The question is, how much it would add to the game to justify the development time.
For the "normal in-bubble gameplay" (which I guess is what the majority of players do), the benefits would be non-existing. What is there to gain from food consumption, if you dock at stations every other minute anyway and food (and water) supplys can be restored easily?
But let's imagine, it is implemented nevertheless. What impact could (different) food have on the game? Our skills are determined by ower own real-world capabilities. If you want better reaction times, don't drink booze while flying. And I certainly don't want unresponsive inputs due to ingame starving.
Maybe visual effects could be affected, such as the already existing readouts and blackouts. But those are not really related to food, but to physical high-g effects. Maybe some sort of tunnel vision?
Where food and water would come into play would be exploring and I like the general idea of "expedition planning". How much provisions do I need for my planned three month trip? There even could be a cost/benefit evaluation of provition weigth vs. jump range.
But again: what would be the related interesting game mechanics? Worsened vision can not be all. ED is not a surviving game, where finding enough food is a crucial part of game play. And current long-time explorers definitely wouldn't love an artificial limitation of their month-lasting trips - especially without benefits for their gameplay.
Maybe on day, when landing on life bearing planets is possible, finding food sources might be interesting. But certainly not now.
Thinking about it...
water supply could be a relevant necessity already! With the introduction of ice mining, refilling your drinkwater is possible far away from civilization. Ice rings are incredible beautiful places and interrupting long exploration trips every now and then in order to mine for some time might actually add to the enjoyment. Outfitting a small mining laser and the smallest of all possible refineries might be a small enough requirement for extended expeditions.
However, a gamemechanic like this is already in place!
Exploreres usually do outfit a AFMU for a good reason. It has "provisions" that get consumed, and with synthesis, there is already a benefit of mining (and SRV driving) in order to refill consumed charges.
So, for explorers, the AFMU is factually a food game mechanic. And "starving" means a sad end for careless explorers already.
