Why aren't writers skinny?

Okay, I get the fact that we don't move around much, being as most of us sit at a computer for anywhere from 2-12 hours a day. I know I've clocked in more on occasion. But, if you are anything like me, you hardly eat.
                                                        

Anyone else hear the song in their head?

For instance, I'm sitting here writing this blog, starving, and I keep telling myself  'I'll eat after ___', fill in the blank. Right now, I'll eat after I finish with this blog entry. Before that, it was 'I'll eat after I finish answering some emails.'

No, I'm not starving myself, but like so many others, my diet consists of whatever I can pop into my mouth while not losing any momentum on the keyboard. I've eaten bites of salad between paragraphs, grapes get popped into my mouth while typing one-handed, or a banana gets shoved into my mouth...whole. Trust me, my daytime eating habits are not something you want to witness.

Oh, don't look at me like that; you know you do it, too.

So, again I ask - Why aren't writers skinny?

I've heard theories about the writers spread; you know, the same things office workers supposedly get. You sit too much and the derriere takes on its own zip code.

*sigh* Anyone know of a way to virtually workout while writing?