She is already proven wrong:
And by the book China Study itself. Have you read it?
Strong argument of eating a vegan diet:
A cow, or a horse, or a dog, or a cat -- is there any difference? They are all sentient beings, they all have feelings, they all want to live and they all love their family!!!!!
We all agree that it is morally wrong to cause unnecessary suffering and death to animals -- and condemn people who for example enjoy and promote killing innocent dogs just because they got tired of them. However, we must also acknowledge that all animal products-eating is unnecessary and is done merely for "taste" and "enjoyment". So if we want to be moral we must also act upon what we acknowledge -that causing unnecessary suffering and death to animals is unnecessary.
The plant-based foods that the more than 56 billion land animals (who have the sadly misfortune to grow up to become someones food) brutally slaughtered each year eats could feed more than 9 billion people.
15 million children are dieing of starvation in the world each year. Hundreds of millions don't get enough food. If we care of them we must let our eating habits reflect this. If everyone ate plant-based food, the food would suffice for everyone's need.
This is not the only effect. By eating animal products 3 times a day we teach our children that it is okay to take the life of innocent sentient beings, and that some individuals are of less value than others; instead of increasing our children's love and compassion by loving all sentient beings for their different qualities (just as many parents teach their children to extend their love and compassion for some dogs). I became a vegan this autumn and notice how this also increases my love and compassion for other humans, and not only all other animals.
This articles shows how eating animal products effects the environment and effects poverty and starvation: http://www.guardian.co.uk/commentisfree/2013/jan/22/quinoa-bolivian-farmers-meat-eaters-hunger
This book shows how our violence against other animals also leads to violence against us- the human animal: http://www.worldpeacediet.org/
Research -see e.g. the research referred to here: http://www.adelicatebalance.com.au/ - has proven that animal products are unhealthy.