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.
Because it burns off about a whole large pizza's worth, rather than one slice, and I'm not trained.