It would depend on why and how they went about it. But if they went about it properly (ensuring they were properly balanced diet wise etc) and did it for good reasons, I'd be proud of their living my their decisions or beliefs.
I want to say I wouldn't care because it's their views and their values, BUT! If she/he tells me to change my eating habits I will throw them out of the house. They didn't give birth to me, I gave birth to them. My house, my rules. And even when they are grown I don't need to hear them telling me to change my eating habits because it's not going to change.
I seriously cannot believe anyone opted for "Ashamed"
Allow me to give some impromptu parenting advice in the form of a rant :-)
If your son or daughter turns out to be someone who betrays their country by giving away U. S. state secrets to say a foreign government, ISIS etc OR if your son or daughter turns out to be a pedo, then your feelings of being ashamed are well warranted. Traitors and pedos are about as shameful a thing as a person can possibly be.
Alternatively, if your son or daughter turns out to be someone who chooses to abstain from eating animal products, who effin'' cares? It's really not that serious and besides now there's more ham and turkey for you on Christmas. The only parents who are ashamed of their kids being vegan are bad parents who never should have had kids in the first place.
I would be a bit worried about their health, you need to make sure on medical advice from a doctor that it is safe as the child of whichever age maybe lacking certain nutrients in the body that it can not produce on its own so just make sure your not missing and thing in your body that could make you fall very ill
I'm vegan. my kids (if I have any) will also be brought up vegan. however if they choose to eat meat I wouldn't hold it against them. I'd simply encourage them to choose free range, "humanely" slaughterd animals to eat.
Proud would be the right word from that list I guess. I'll probably try to raise my kids on a vegetarian diet anyways. If they decide to take it one step further and go vegan, I will be nothing but happy and supportive.
It's their life, so I wouldn't really care, if I had a child.
I wouldn't push my eating habits on my kid. (If I had one) I'd let them eat whatever they want as long as it's not hazardous for their health. I'm not vegan or vegetarian but if my child, even at a young age, wanted to be, I'd let them. So, if they chose to become vegan, as long as they don't try to convert me, I'm fine with it.