That’s because it showed that, on average, pretty much everyone burns the same amount of calories a day. That’s true even when comparing active versus sedentary people, because our metabolisms are very well set.

The conclusion came from spending time with the Tanzanian Hadza tribe, one of the last hunter-gatherer tribes in the world. “Hadza men and women get between five and 10 times more physical activity every day than many women in the US or Europe. They are incredibly physically active. If you’re a step counter, the Hadza people get about 13,000 to 19,000, steps a day. Plus they’re digging up tubers and they’re chopping into trees… and they’re carrying babies on their back. I mean, it’s a lot of work,” Dr Pontzer explains.

“We were sure going into that that they would be spending tons more calories every day than we do in the west. That was the whole premise of the work, to go and document the deficit that we seem to have in the west. And instead what we found was that their total energy expenditure, or total calories, spent per day is the same – indistinguishable from folks in the US and Europe.”

Exercising for calorie burn is pointless – here’s why we burn the same energy despite activity levels