@T3hPwnisher just moving over here to not clog @unicornsandrainbows journal.
That got my brain thinking. If you say the average 600lb person has 400lbs fat mass, that’s over 181000 grams of fat, if that’s 9 cals of stored energy, that’s over 1.6m calories, Google tells me that the average marathon burns 2.5-3.5k cals, allowing for a larger person to be the top end and ignoring any adaptations, that means a 600lb person could run 465 marathons, without eating!
(If my extremely rough maths is anywhere near correct, and yes for any pendants - I’m aware that 600lb people aren’t going to be able to run a single marathon).