pre-Middle Path, later renounced by the Buddha
http://www.accesstoinsight.org/lib/auth ... el390.html
52. "Sariputta, there are certain recluses and brahmans whose doctrine and view is this: 'Purification comes about through food.' They say: 'Let us live on kola-fruits,' and they eat kola-fruits, they eat kola-fruit powder, they drink kola-fruit water, and they make many kinds of kola-fruit concoctions. Now I recall having eaten a single kola-fruit a day. Sariputta, you may think that the kola-fruit was bigger at that time, yet you should not regard it so: the kola-fruit was then at most the same size as now. Through feeding on a single kola-fruit a day, my body reached a state of extreme emaciation. Because of eating so little my limbs became like the jointed segments of vine stems or bamboo stems. Because of eating so little my backside became like a camel's hoof. Because of eating so little the projections on my spine stood forth like corded beads. Because of eating so little my ribs jutted out as gaunt as the crazy rafters of an old roofless barn. Because of eating so little the gleam of my eyes sank far down in their sockets, looking like a gleam of water which has sunk far down in a deep well. Because of eating so little my scalp shrivelled and withered as a green bitter gourd shrivels and withers in the wind and sun. Because of eating so little my belly skin adhered to my backbone; thus if I touched my belly skin I encountered my backbone, and if I touched my backbone I encountered my belly skin. Because of eating so little, if I tried to ease my body by rubbing my limbs with my hands, the hair, rotted at its roots, fell from my body as I rubbed.
"When one thing is practiced & pursued, ignorance is abandoned, clear knowing arises, the conceit 'I am' is abandoned, latent tendencies are uprooted, fetters are abandoned. Which one thing? Mindfulness immersed in the body." -AN 1.230