In yogic philosophy, all matter in the universe stem from three substances or qualities. I will mention them briefly because your yoga teacher may use the terminology from time to time in class.
The qualities are tamas, rajas, and sattva. Tamas is a state of inactivity, inertia, overeating etc. Rajas refers to increased energy, over work, over thinking, attachment, and longing. Sattva is a state of intelligence, harmony, balance and “beingness”. These qualities exist in varying degrees in all matter and all aspects of nature. They are present in all beings and objects. Humans have the unique ability to consciously alter the levels of these qualities by encouraging their increase or decrease in the mind and body.
This
terminology may seem foreign to most of you so I will give a few examples. To reduce tamas avoid tamasic foods such as excess sugar, heavy meats, and processed foods, avoid overeating, over sleeping and inactivity. To reduce rajas, avoid over work, over exercising and excess material cravings. Rajasic foods include stimulants and very spicy food. Since Sattva refers to harmony, balance and joy it is prudent to increase this state by reduces the others. Sattvic foods include legumes, fruits, vegetables and whole grains. Strive for sattvic activities that bring you joy and foster positive thoughts. Helping others, learning a new task, and walking in nature are all sattvic activities. Originally all of the yoga practices were developed to create sattva in the mind and the body. Most yoga classes today aim to decrease tamas and raja qualities and increase sattva. For example enjoy a light healthy meal a few hours before class. When you bring your awareness to your breath and the present moment, your thoughts will more focused. When you balance effort and ease in your practice, your body and mind will be in harmony. You will be on a sattvic path.
I have just touched briefly on these 3 qualities of nature. This is all fascinating to me. My main resource was an article by Timothy Burgin a Kripalu and Pranakriya trained yoga instructor. If interested you can read his entire article on Yoga Basics.com