So as is, its pretty neat, but there are a good couple of issues that I think hold it back.
My main issue is that this game is RNG as FUCK. Every eating challenge seems random, which takes any interest in them away aside from just making the MC bigger. The inflation thing to increase capacity is basically a coinflip from what I've done of it, to the point I just don't bother after a certain point because it sucks shit to lose a bunch of progress to said coinflip. And as for the pill guy, the fact that it always takes all of your money is kinda lame as it basically makes the next challenge you choose an all or nothing situation. Plus, not really knowing how your capacity/digestion stats look makes any risk feel very vibes based. Maybe its just because I never grew up playing/even played Oregon Trail, but having these events be coinflips, and one of them being a game over if you are just unlucky, feels super not fun.
There's also the variety of events. There's really only three IIRC, the pill dealer, the inflation one, and any eating challenge. Outside of that, there really isn't anything else to do, not even a real end point. I wish there were some other events, like maybe meeting someone else who's doing the same trip, or having to upgrade your car to accommodate your weight, or helping to squeeze another contestant out a door frame, or maybe some flavor text while driving depending on your weight. Maybe some endings, like if you take too many of the dealers pills, you become a dealer or something yourself, or if you do the inflation event too many times successfully, you become an ad balloon for a restaurant. I think it just needs some more things to really make it feel fleshed out.
I got some other small issues, but they aren't really major. I kinda wish the model fattened up more around the arms and face to match her torso, the lack of that sorta threw me off. I also wish it had some audio, music or sfx, either or.
Overall, the game itself is neat, but I do think it's a bit too barebones as is. I'd probably say a 6/10, leaning more towards a 7.