In the ayurvedic mind and ayurvedic wisdom, there is a concept of Guna which in Sanskrit words means “quality, peculiarity, attribute or tendency.” Guna is tattva or elements of reality that affects our psychological, emotional, energetic states. The gunas are described as being constantly influx and interacting with one another, in a playful way referred to as maya or illusion. The patterns of the interplay of the gunas can define the essential qualities of someone or something, and these patterns can greatly influence the path and progress of life. Ayurveda dictates that awareness of the gunas provides a guide to allow us to make choices to be more balanced, peaceful, and harmonious. Cultivating the ability to identify and understand the nature of the gunas brings us closer to seeing the universal truth of oneness. 

The 3 Gunas: Sattva, Rajas, and Tamas

The three Gunas are always present in all beings and objects surrounding us but may vary in their relative amounts. Humans can consciously alter the levels of Gunas in our minds and bodies. The 3 Gunas are inseparable from one another but can be consciously acted upon to promote their increase or decrease. Gunas can be increased or decreased through the interaction and influence of external factors, lifestyle choices, and thought. 

Characteristics of the 3 Gunas

• Tamas manifests itself as a state of darkness, laziness, inertia, inactivity, and impurity. It is the consequence of ignorance and it prevents all beings from seeing reality. Other tamasic qualities are disgust, depression, helplessness, doubt, guilt, shame, boredom, addiction, hurt, sadness, apathy, confusion, grief, and dependency.
• Sattva is a state of harmony, balance, purity, knowledge, and intelligence. It is the quality of goodness, joy, satisfaction, nobility, and contentment. It is free of fear, violence, wrath, and malice. It is the guna that people want to increase in order to reach the state of liberation. Other sattvic qualities are delight, happiness, peace, freedom, compassion, fulfillment, calmness, selflessness, fearlessness, and gratitude. 
• Rajas represent energy, passion, action, motion, change, and movement. The nature of rajas is characterized by a feeling of attachment, a longing for satisfaction and desire, and is strongly binds us to the fruits of our works. Other rajasic qualities are anger, fear, irritation, worry, stress, courage, rumination, determination, anxiety, chaos, and euphoria.

Managing our Gunas

Our mind’s physiological qualities are highly unstable and can quickly fluctuate between different gunas. the dominant guna of our mind will affect our perspective of the world around us. For say, if our mind is dominated by rajas, it will experience world events as chaotic, stressful, and demanding and will continue to react to happenings in this perception. Therefore, if we want to make progress along the road, we must practice self-observation and discernment to witness and not react to the activities of gunas. We must have the willpower and strength to consciously shift our thought and actions away from tamas and rajas towards sattvic balance and purpose. Here is what you can do:

• Lessen Tamas – avoid tamasic foods(alcohol, meat, and processed foods), overeating, oversleeping, inactivity, passivity, and fearful situations.
• Reduce Rajas – avoid consuming rajasic foods, like fried and spicy food, and stimulants such as caffeine. Avoid over-exercising, overwork, and excessive thinking. 
• Increase Sattva – to increase your sattva, you need to reduce both rajas and tamas, eat sattvic foods such as fresh fruits, vegetables, and whole-grain foods. Sattvic foods are fresh, pure, and grow above the ground, receiving their positive energy from the sunlight. By practicing yoga, and living a non-violent lifestyle, surrounding yourself with positivity, performing activities that bring you and others joy, you can increase your sattvic elements in your mind and body.

https://holisticayurveda.ca/the-ayurvedic-mind-sattva-rajas-and-tamas/