I notice at my club:
Skinny but fit people on the machines, and doing the crossfitting-ish stuff.
Big muscle-bound people and women who could beat me up on the free weights.
Fat men and women on the stationary bikes, stair climber things, treadmills.
When I do see the fatter, bike/stair/treadmill people on the machines, they lift basically zero weight, and do about a million reps.
I noticed, myself, that simply running slowly all the time, no matter the mileage, didn't do much for my weight. ONLY once I began lifting (some time ago), and lifting fairly heavy did I get any degree of muscle toning, INCLUDING on my otherwise fit legs.
I'm a believer in high intensity, and heavy, and sprints, and little distance stuff, but understand this won't make me a world-beater. I does make me (overall) fitter, though, and I'm good with that (and with the lower weight/BMI I have now).