High prevalence of excess fat and central fat patterning among Mongolian pastoral nomads.

This paper presents information on body size, body composition, and fat patterning in a sample of 750 pastoral nomads aged 5 to 84 years, native residents of Moost district, Mongolia and evaluates the results from the perspective of morphological adaptation to a cold climate. Mongolian nomad men and children have average BMIs close to the U.S. 25th percentile while women have average BMIs close to the U.S. reference median. The prevalence of excess fatness assessed by the Arm Fat Index rises from 5 to 15% during childhood to 65% or more in each adult age-sex group except women 70+ years. The pattern of fat deposition is markedly central (abdominal) among women and children while it is normally so among men: women and children have a very high ratio of waist-to-hip circumference and children have a moderately high ratio of subscapular-to-triceps skinfold compared with other populations. A body composition favoring centrally deposited fat may be adaptive to a cold stressed population because it would aid in heat production (abdominal fat is thermogenic) and heat conservation (more spherical body size and better insulation) in the age-sex groups that are usually at a thermal disadvantage because of small body size and/or low basal metabolic rate relative to men. © 1992 Wiley-Liss, Inc.