Most of us think of fat as a disgusting sign of overindulgence and lethargy. In some cases, it may well be. But new research shows that, far from being superfluous, body fat helps to protect bones and organs, regulates hormones and the immune system, and 'feeds' vital organs such as the heart and kidneys. It also produces an important hormone called leptin, which sends information about the body's energy levels to the brain.
According to British researcher Caroline Pond, mammalian fat is meticulously organised, grouped into about a dozen specific sites around the body. At each site, the fat's function is linked to its location - be it on the heart, or in muscle or lymph nodes (Pond C, The Fats of Life, Cambridge University Press, 1998). So complex and diverse are the functions of fat that some scientists believe that its status should now be upgraded to that of an organ.