Diet is an Important Factor Influencing Meditative Concentration.

Diet is also an important factor affecting meditative concentration (samādhi). If the body takes in too many nutrients beyond what it needs, the body will react; this then affects the conscious mind, whose reactions become somewhat restless and agitated, the mind is not pure, emotions are not easily controlled, or require forced restraint.

These nutrients include not only meat and fish, tobacco and alcohol, scallions and garlic, and other pungent and fleshly substances, but also vegetarian food. If vegetarian food provides excess nutrition, it will likewise cause excessive reactions in the body and emotions, increasing the burden on body and mind, making the mind less easily purified, and thereby affecting meditative concentration.

Therefore, many people complain that meditative concentration is difficult to cultivate; they should then examine their own dietary structure to see whether their nutrition is excessive and superabundant. Nowadays, because material life is rich and colorful, people crave the pleasures of the palate and nutrition, cherishing the physical body and delicious flavors too much, resulting in impurity of body and mind. Greed and anger are not easily subdued, afflictions are heavy, and of course meditative concentration cannot be accomplished, making the contemplative practice (vipaśyanā-caryā) and realization of the Buddha's Dharma all the more difficult. Thus, although such a Buddhist learner may be broadly learned, well-versed in theory, and eloquent, the inner realization is ultimately never accomplished; he merely becomes a disciple who only understands intellectually and an eclectic theorist. 

In the Śūraṅgama Sūtra, the World-Honored One required his disciples to abstain from pungent and fleshly substances and to subdue the desiring mind and the angry mind, so that their progress on the path would advance rapidly. But in modern society, material life is too abundant; even vegetarian food likewise affects the purity of body and mind, increasing the desiring mind and the angry mind, and the path cannot advance rapidly. This should draw the attention of us, the vast numbers of Buddhist disciples, to adjust our own dietary structure so as to facilitate our cultivation.