Originally Posted by Whiteroom
Beyond, read your own citations and then get back to us about how a well supported foot in a plastic ski boot will see a large change in size due to 10% loss of body weight.
Actually, I have; fairly certain you haven't, unless you've paid for access to the journals. A 10% loss of body weight should be reflected in a corresponding loss of of fat and muscle tissue around the perimeter of the foot, especially the heel and ankle, reductions in fluid infiltration, and less loading on the arch, which impact three dimensions. Will that equal a change of a boot size? Well, one of the studies shows a change of 15% in street shoe size between normal and overweight. Overweight means 120% of average. So extrapolating, a difference of 10% body weight would produce about a 7.5% difference in shoe size, primarily because of changes in foot width. Rough calculation since the variables are not linear to each other. But that's a bit under one shoe size if you start at men's 10.
Anyway, would this require any change in shell size? Don't know, that's your department. Will that produce a subjective difference in how the guy feels in his boots? Well, seems like unless our chants about snug fit are b.s., it might. Does he need new boots? Again, not my department, would guess markojp is probably on the right track. Odds are anything OP's feeling is at least compounded by boot fit. Sometimes outcomes can have more than one cause. Could be foot size change and boots that were too big to begin with. Or not.
Look, this is not about me challenging your or SJ's ability to fit boots. From my first post, it's been about me correcting some simple misinformation. OP's or anyone else's feet do change when he loses or gains weight, because feet do have muscle and fat, and and it's not inert, but metabolically as active as any other fat on your body.
Footnote: This may have started by telling posters they're wrong about their own bodies. For instance, as a guy who's not shy about calling people "sexist" for their pronoun choices, I'm sure you get the ramifications of telling your next female customer who walks in after having a baby, or losing some weight in the past few years, that sorry, but she's mistaken; her feet really haven't changed. Naw, I wouldn't go there either. Especially when the science backs her.