Ulijaszek S J
Department of Biological Anthropology, University of Cambridge.
J Biosoc Sci. 1993 Jan;25(1):79-86. doi: 10.1017/s0021932000020320.
The consequences of different birth intervals on dietary energy requirements and dependency ratios at different stages of the family lifecycle are modelled for Gambian agriculturalists and !Kung hunter-gatherers. Energy requirements reach a peak at between 20 and 30 years after starting a family for the Gambians, and between 15 and 20 years for the !Kung. For the Gambians, shorter birth interval confers no economic advantage over the traditional birth interval of 30 months. For the !Kung, the lack of participation in subsistence activities by children gives an output:input ratio in excess of that reported in other studies, suggesting that they are in a state of chronic energy deficiency.
针对冈比亚的农民和昆族狩猎采集者，模拟了不同生育间隔对家庭生命周期不同阶段饮食能量需求和抚养比的影响。对于冈比亚人来说，组建家庭后能量需求在20至30岁之间达到峰值，而对于昆族来说则是在15至20岁之间。对于冈比亚人而言，较短的生育间隔与传统的30个月生育间隔相比没有经济优势。对于昆族，儿童不参与维持生计活动导致产出与投入之比超过其他研究报告的水平，这表明他们处于慢性能量缺乏状态。
