Vegan Outreach is one of two top recommended organizations to donate to if you want to provide the most effective aid for the highest number of animals possible.
Effective Animal Activism (http://www.effectiveanimalactivism.org/) is based on the idea that we should do good well for animals. Altruism is great – but it also has to be effective, which is based around the idea of Effective Altruism (a more Utilitarian view of helping others).
One acre of land can produce only 250 pounds of beef, or 40,000 pounds of potatoes. And it takes 16 lbs of grain to produce just 1 pound of beef. Not only is going vegan (or at least vegetarian) better for the animals and for our health, but if we all did we could probably feed the entire world, and no one would have to go hungry.