‘Hunter-gatherers, modern men use same energy levels’

July 26th, 2012 - 6:22 pm ICT by IANS  

Washington, July 26 (IANS) Surprisingly, hunter gatherers and their current day counterparts expend the same energy levels, says a new finding, upsetting one of the most entrenched popular notions that modern lifestyle is to blame for the current rise in global obesity.

Researchers suggest that the similarity in daily energy expenditure across a broad range of lifestyles suggests that habitual metabolic rates are relatively constant among human populations. This, in turn, supports the view that the current rise in obesity is due to increased food consumption, not decreased energy expenditure.

The research team, led by Herman Pontzer of Hunter College in New York City, along with David Raichlen of the University of Arizona and Brian M. Wood of Stanford measured daily energy expenditure (calories a day) among the Hadza, a population of traditional hunter-gatherers living in the open savannah of northern Tanzania, the journal Public Library of Science ONE reports.

Despite spending their days trekking long distances to forage for wild plants and game, the Hadza burned no more calories each day than adults in the US and Europe, according to a Hunter College statement.

“These results highlight the complexity of energy expenditure. It’s not simply a function of physical activity,” says Pontzer. “Our metabolic rates may be more a reflection of our shared evolutionary past than our diverse modern lifestyles.”

The team ran several analyses accounting for the effects of body weight, body fat percentage, age, and gender. In all analyses, daily energy expenditure among the Hadza hunter-gatherers was indistinguishable from that of Westerners.

The study was the first to measure energy expenditure in hunter-gatherers directly, previous studies had relied entirely on estimates.

The authors emphasise that physical exercise is nonetheless important for maintaining good health. In fact, the Hadza spend a greater percentage of their daily energy budget on physical activity than Westerners do, which may contribute to the health and vitality evident among older Hadza.

Still, the similarity in daily energy expenditure between Hadza hunter-gatherers and Westerners suggests that we have more to learn about human physiology and health, particularly in non-Western settings.

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