The origins of yoga are a matter of debate. There is no consensus on its chronology or specific origin other than that yoga developed in ancient India. Suggested origins are the Indus Valley Civilization (3300–1900 BCE) and pre-Vedic Eastern states of India, the Vedic period (1500–500 BCE), and the śramaṇa movement. According to Gavin Flood, continuities may exist between those various traditions:
Various yogic groups had become prominent in Punjab in the 15th and 16th century, when Sikhism was in its nascent stage. Compositions of Guru Nanak, the founder of Sikhism, describe many dialogues he had with Jogis, a Hindu community which practiced yoga. Guru Nanak rejected the austerities, rites and rituals connected with Hatha Yoga. He propounded the path of Sahaja yoga or Nama yoga (meditation on the name) instead. The Guru Granth Sahib states:
The least intrusive weight loss methods, and those most often recommended, are adjustments to eating patterns and increased physical activity, generally in the form of exercise. The World Health Organization recommended that people combine a reduction of processed foods high in saturated fats, sugar and salt and caloric content of the diet with an increase in physical activity.
The Yoga Yajnavalkya is a classical treatise on yoga attributed to the Vedic sage Yajnavalkya. It takes the form of a dialogue between Yajnavalkya and Gargi, a renowned philosopher. The text contains 12 chapters and its origin has been traced to the period between the second century BCE and fourth century CE. Many yoga texts like the Hatha Yoga Pradipika, the Yoga Kundalini and the Yoga Tattva Upanishads have borrowed verses from or make frequent references to the Yoga Yajnavalkya. The Yoga Yajnavalkya discusses eight yoga Asanas – Swastika, Gomukha, Padma, Vira, Simha, Bhadra, Mukta and Mayura, numerous breathing exercises for body cleansing, and meditation.
Malaysia's top Islamic body in 2008 passed a fatwa, prohibiting Muslims from practicing yoga, saying it had elements of Hinduism and that its practice was blasphemy, therefore haraam. Some Muslims in Malaysia who had been practicing yoga for years, criticized the decision as "insulting." Sisters in Islam, a women's rights group in Malaysia, also expressed disappointment and said yoga was just a form of exercise. This fatwa is legally enforceable. However, Malaysia's prime minister clarified that yoga as physical exercise is permissible, but the chanting of religious mantras is prohibited.
Classical yoga incorporates epistemology, metaphysics, ethical practices, systematic exercises and self-development techniques for body, mind and spirit. Its epistemology (pramana) and metaphysics is similar to that of the Sāṅkhya school. The metaphysics of Classical Yoga, like Sāṅkhya, is mainly dualistic, positing that there are two distinct realities. These are prakriti (nature), which is the eternal and active unconscious source of the material world and is composed of three gunas, and the puruṣas (persons), the plural consciousnesses which are the intelligent principles of the world, and are multiple, inactive and eternal witnesses. Each person has a individual puruṣa, which is their true self, the witness and the enjoyer, and that which is liberated. This metaphysical system holds that puruṣas undergo cycles of reincarnation through its interaction and identification with prakirti. Liberation, the goal of this system, results from the isolation (kaivalya) of puruṣa from prakirti, and is achieved through a meditation which detaches oneself from the different forms (tattvas) of prakirti. This is done by stilling one's thought waves (citta vritti) and resting in pure awareness of puruṣa.