First, what is yoga? At its root, the word means "yoke" or "unity", with the purpose of our practice to bring our self to its highest nature and greatest good. Yes, that sounds very fluffy, but at its core, the yoga sutras (essentially the ancient yoga instruction manual) have a very simple message - slough off all the unnecessary egoism, materialism, delusion, and dishonesty to achieve enlightenment. Ok, not all of us are seeking enlightenment, but there are some important take-home messages from the yoga teachings, with particular implications for diet.
There are eight limbs of yoga, components of a whole being, with the yama (abstentions) being one of those fundamental principles. In training, we learned that the first yama is 'ahimsa' or to avoid causing any harm. There are many ways you can construe this - not physically hurting someone, not causing offense or grief, staying healthy, and not eating meat. You heard right. Vegetarianism is very much entwined in the yogic philosophy.
Moving on to the Bhagavad Gita - the gospel of Hinduism and another backbone of yoga - in which the three gunas (qualities of material nature) are outlined - sattva/purity, rajas/activity/passion, and tamas/inertia. These are often applied to foods, where sattvic foods, such as fresh and whole foods are preferred above all. Rajasic foods tend to agitate the body and destroy equilibrium with the mind, but some (such as chocolate and nightshades, mmm...) play a critical role in our diet. Tamasic foods are heavy and drag the body and mind down, and include meat, alcohol, stale foods, and certain staples like onions and garlic. Another school of thought to stick in our apron pockets.
One last angle through which we looked at food choices is through body and personality type. Ayurveda examines lifestyle through one's dosha - mind and body type. Certain foods are better for certain types. Vata dominant elements are air and space, and tend to need hydrating and warming foods. Kapha is earth and water, thriving on easily digestible or raw foods. And Pitta (me!) is mostly fire with some water, seeking warm and sweet, but not hot or sour. I strongly encourage you to take the quiz and gain a new perspective on what your body and might need for nourishment.
Now I have to admit that this post was rather selfish. I accomplished some studying and you had to listen to me prattle on. That said, I hope that you gleaned some insight into diet, mind, and body. And as my instructors keep stressing, "this is not for a grade, this is for life!"