>>>>"Of course, if we push our bodies hard enough, we can increase our energy expenditure, at least in the short term. But our bodies are complex, dynamic machines, shaped over millions of years of evolution in environments where resources were usually limited; our bodies adapt to our daily routines and find ways to keep overall energy expenditure in check."
And yet how do we get from a modern man spending most of time sitting down spending the same energy as a Hadza walking ~100 miles a week to a modern Olympian swimmer supposedly spending 12,000 a day and maintaining 8-10% body fat while swimming 50 miles a week? Does 10+ years qualifiy as 'short term'?