In the series, they describe him as being overweight due to his very, very poor diet. There's even a joke about how he ruins Simmons' old body parts with said diet (Beer, smoking, junk food, etc). Honestly, if you ate junk food, smoked, drank beer and never really exercised, I'm sure you'd have a gut too.
I like the camera angles in each panal, showing in a funny way like a real cartoon. And the way Grif and Simmons are represented here sort of reminds me of Laurel and Hardy, only they talk more. Great rendition of the first episode.
Exceptional as always, Mr. McKay. Lol, Simmons looks kind of bobblehead-like to me, exactly how I imagined him. XD Great homage to the question that started such an epic series. Hope you can do more of these.