The Shuar community
is indigenous people of Ecuador and Peru in South
America, consisting of around 50,000 individuals. They belong to the Jivaroan
clan, who live in the tropical Amazonian rainforests. They
primarily live off the land through hunting, fishing, foraging, and subsistence
farming, including small-scale horticulture.
, was led by Dr.
Samuel S. Urlacher, PhD, who is an Assistant Professor of Anthropology at
Baylor University, Waco, Texas, USA. He is also the Co-Director of the Shuar
Health and Life History Project and has spent more than two years living with
the Shuar community in the Amazon.
Dr. Herman Pontzer,
PhD, who is an Associate Professor of Evolutionary Anthropology at Duke
University's Trinity College of Arts & Sciences, was a study collaborator
and co-author. Other study collaborators were from the University of Oregon,
Northern Arizona University, and Loyola University, USA.
Uniqueness of the Study
Conventional human nutrition models have all along assumed
that daily energy expenditure arising from exercising and other metabolic
functions have an additive effect, leading to increased burning of the total
number of calories
However, a new model, based on recent studies that have consistently shown that
the original model is faulty, as the daily total energy expenditure of the
human body is limited to a very narrow range. The uniqueness of the present
study is that it is the first study to actually test these two opposite models
of energy expenditure among children living in harsh conditions.
Key Features of the Study
- 44 forager-horticulturist Shuar children aged
between 5 to 12 years were included in the study
- Energy expenditure data was collected from the
Shuar children and compared to data of children from strong economic
countries such as USA and UK
- Energy expenditure was measured by isotope-tracking
and respirometry techniques - both Gold Standards
- This is the first study to use these
state-of-the-art techniques in children from a subsistence-based
- The energy expenditure data was coupled to data on
growth, nutrition, physical activity, and immunity of the study population
Key Findings of the Study
- Shuar children were 25 percent more physically
active than US and UK children
- Shuar children had 20 percent higher resting
energy expenditure than US and UK children, due to increased
- Total calories burned daily by Shuar children was the same as that of US and UK children, despite wide
differences in lifestyle and quality of food consumed
Pontzer explains: "These findings
advance previous work among adults, showing that energy expenditure is also
constrained during childhood."
Implications of the Study
The study findings
imply that energy constraints could be the underlying reason for reduced
childhood growth and elevated risk of developing obesity and metabolic diseases
such as Type 2 diabetes
and hypertension (high blood
during adulthood. Moreover, increased physical and immune
activity could limit the amount of energy required for growth, despite the unlimited availability of food.
The research team plans to improve the
study design in the following ways:
- Inclusion of children of a wider age range
- Comparison of the data generated with additional study
- Collection of longitudinal data on lifestyle and
economic status within a single population
- Application of the research findings to improve the
health of the Shuar community and other populations across the globe
Urlacher indicates: "Conventional
wisdom suggests that an increasingly sedentary and germ-free lifestyle,
resulting in low daily energy expenditure, is a primary factor underlying
rising rates of obesity in the US and elsewhere."
He adds: "The findings of our study challenge that
notion. We demonstrate that Amazonian children with
physically active lifestyles and chronic immunological challenges
don't actually burn more calories than much more sedentary children living here
in the US."
"This similarity in
energy expenditure suggests that the human body can flexibly balance energy
budgets in different contexts,"
says Urlacher. "Ultimately, eating too much, not moving too little, may be at the core of long-term weight gain and the global nutrition transition that
often begins during childhood."
He concludes: "The science is exciting, but, ultimately,
we hope that our research can help to improve health among the Shuar, in the US
The study was
funded by the National Science Foundation, Alexandria, Virginia, USA.
- Eating Too Much Not Exercising Too Little May Be at Core of Weight Gain, Study of Amazonian Children Finds - (https://www.baylor.edu/mediacommunications/news.php?action=story&story=215728)