How much food is considered substantial?

Question

Our group put it to a vote and 2 of 3 voted yes we want to keep track of food. I must implement it and I want to do it in the best way possible.

I've always been familiar with 3 weeks without food and your body is prone to fail. In this consideration, when presenting food items to my players, how much food do they need to keep fighting fit?

In the D&D 4E DMG:

When deprived of food, water, or air, the rule of three applies. An adventurer can handle three weeks with out food, three days without water, and three minutes without air outside of strenuous situations. After that, such deprivation is a significant test of a PCs’ stamina.

After which they provide the relevant checks.

I've dove a bit further back, which I do sometimes because not everything is in every edition, to D&D 3.5E DMG and found:

Characters might find themselves without food or water and with no means to obtain them. In normal climates, Medium characters need at least a gallon of fluids and about a pound of decent food per day to avoid starvation. (Small characters need half as much.) In very hot climates, characters need two or three times as much water to avoid dehydration.

I may just hybrid this aspect in but before I do, I want to know how much food is considered substantial in 4E?

Answer 1

It's not well defined.

• The Nature and Dungeoneering skills let you forage for food. They give you 'enough food and water for 24 hours' at a mere DC 15.
• The Food, Drink and Lodging table on PHB1 p222 tell you what a meal or a feast costs, or ale or wine. They don't tell you what's substantial, though.
• The Traveler's Feast ritual from PHB1 also just grants you 'enough food and water for 24 hours'. (It will feed several medium or two large creatures for 35gp and no check.)
• You can survive on 1 pound/day of trail rations, or 0.1 pounds/day of journeybread, which cost differing amounts per day. This means both price and weight are right out as a standard measurement of how much food is 'enough', since it varies depending on what the food is exactly.

This lack of attention combined with food becoming trivial to obtain around level 4 should suggest how much 4e actually cares about this: it doesn't, not very much. Enough is defined more or less as 'enough', so unless you're actually throwing your players into a starvation scenario, just assume that whatever they're eating is enough and move on to more exciting stuff, like the D&D 4e authors do.

If basic survival needs is important enough to your campaign that you want to zoom in on it, Dark Sun offers a survival subsystem which cares about you getting enough to eat. Bear in mind: Dark Sun as a setting focuses on a desolate and dying world, contrast to the default D&D 4e setting, Points of Light, which is flourishing with life and wealth. The survival systems are going to reflect this difference. (Indeed, PoL reflects it by considering food to not be a big deal at all!)

If you're used to previous editions like D&D 3.5e defining everything in minutiae, you won't find that in 4e. It leaves a lot undefined because it doesn't need to define that stuff, and doesn't care about that degree of simulation, and would rather just get onto the exciting rules about combat. Instead, it leaves you the DM the room to also not care, or just come up with whatever fluff you need, which is quite freeing. (3.5e having a table for everything is to me a burden, not a benefit, because most of those things are not worth the effort of understanding those rules.)

Answer 2

At least a pound of food per day, unless you splurge on journeybread.

Player's Handbook, page 222

• Rations, trail (10 days); 5 gp; 10 lb.
  
• Journeybread (10 days); 50 gp; 1 lb.