Metabolic Cost of Living in Human Foragers

许多关于人类生态和生理学的长期假说推测了前农业社会对人们的能量需求，但狩猎-采集者的能源消耗从未被直接测量过。在这个项目中，将测量哈扎族成年男女的日常能源消耗，他们生活在坦桑尼亚北部的大草原和开阔的林地栖息地，以他们狩猎和采集的野生食物为生。能源使用数据将与活动数据和人口信息进行比较，以了解前农业社会对人类的能源需求。这项研究将首次测量人类狩猎-采集者的日常能量消耗。使用双重标记水法，将在两周的时间内测量每日能量消耗(即每天消耗的卡路里)。将记录每个受试者的体重、脱脂体重、年龄、家属(例如儿童)的数量和年龄，以及静息代谢率和步行的能量成本。在为期两周的能量测量期间，每个受试者的心率和日常活动预算，包括每天步行的距离，以及觅食和休息的时间，也将被记录下来。这些数据将一起用于建立人类觅食者的每日能量预算，以及用于各种活动(包括休息新陈代谢和旅行)的每日能量预算的比例。然后，将在不同受试者之间比较每日能量预算，以确定性别、年龄和家属数量对每日能量消耗的影响。这些数据将被用来测试和提供有关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员助理将通过参与该项目获得重要的研究经验。结果将被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.