Here is an odd situation. Our party is in a highly trapped dungeon and, based on the DMs request we record food and water before entering, are highly concerned we may get trapped for a month or two in magical traps.
If this were to happen, our chances are slim as we have no cleric that can create food and no summoning spells to create something we could kill or eat.
Is there any evidence anywhere of whether the Grease spell or Web spell creates anything edible?
In 5e, Spells do what they say do, and Grease does not say that you can eat it for sustenance (like Goodberry or Create Food and Water).
This doesn't mean that a DM couldn't make a house rule that they can be used for sustenance, but nourishment as a spell effect that isn't stated is not RAW. A DM can always allow for creative use for spells, but beware the slippery slope.
If your DM is wanting you to have to manage food, they may be unlikely to house rule in such a way because it minimizes the 'game' they are introducing to your table. If you can easily bypass the finding and management of food in this way, the DM could just have easily have hand waived a number of other things or simply not made food management a resource issue.
And don't forget about your need for water as well!
The web spell creates...
a mass of thick, sticky webbing at a point of your choice within range.
Sticky webbing is not edible (although it might be used to trap some insects which would be.
The grease spell, on the other hand, creates...
Slick grease [which] covers the ground in a 10-foot square centered on a point within range and turns it into difficult terrain for the duration.
Grease is "oily or fatty matter" so there is some hope.
Unfortunately, it is unclear whether the grease created is fatty grease (edible) or something like engine grease (decidedly, not).
Even if you can eat the grease, I'm not sure how much sustenance it will give you once the spell ends. It only lasts 1 minute and it's not like you can be casting it every minute to stay fed.
