"... The upshot is that “there is no effect of economic development on size-adjusted physical activity expenditure,” Pontzer says. In which case, the fundamental problem isn’t that we’re moving too little, meaning more exercise is unlikely to reduce obesity much.
What could, then? “Our analyses suggest that increased energy intake has been roughly 10 times more important than declining total energy expenditure in driving the modern obesity crisis,” the study authors write.
In other words, we’re eating too much. We may also be eating the wrong kinds of foods, the study also suggests. In a sub-analysis of the diets of some of the groups from both highly and less-developed nations, the scientists found a strong correlation between the percentage of daily diets that consists of “ultra-processed foods” — which the study’s authors define as “industrial formulations of five or more ingredients” — and higher body-fat percentages.
We are, to be blunt, eating too much and probably eating too much of the wrong foods. ... The findings don’t mean, though, that exercise is unimportant ..."