PHYSICAL-ACTIVITY, ENERGY STORES, AND SEASONAL ENERGY-BALANCE AMONG MEN AND WOMEN IN NEPALI HOUSEHOLDS

The relationships among initial energy stores (body mass index), energ y turnover (physical activity levels), and seasonal energy balance (we ight changes) were examined in subsistence agropastoralists in rural N epal. The population experiences no actual food shortage, but has a se asonal increase in physical activity levels, which are moderately heav y in early winter and very heavy in the monsoon season [men, 1.88 and 2.22 x basal metabolic rate (BMR); women, 1.77 and 2.01 x BMR in the r espective seasons]. Repeated anthropometry in 1982 (29 men and 34 wome n), 1983 (29 men and 29 women), 1991 (22 men and 48 women), and 1993 ( 48 men and 72 women) showed a consistent interannual pattern of signif icant but modest seasonal weight change (<4% of initial values) and re markable interindividual variation (men, -5.6 to 5.6 kg; women, -5.6 t o 4.8 kg). Thinner individuals showed no significant change in body we ight or workloads, and sustained high levels of total energy expenditu re throughout the year. Heavier individuals lost weight (men -2.7 kg, women -0.9 kg) and increased total energy expenditure by 23% over the same period. Elements of lifestyle, especially during the season of le ss constraining workloads, allow for the continuation of hard work or taking a respite for nutritional recovery. The nature of household lab or organization, featuring a highly flexible distribution of tasks, al so contributes to the relatively short-term, reversible changes in ene rgy balance in this population. (C) 1996 Wiley-Liss, Inc.