WACO, Texas — The coronavirus pandemic is keeping many children inside, adding to the perception that Americans kids don’t get enough exercise. Despite a more sedentary lifestyle, a study finds children from remote Amazonian tribes burn just as many calories as the average American youngster. According to Baylor University, this challenges current theories about the causes of obesity — saying the problem is likely a poor diet and not poor fitness.
Researchers say the forager-horticulturalist children in this study burnt their calories in many different ways than American children. Forty-four Shuar children, between the ages of five and 12, were compared to data on industrialized children in the U.S. and United Kingdom.
About 50,000 Shuar people live in the isolated Amazon region of Ecuador. They don’t have easy access to grocery stores and labor-saving technology. They subsist on fishing, hunting, foraging, and small-scale agriculture. The Baylor team gathered energetics data by using isotope-tracking and respirometry collection methods. It’s the first time this type of energetics data measurement is being used on a subsistence-based population.
What’s different about children in the Amazon?
Their results reveal that, despite Shuar children being about 25 percent more physically active, the total number of calories spent every day is indistinguishable from Americans children. Shuar children also have a 20 percent greater resting energy expenditure, mostly because of higher immune system activity.
“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 U.S. and elsewhere,” study author Dr. Samuel Urlacher says in a university release. “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 U.S.”
The current models on human nutrition assume that exercising more and doing anything that increases your metabolism forces you to expend more energy. This in turn makes you burn more calories. The study suggests that children in industrialized countries are simply taking in too much food because they’re burning off the same amounts as their peers in the Amazon.
“This similarity in energy expenditure suggests that the human body can flexibly balance energy budgets in different contexts,” the assistant professor at Baylor adds. “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.”
Limitations in childhood can lead to obesity, diabetes
The new studies show that total energy expenditure is actually constrained during childhood. The Baylor study sought, for the first time, to compare these two opposing nutritional models.
Study authors believe that the negative tradeoff of this constraint results in limiting physical growth in children. Researchers add looking at this constraint could help them understand the relationship between childhood growth stunting and its link to adult obesity and type 2 diabetes.
The report also shows that a higher degree of physical and immune activity may reduce energy needed for growth, even when plenty of food is available. Therefore, the researchers argue, diet, not energy expenditure, is causing chronic weight gain and the global obesity epidemic.
The study was published in the journal Science Advances.