They might be. But even if they are it's a pretty good sign of failure. Changing eating habits around is a pretty big thing. Even more so when we're talking about people in the higher overweight or obese range. They're typically going to need to totally rethink their entire idea about what food even is or what it's for. It's a huge deal and something that you'd have to be wrong about for many years or even decades to reach where they are.  Exercise is also a pretty huge change to someone's lifestyle and will require a lot of work. Someone who's been consistently failing on both to such a huge extent is setting themselves up for failure by trying to do both at the same time. Not to mention that the exercise, for a lot of people, will increase overall hunger even more. Which is something that they had trouble dealing with even without the additional physical stress. Then there's the problems of the fact that they're doing workouts with a huge amount of extra weight everywhere. Jogging, for example, with more than a hundred pounds of fat bearing down on one's joints is a terrible idea.  Sure, some people do go from obese to fit using a combination of diet and exercise at the same time. But the vast majority of people who try to fix two huge problems in their life at the same time aren't going to succeed. And even all that's giving them a little too much credit, in my opinion. What's far more common is for exercise to be used INSTEAD of dealing with the most important issue. Which is their diet. Exercise is usually just a flimsy defence mechanism used to deflect attention away from the area they really don't want to confront. A fat person trying to exercise and eat right for the first time is probably going to fail. A fat person who's trying to do it all with exercise certainly will. The only good chance a fat person has is by first fixing their diet and getting into the upper end of the healthy weight range. That's the point where exercise starts to become a useful option for burning off the extra pounds while also improving overall health.