Have you guys heard of Dr. Herman Pontzer and his intriguing research concerning human metabolism? He's a biological anthropologist at Duke University. I read his provocatively titled book
Burn: New Research Blows the Lid Off How We Really Burn Calories, Stay Healthy, and Lose Weight, and while I'm not sure how settled the science is it really blew my mind. Super provocative statements made by researchers should be considered very carefully ofc.
A 2012 study he did using the doubly-labeled water method of measuring metabolic expenditure (the gold standard) of a group of tribal hunter-gatherers and then comparing the data with previous findings of Westerners with a variety of lifestyles indicated there may be no significant differences in the metabolic expenditure of these groups:
https://journals.plos.org/plosone/ar...l.pone.0040503
It's been a couple years since I read the study, but some of the data didn't quite support the hypothesis and I think they try to explain why that might be. Since the publication, he's continued to perform studies that do keep pointing to this possibly being the case.
Basically, what Pontzer believes is that total metabolic expenditure is not significantly impacted by physical activity- meaning that while exercise is beneficial for a number of reasons, it will not result in loss of adiposity due to "burning more kilocalories". Exercise may result in weight loss for other reasons, such as reduced opportunity to consume kcal while exercising and physical activity making a person more health-conscious overall, but he does not believe that exercise = burning more total kcal.
One hypothesis is that when we expend kcal on physical activity, our bodies become more metabolically "efficient," and expend fewer kcal on other metabolic processes- which may be part of why physical exercise is so health-promoting.
Take all of this with a grain of salt ofc, but this is so fascinating and it's the sorta thing I nerd out hard over.