Body temperature reflects metabolic rate (the amount of food burned per day per unit of body weight). Some advocates of natural life extension believe reducing an individual's core temperature and metabolic rate may assist longevity.
One such is Dr Roy Walford, Professor of Pathology at the University of California at Los Angeles, and author of several books on life extension, including The 120 Year Diet How to Double Your Vital Years (New York: Simon & Schuster, 1986) and The Anti Ageing Plan: Strategies for Extending Your Healthy Years (New York: Four Walls Eight Windows, 1994).Our core temperature is not determined by environmental factors directly, but depends on internal thermostatic controls, which probably lie deep in the brain (in the hypothalamus). Nonetheless, Walford believes there is a clear advantage in a pleasantly warm environment; cold conditions call both for greater metabolic activity and calorie intake, with all the negative results that this produces.
Ways to reduce core temperature include calorie restriction (Walford recommends a diet of 1,600 calories a day), but also meditation and similar techniques such as biofeedback.