte, fish or bone broth, so those can add some nutrition for building yin and blood.
Often, if find that dietary habits play more of role in peoples’ health, as in eating late at night, eating while multi-tasking, not chewing food, drinking too much while eating, ….. I would work with them on some of these, plus the obvious elimination/reduction of the stimulants such as sugar, spicy foods, coffee, chocolate,…. The rest, really, is up to them. Since you mentioned the Indian-American community, eating spicy may apply.
Hope this helps.
Armin