The Buddha commonly depicted in statutes and pictures is a different person entirely.  

Siddhartha Gautama, who later became the Buddha, was a rich and young who was shielded from all pain and sorrow. He lest the palace as a youth for the first time and became aware of loss, pain, suffering, and impermanence. he asked why all things exist, and seek the path to defeat them. This led him to pursue traditional Hindu asceticism, involving enormous physical deprivation and self- discipline, including lengthy fasting. This is the bony, anorexic, pre-enlightened Buddha.

After realizing that the answer he sought was not in the immolation of the flesh, he went to the opposite extreme, attempting to find enlightenment in libertine self-indulgence. This also proved fruitless and he began to travel. Enlightenment came to him when he sat to rest under a Bodhi tree. This is why the fat, laughing Buddha is often depicted sitting under a tree.