Maybe people already commented about this, but:
What just ocurred to me: Is James really the "worst" case of obesity we have seen? I mean we have had bedbound people before (Penny, Marla etc.), but they all could move at least a bit. They could sit up by themself, couldnt they? Or at least they could hold up their body once it was in a sitting position (and did`nt need 3 people propping them up). James K. really is total immobile as it seems. Probably does`nt have much functioning musclemass in his entire body. Although he claims he is getting "solid as a rock". Really laught at this totally absurd scene.