Are you saying that whole grains are a reason some people are getting fat due to carb intolerance?
I think people are getting fat for a few reasons listed below
They are mentally unable to exercise
They are physically unable to exercise
They are excuse whores who choose not to exercise
They are just purely not into it
They exercise for the wrong reasons and quit to early
Now eating the wrong foods can definitely have an impact on ability but that's where they just need to change things up a little in their intake. It doesn't even take that much of a dramatic change either.