Attacking Famine with food should produce some slight effect, like minimal damage, the food disintegrating, or possibly no more than a YAFM about Famine looking offended.
Eating healthy foods (fruits, vegetables, royal jelly?) should exercise Constitution, and eating unhealthy foods (candy bar, cream pie, etc) should abuse it.
Celery, a comestible which uniquely has negative nutrition (because in real life, it takes a human body more calories to digest the celery than are in the celery.) The main use of this negative nutrition is to unsatiate yourself so you can continue eating other food.
It should be a large amount of negative nutrition in order to be worthwhile, but at the same time shouldn’t be instadeath for unsuspecting new players by immediately starving them. To that end, special case it so that it does not harm you if you are Hungry or worse, is worth -30 nutrition if “not hungry”, and is worth more negative nutrition if Satiated, possibly scaling up the more satiated you are.
Depending on implemenetation, it could either be safe or unsafe to eat when oversatiated - realism dictates it should be unsafe to eat, but gameplay dictates it would be useful in fewer situations unless it is always safe to eat. Or have it count as a small positive nutritional value assessed before maybe choking, followed by a large negative nutritional value assessed after you didn’t choke.
Knights still incur alignment penalties for eating celery while satiated.
The celery also crunches loudly whenever eating it, so it wakes up nearby sleeping monsters.
Everlasting gobstopper, a food item that you start sucking on when you eat it, providing a constant d2 nutrition per turn. It never gets used up, but once you spit it out (by choosing to eat something else or by using “-“ with the eat command) it is no good anymore and gets used up. If you get oversatiated by not spitting it out, you can indeed choke and die on it.
Fast food shop, a type of comestible-containing shop in which no vegan food generates. All the food that does generate in the shop has a special flag set so that it is guaranteed to satiate you (or at least have its nutrition multiplied), gives you greasy fingers, and costs more than usual.
Leprechauns very rarely drop a four-leaf clover on death. This is a vegan comestible that provides 1d3 luck (or just acts as a luckstone) when carried and can be eaten to gain 1 Luck. (The four-leaf clover appearing from sacrifices is not this item and cannot be picked up, though that could become confusing.)
Collection of vague ideas around a new “chef” role:
Easter egg: a comestible that has very low weight and very high nutrition, thus a very good food to have. They generate very rarely, perhaps only 1-3 per game on average, and generate exclusively in hidden spots: in chests, closets, and vaults, the dead ends of mazes, beneath sinks (revealed when you step onto the sink), in trees (revealed either when you step next to the tree or kick it), etc. The glyph is brightly colored, perhaps purple.
All food generated in Gehennom (including both food generated with the level and after creation time, and corpses) is rotten.
If a boulder rolls over certain types of comestible, it becomes a pancake. (Which types of comestible isn’t specified; probably it should not be possible to turn corpses, tins, or lower-nutrition-than-pancake permafood into pancakes.)
Containers never generate with food. Instead, split up the probability of food among other object classes that have nonzero probability, and also allow some tools to generate in them.
Perfectly fine uncursed food should not make the hero pass out.
Jars, which are like tins except made of glass (or possibly, tins made of glass material, in object materials implementing variants). Generate quite often as chest contents. Possibly, what is in the jar is apparent just by looking at it.
Tomatoes, a type of comestible that you can throw at monsters to decrease their charisma (if they had charisma).
Lemons, a comestible that deals 1 point of damage when eaten unless acid resistant and exercises Constitution. If you are killed by eating a lemon, the death reason is “killed by citric acid”.
Most d and f monsters can be pacified, but not tamed, by throwing appropriate food at them (they will eat it, so you can’t reuse the same food item).
Any comestibles death-dropped by an F monster are rotten when eaten.
Gillyweed: comestible that grants temporary intrinsic magical breathing when eaten.
