I am fairly certain I know the answer to this. They normally do these kind of studies on untrained humans, because the point is to prescribe (or not) exercise to people who need to lose weight, which are typically not athletes. The anecdotal success comes from people who play sports (tautologically). The problem is you cannot compare across these two groups because the metabolism and sheer volume of exercise is not comparable. Even a semi serious athlete will put in 5-6 hours of intense training a week. And their bodies are much more efficient, so they can burn way more calories in the same time. This is NOT the same as “Brisk walk and lift some weights 3-4 times a week” they prescribe the study group in a study of untrained athletes. Not even close.
I mean the typical advice I get is 1 hour of running burns as much calories as one large slice of pepperoni pizza (~700 cal). Trained or untrained, this seems off by a lot.
Why does it seem off? It's hard to measure calories when running, but with cycling we have power meters which are incredibly precise, and you will burn around 700 calories an hour (as a beginner). Trained athletes can burn maybe double of that.
