I'm vegetarian.. I've thought about being vegan but personally I'd struggle to cut out ALL dairy and products with eggs etc... Perhaps being vegetarian could be a possible compromise? But if this is important to you I say stick with it. I get fairly sick of people judging my choice not to eat meat and telling me it's unhealthy to be a vegetarian - as long as you eat a balanced diet, do your research, and get the nutirents you need (plenty of alternative sources these days) then its NOT unhealthy not to eat meat. In fact I think a lot of westerners eat more red meat than what is healthy. I can only suppose your T wants you to eat lean meats like turkey or chicken instead of fattier vegan options? (Not sure what those fattier vegan options would be!?)

Anyway, my point is: do what's right for you! (Ts aren't actually always right, even if they think they are )