We feed farm animals for than we do humans
This is argueably the single most shocking statistic in all the world. Although this statistic is about the United States, it holds true every where in the world. USA alone could feed 800 million people which they currently do to feed lifestock. Basically what this means is that we as a society feed farm animals, mainly to sell meat and meat products, with more than enough food to feed the entire world. USA alone can feed 3 times its own population. This means that there is absolutely no excuse for anyone in the world to be hungry, which is not the case as of now since over a 1 billion people live in poverty.
You may ask yourself, this is such a big problem, but how can one person do anything? Well this is almost too simple. Stop eating meat, and try hard to not eat any food that requires animals to produce, such as milk, honey, and eggs. This may be difficult at first, but this is because society makes it seem like we need meat when in fact it is not true. You can live a perfectly healthy lifestyle without meat. This is the most practical way that every person in the world could to do maximize the impact on the world in a positive light. To put this perspective, a cow eats more food than the average person. If we didn't need to feed and maintain cows, we can use that food for ourselves, and make sure no one ever goes hungry in the world.