The Yogic philosophy states that all matter in the universe is the interplay of energies with 3 basic types of qualities, also known as Gunas. The 3 primary gunas, Sattvic, Rajasic, and Tamasic are believed to emerge from Prakriti, a primordial ethereal matter. These gunas exist within all beings and objects and are essential for all aspects of nature.
Sattva, Rajas, and Tamas must exist in equilibrium at all times. But we humans, being the highly superior and evolved species that we are possess the unique ability to alter the balance of the 3 gunas within us. Yoga helps us achieve this. The delicate balance can be altered (any one guna can be increased or decreased) through diet, lifestyle practice, and thoughts.
Here are the 3 gunas explained with respect to diet, in detail:
Sattvic
Sattva is the base of a higher state of consciousness. The sattvic diet includes whole grains, legumes, and fresh fruits and vegetables that grow above the ground. The yogic lifestyle is a strong advocate of the sattvic diet, the requirements of which are:
Rajasic
Rajas is the foundation of motion, energy, and pain. Rajasic foods include all sattvic foods that are deep fried, overcooked, or eaten in excess, and extremely spicy foods. The Rajasic diet:
Tamasic
Tamas is the base of ignorance, darkness, inertia, and inactivity. Tamasic foods include heavy meat, spoiled food, or chemically-treated, processed, and refined foods, all of which:
Yoga emphasizes on increasing the Sattvic guna because it embodies the power of harmony, balance, light, and intelligence and helps achieve a higher spiritual level. Increasing sattva will help reduce rajas and tamas. This can be done by eating sattvic foods and indulging in activities that promote positive thinking.