Similarly, Brahma sutras – the foundational text of the Vedanta school of Hinduism, discusses yoga in its sutra 2.1.3, 2.1.223 and others.[121] Brahma sutras are estimated to have been complete in the surviving form sometime between 450 BCE to 200 CE,[122][123] and its sutras assert that yoga is a means to gain "subtlety of body" and other powers.[121] The Nyaya sutras – the foundational text of the Nyaya school, variously estimated to have been composed between the 6th-century BCE and 2nd-century CE,[124][125] discusses yoga in sutras 4.2.38–50. This ancient text of the Nyaya school includes a discussion of yogic ethics, dhyana (meditation), samadhi, and among other things remarks that debate and philosophy is a form of yoga.[126][127][128]
Continuing weight loss may deteriorate into wasting, a vaguely defined condition called cachexia.[30] Cachexia differs from starvation in part because it involves a systemic inflammatory response.[30] It is associated with poorer outcomes.[25][30][31] In the advanced stages of progressive disease, metabolism can change so that they lose weight even when they are getting what is normally regarded as adequate nutrition and the body cannot compensate. This leads to a condition called anorexia cachexia syndrome (ACS) and additional nutrition or supplementation is unlikely to help.[27] Symptoms of weight loss from ACS include severe weight loss from muscle rather than body fat, loss of appetite and feeling full after eating small amounts, nausea, anemia, weakness and fatigue.[27]
In 2008 between US$33 billion and $55 billion was spent annually in the US on weight-loss products and services, including medical procedures and pharmaceuticals, with weight-loss centers taking between 6 and 12 percent of total annual expenditure. Over $1.6 billion a year was spent on weight-loss supplements. About 70 percent of Americans' dieting attempts are of a self-help nature.[23][24]