Having renounced his former life, Siddhartha travelled from place to place, begging for his food and questioning all the holy men he met about their religious beliefs and practices.
All the holy men he encountered happened to seeking the same thing, attaining the complete annihilation of mind and body and thus entering into the state of becoming a pure being.
Many of these yogis believed that the only way to achieve this was by undergoing terrible penances such as gazing into the sun until their eyes would be dissolved away, by sitting or standing in rigid positions until their limbs would become immobile, or by starving almost to the point of death.
Eventually the Bodhisattva went to live in a forest which was by the banks of the river Nairanjan, For six years he would fast and perform all kind of penances, and although these weakened his body, his spiritual powers became strong. According to the tradition, while fasting, his radiant skin became dark and due to his emancipated state he ultimately became very weak and ill. One day a milkmaid went past and pitying his state offered him a bowl of milk, which he drank. Then he realised that he needed some food and after eating he began to feel strong again.
Eventually it became clear to Siddhartha that extreme physical discipline would not lead to intellectual liberation. This could only be achieved by calm meditation, an impossible task for anyone whose body is worn down by hunger and thirst.
Malnourished figures, with their ribs clearly showing are often used to depict the fasting Buddha in various postures.