"You can't outrun your fork" is an old saying I've heard from fitness types, and for fatties it's true. Most exercise they do in an attempt to burn off calories (almost always cardio) doesn't actually burn very many calories--not enough to create a deficit when you've got an average-height woman at a sedentary job who shovels in 2500+ calories every damned day. And, more often than not, fatties use having gone to the gym as an excuse to indulge themselves with some high-calorie favorite treat, thus completely negating however many calories they burned.
If they lack the will to simply eat less, or to clean up their diets (so they aren't eating shit that spikes their blood sugar and leaves them hungry and craving all the time, and/or provokes an inflammatory response that keeps them feeling generally crappy and lethargic), where are they going to find the inner discipline and motivation to hit the gym--or even go for a fucking walk every evening? Especially when just hauling your fat body around for normal daily activities is exhausting?
The core problem for any fat person is diet--quality as well as quantity. Until they address that and clean up their act, going to the gym is, at best, pointless and unpleasant. And the larger and heavier they are, the more likely going to the gym is to be counterproductive. Their joints are constantly stressed past their limits, and having lots of blubber in the way means they can't use proper form, which sets them up for injury.
