The chronology of completion of these yoga-related Early Buddhist Texts, however, is unclear, just like ancient Hindu texts. Early known Buddhist sources like the Majjhima Nikāya mention meditation, while the Anguttara Nikāya describes Jhāyins (meditators) that resemble early Hindu descriptions of Muni, Kesins and meditating ascetics, but these meditation-practices are not called yoga in these texts. The earliest known specific discussion of yoga in the Buddhist literature, as understood in modern context are from the later Buddhist Yogācāra and Theravada schools.
The earliest extant systematic account of yoga and a bridge from the earlier Vedic uses of the term is found in the Hindu Katha Upanisad (Ku), a scripture dating from about the third century BCE[…] [I]t describes the hierarchy of mind-body constituents—the senses, mind, intellect, etc.—that comprise the foundational categories of Sāmkhya philosophy, whose metaphysical system grounds the yoga of the Yogasutras, Bhagavad Gita, and other texts and schools (Ku3.10–11; 6.7–8).
^ Gavin Flood: "These renouncer traditions offered a new vision of the human condition which became incorporated, to some degree, into the worldview of the Brahman householder. The ideology of asceticism and renunciation seems, at first, discontinuous with the brahmanical ideology of the affirmation of social obligations and the performance of public and domestic rituals. Indeed, there has been some debate as to whether asceticism and its ideas of retributive action, reincarnation and spiritual liberation, might not have originated outside the orthodox vedic sphere, or even outside Aryan culture: that a divergent historical origin might account for the apparent contradiction within 'Hinduism' between the world affirmation of the householder and the world negation of the renouncer. However, this dichotomization is too simplistic, for continuities can undoubtedly be found between renunciation and vedic Brahmanism, while elements from non-Brahmanical, Sramana traditions also played an important part in the formation of the renunciate ideal. Indeed there are continuities between vedic Brahmanism and Buddhism, and it has been argued that the Buddha sought to return to the ideals of a vedic society which he saw as being eroded in his own day."
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:
Unintentional weight loss can occur because of an inadequately nutritious diet relative to a person's energy needs (generally called malnutrition). Disease processes, changes in metabolism, hormonal changes, medications or other treatments, disease- or treatment-related dietary changes, or reduced appetite associated with a disease or treatment can also cause unintentional weight loss. Poor nutrient utilization can lead to weight loss, and can be caused by fistulae in the gastrointestinal tract, diarrhea, drug-nutrient interaction, enzyme depletion and muscle atrophy.
In the first decade of the 21st century, the conceptualization of health as an ability opened the door for self-assessments to become the main indicators to judge the performance of efforts aimed at improving human health. It also created the opportunity for every person to feel healthy, even in the presence of multiple chronic diseases, or a terminal condition, and for the re-examination of determinants of health, away from the traditional approach that focuses on the reduction of the prevalence of diseases.
^ James Mallinson, "Sāktism and Hathayoga," 28 June 2012.
According to Pāṇini, the term yoga can be derived from either of two roots, yujir yoga (to yoke) or yuj samādhau ("to concentrate"). In the context of the Yoga Sutras of Patanjali, the root yuj samādhau (to concentrate) is considered by traditional commentators as the correct etymology. In accordance with Pāṇini, Vyasa who wrote the first commentary on the Yoga Sutras, states that yoga means samādhi (concentration).