# Cryptonomicon's food-gathering program

In Neal Stephenson's book Cryptonomicon, a character in the story developed a system to calculate the different energy costs of a game character's activity, and the needed food intake to keep up with those costs. The purpose was to make the game more realistic by forcing the players to forage for food when needed. Unfortunately the book never went into the details of how such a system would work.

Is there such a system for real, software or just plain paper?

I'm sorry for lack of tags, I'm not sure how to tag this.

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There are two things that you need to implement such a system: a list of activities and their caloric costs per unit time, tailored to the age and weight of the character; and a list of the caloric values of various foods. A ready-made system for roleplaying games doesn't appear to exist, but given the mass of information out there for dieting and body-building purposes, such tables merely need to be compiled. Building such is beyond the purpose of a Q&A site, so I'm just providing the basic pieces below.

There is this daily calorie intake calculator to start with. It doesn't break down exercise beyond how many days out of seven and how much exertion (default vs "intense"). However, punching in weight, height, age, and 7-days-a-week of intense exercise would give you how many calories per day are required to maintain the current physical state. For example, punching in my numbers indicates that, were I an adventurer slogging through swamps and swinging four pounds of steel to save my life, I would need to consume up to 3597 calories per day of full-on adventuring, and about 1200 calories less on days of rest and relaxation.

To get more detailed, you could look at the calculation methods, as used by dietitians, that underlie these online calculators. The above online calculator offers three equations by name:

There are also caloric cost calculators online for specific activities. This Calories Expended site gives a drop-down of many activities, to which you can add the time spent and the body weight moved to find the calories used. You can probably find analogues for the various activities and adventurer might undertake in that list. You could use that calculator to find the cost of all activities in a day, and use the calories-required equations above as a "sanity test" to keep the numbers approximately correct.

The final piece of the puzzle is a list of foods and the calories they can provide. The Calorie Counter has extensive lists of foods and their typical caloric value. Although finding exact matches for foods in historical/fantasy settings is unlikely and would probably take some guessing to find approximate matches, for a more modern-day game the list should be spot-on.

Given those pieces, it should be possible to weld together a working system akin to the one in Cryptonomicon.

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If you can get your hands on a copy of 1st edition AD&D Wilderness Survival Guide, there are some things in that book that deal with food and water needs for adventurers. I seem to recall addressing some of these concerns in Twilight 2000, but I was only ever a casual player of Twilight 2000, so I don't know the rules that well or where to find them.

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Context can be important too. Food supplied in archaic settings is usually of far lower calorie density than at the modern supermarket: leaner, tougher meats, parasites, blighted wheat and the like. Old fashioned cooking/prep methods also extract lower share of the calories contained: medieval grist mills extracted maybe 50%, compared to modern 90% whole wheat, e.g.

There is some information on food needs for domestic animals, the main fact is that food supply oscillates over time from feast to famine. Same kind of problem for human hunter-gatherers, unless their round is undisturbed.

Both of these problems, and others like disease and horrid weather can be generalized by assuming fractions of the otherwise available food is at hand.

Fantastic situations allow wider range, new limits or fewer limits, as you wish.

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Original D&D suggested using the equally ancient Avalon Hill game Outdoor Survival for wilderness treks. I've played Outdoor Survival, and it is just that - you trying to keep your guy alive as he dehydrates and starves in the wilderness. It is equal parts awesome and terrible, but it addresses the question.

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Various methods from videogame programming come to mind...

The simplest, albeit a real pain to track without software or tokens, would be an energy level, which can't exceed some stat, and recovers only with food and/or rest.

Every extended action would require some number of these tokens; a combat might draw 1 if you never melee nor run, and 2 or even three if you did, or they ran over X rounds.

Any system with a fatigue stat can be modified easily to require food to recover long-term expenditures.

GURPS (and TFT) have a fatigue system, but it's short term (recovering with rest at 10min per point or some such; it's been too long). I don't recall a long-term for GURPS, but I remember someone had one on a website for TFT, which could readily be snagged for GURPS.

Many games have some limit on activity before sleep; I've seen none on tabletop tracking food on a during-the-day basis. But I've only read about 400 rulesets. (and run about 150.)

It can be modeled in Hero System by making Rec require a consumable replaceable focus (Food) and using the long term end rules. Since normals have a rec of 2-3... call it 500 calories per rec per day? This would make supers often eat 5-10 thousand calories a day...

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One of the things I'd like to incorporate to such a system would be to have the players look for food based on how their characters would like it, like we do in real life, instead of choosing foods based solely on their token-refilling capabilities. Any ideas how to encourage that kind of behaviour in a game? –  David McDavidson Sep 4 '10 at 13:55
If this is going to turn into system development, I don't think Stack Exchange is the place to do it. –  SevenSidedDie Sep 4 '10 at 17:17
I don't know that we'd mind questions asking for input on a given mechanic, but we can't design a system for someone. –  Bryant Sep 4 '10 at 18:09
Just give tokens 1-4 random markers of some larger number, and PC's get double value for 1 or 2, and 1/2 value for 1 or 2, and injuries for 1 or 2 (allergies). –  aramis Sep 4 '10 at 21:40
@ Bryant: this is still in the design theory stage. Credit, however, should be given if these ideas are used... –  aramis Sep 4 '10 at 21:41