Metabolic Cost of Living in Human Foragers

许多关于人类生态学和生理学的长期假设推测了前农业社会对人类的能量需求，但狩猎采集者的能量使用从未被直接测量过。 在这个项目中，将测量哈扎人成年男女的每日能量消耗，他们生活在坦桑尼亚北方的萨凡纳草原和开阔林地栖息地，靠狩猎和采集野生食物为生。 能源使用数据将与活动数据和人口统计信息进行比较，以了解农业出现前社会对人类的能源需求。 这项研究将是第一个测量人类狩猎采集者每日能量消耗的研究。使用双标记水方法，每日能量消耗（即，每天消耗的卡路里）将在两周内进行测量。 体重、去脂体重、年龄以及受抚养者的数量和年龄（例如，将记录每个受试者的代谢率（儿童），以及静息代谢率和步行的能量消耗。 在两周的能量测量期间，还将记录每例受试者的心率和每日活动预算，包括每天步行的距离以及觅食和休息所花费的时间。 总之，这些数据将用于确定人类觅食者的每日能量预算，以及用于各种活动（包括休息代谢和旅行）的每日能量预算比例。 然后比较受试者的每日能量预算，以确定性别、年龄和受抚养者人数对每日能量消耗的影响。 这些数据将被用来测试和告知有关在前农业社会对人类的能量和生理需求的假设。一名研究生和两名坦桑尼亚研究助理将通过参与该项目获得重要的研究经验。 研究结果将纳入华盛顿大学的课程。

Many longstanding hypotheses regarding human ecology and physiology speculate about the energetic demands placed on people in pre-agricultural societies, but energy use in hunter-gatherers has never been measured directly. In this project, daily energy expenditure will be measured for adult men and women of the Hadza, who live in savannah and open woodland habitat in northern Tanzania subsisting on wild foods which they hunt and gather. Energy use data will be compared to activity data and demographic information in order to understand the energetic demands placed on humans in pre-agricultural societies. This study will be the first to measure daily energy expenditure in human hunter-gatherers.Using the doubly-labeled water method, daily energy expenditure (i.e., calories used per day) will be measured over a two-week period. Body mass, fat-free mass, age, and the number and ages of dependents (e.g., children) will be recorded for each subject, as will resting metabolic rate and the energy cost of walking. During the two-week energy measurement period, heart rates and daily activity budgets, including the distance walked each day, and the time spent foraging and resting, will also be recorded for each subject,. Together, these data will be used to establish the daily energy budget for human foragers, as well as the proportion of the daily energy budget spent on various activities including resting metabolism and travel. Daily energy budgets will then be compared among subjects to determine the effects of gender, age, and number of dependents on daily energy expenditure. These data will be used to test and inform hypotheses regarding the energetic and physiological demands on humans in pre-agricultural societies. A graduate student and two Tanzanian researcher assistants will earn important research experience through their involvement with this project. Results will be incorporated into the curriculum at Washington University.