If hunter gatherers had a "better and healthier" lifestyle, why did people become agriculturalists?

People had started growing plants and cattle-herding when they grow tired of moving from one place to another. Hunters and gatherers are nomads. They tend to move when they think that the resources are scarce in their location.They believed that if they could grow these foods instead, they would be able to feed their families and community. 

It's A, the political and culture revolution in Russia and China