I have know about 3 people who have trained for a marathon.
One person was doing it to "finish" and had a completion time of ~8 hours and explained that if all you cared about was crossing the finish line for a bucket list item, you start in the last group, wait about 10 minutes after the official start time of you group for the pack to thin, and then just start walking. If you are just wanting to haul your ass 26.2 miles and are more in shape than DSP, it is 100% mental. You just have to keep drinking electrolytes and force your to body to keep putting one foot in front of the other. The only prep work you really need to do is make sure your shoes are not rubbing anywhere on anything. Other than that the only reason you can't complete a marathon is you are mentally weak.
(I think they were nuts and understating things, but they say they've done this for several cities and also claim they got some 60 year old guy who had never run before across the finish line by drill-sergeanting him and refusing to let him give up.)
I knew another person who was not exactly competing to win, but was trying to get a respectable time by actually running a marathon. He was far, far from out of shape before starting, but they trained for about a year, with two ~three-month periods of being extremely serious about it (a initial training peroid, a healing period for maintenance, a second training peroid, and then recovery before the event). During the "serious" periods they were eating 6,000-9,000 calories every day and had tons of unexpected ancillary problems - but the calories are what always stuck with me becasue he described the diet as "great for the first week, and then hell. My wife was dumping (cooked) chicken breast and heavy cream into a blender with protein powder at 9pm to make the most disgusting smoothies because i needed more protein & fat that day and was too tired to chew." And again, he played competitive weekend-league sports and when he was done said he wasn't doing that again.
And I know one person who started, and then decided after a month or two that marathons were for suckers and settled for going for a 13.1 sticker. They didn't say if they were making chicken breast smoothies or not, but he had also talked about the obscene amounts of food you'd eat getting calories stocked to run your trial 26.2 on the treadmill.
We've seen the disgusting slop John makes. A hello fresh meal contains like 1/10th the calories someone training for a marathon needs. Maybe he's sneaking some slices of his gumbo on the side, but from what other people have told me there is zero chance John is getting the calories do what he he's doing and have the gunt he does.
