Imagine this scene – a personal trainer barking at his flabby pen-pushing charges to push themselves through the pain barrier and climb those steps because “the human body wasn’t designed to sit at a computer all day”. It’s easy to imagine because of the common perception that the root cause of the current obesity epidemic is a radical shift in human behaviour – from the hunter-gatherer ways of our ancient ancestors to our current sedentary lifestyles with diets high in energy-dense and highly-processed foods.
But, in a paper just published in PLoS One researchers from the United States, Tanzania and England have shown that there’s actually no difference in the energy expenditure of the modern American in comparison to the closest modern comparator we have to the hunter-gatherer lifestyle, the Hadza foragers of Northern Tanzania.
According to the authors, although the hunter-gatherers do indeed walk far more than your average American, they actually expend the same amount of total energy. Based on these findings, the authors challenge the view that obesity in Western populations results from decreased energy expenditure, placing the blame squarely on our high-energy diets.