Did find a nice source about that math
https://www.tapatalk.com/groups/urwforum/a-little-disappointed-nutrition-t7400.htmlI think the issue comes down to frequency of eating, vitamins/minerals, and psychology.
The amount you can fit in your stomach per day doesn't change much in real life. If you're eating under your nutritional needs, even if you're physically filling your belly you'd still accumulate "starvation" as the game has. Trying to replicate this in game would probably make the system more obtuse than it already is. The simplified system makes being under nutritional requirement a real pain, which makes it worthwhile to starve rather than to eat bad foods from a player's convenience point of view.
Vitamins/minerals are not represented in game, nor is the game typically played in a time frame where they would matter. This element of eating leafy stuff in this sense isn't represented in game, despite many leafy things being edible and that being why we'd eat them.
Psychology is the last reason why humans eat some plants, because they taste good and make people happy. This is why many of our crops are cultivated. Psychology isn't majorily represented in game, with it tying only lightly to the spirit world.
I think the big reason that confused my nooby self is that there's no real good foods in the early months other than meat. Starting in spring or summer, your options are all not really worth eating with how the game represents nutrition (basically since we ignore vitamins). This gets compounded when villagers start selling turnips, which are a food basically in game for immersion and no real mechanical reason. It makes sense people like myself throw their hands up when even village vegetables suck. Faced with those stumbling blocks, I can see why I got frustrated and so do others even though good plant foods do exist in some instances.
There's also the issue that our cooking options don't really help us here. Soups make things less calorie dense, but because filling our hunger bar depends basically on how calorie dense our food is it's counterproductive. Even if you fill more now, you're damaging the amount you fill later. Also cooking foods doesn't (to my knowledge) liberate calories like it's thought to in real life either. And as mentioned, our character doesn't really care how it tastes. I think if our cooking options allowed us to make more calorie dense foods out of our low density vegetables it might help, but we'd quickly hit another roadblock of it being hilariously difficult to gather enough of those foods to actually make something out of them.
Thanks for taking time to reply