Semi-realistic Regeneration and corresponding Increased Consumption
 

Greetings, all!

Due to closer scrutiny towards certain mutations and biomods, I'm interested in making the Regular Regeneration (1HP/hour) biomod at least semi-realistic in my campaign. That's an approximately 50-fold increase in natural healing capabilities compared to an average human (24HP per day instead of ½HP per day). Now, a person eats 3 GURPS meals per day, but most of that isn't spent on healing HP. So the question becomes: assuming that the process of regeneration has an impressively high coefficient of efficiency, just how much extra food would be required when the organism kicks into such a high gear? I'm assuming at least some of the damaged-but-retained biological material could be recycled by the nanites/weird-phagocite-and-mobile-stem-based-repair-cell-system, though I'm not sure at which point the semi-realistic turns into outright physics-defying. But even while building materials can be somewhat recycled, energy needs to come from somewhere - just how energy-intensive would be a 50-fold boost of healing, in terms of extra food consumption? Finally, how much of a buffer can be retained by using additional internal storage of nutrients/slow energy, purely through improvements to the biochemistry of storage (i.e. without resorting to making the person fat)?

Thanks in advance!

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I'm reminded of a kid who was born with the disease that he constantly generates skin cells. I imagine regeneration of this magnitude would be similar in idea. The person in question has to eat thousands (It was an absurd amount... something like 8,000 to 12,000?) of calories in protein a day or die.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I always like looking at this sort of thing. It's an interesting mental exercise.

Recycling material almost certainly involves some scary waste products - diseases like malaria and ebola rapidly dismantle cells, which produces a lot of chemical byproducts. Doing it quickly overwhelms the liver and kidneys (which both diseases make worse by directly attacking of course, but we'll assume the magic regeneration thingies have the sense not to do).

So you'd probably have a requisite of a boosted liver and kidneys if you want to go this route.

You also need to reclaim fluids that have been leaked into places they shouldn't go. That can be tricky, you'll be fighting the bodies natural inclination to swelling. There's also the cell-filled fluids and tissues that are flat out not in your body any more so there's limitations.

Faster than the digestive tract can help with if you're hoping to get it by eating after the injury, I suspect.

If you're not storing it as fat, then you must be storing it as sugars, which is pretty unheard of for mammals (tetrapods in general I think) but I don't see why you couldn't do it in genetic engineering or with nanites or with a sugar-water fuel tank or whatever. But you need more than just energy - you need all the nutrients, because that's what people are made of and you'll need to rebuild things.

If it's "only" a hole poked in you or a cut, then you need to build the scaffolding for new tissue, new tissue, and new blood volume (where's the water coming from?). We'll handwave how the nanites align your tissues correctly and keep them that way while healing without you being strapped in place.

If you've had major tissue damage (fire, chemical burns, the kinds of trauma that takes flesh right off you even if it's not a GURPS amputation that you need Regrowth for) then you need to magic that material out of somewhere. And the logical place for that is your other bones and muscles.

The most obvious way to store the reserves is extra-heavy bones and excess "unsupported" muscle mass that is dismantled by the nanites and relocated to where it's needed.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

A lot depends on the amount of reclamation of damaged tissue vs growth of new tissue. If you're simply growing new tissue, best-case for things like chicken farming is 2-3 pounds of food per pound of tissue, and bear in mind that the slaughtered chicken is something like 70% water while the feed is mostly dry. However, the amount of actually destroyed tissue in most injuries is fairly small, so if you can just do a good job of knitting damaged tissue back together you don't really need to create much new tissue (and different damage types would be different. Burning and corrosive damage should be relatively hard to regenerate, piercing and impaling relatively easy).

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Since After The End introduced Long-Term Fatigue (which I've been using for a lot more than just AtE games), I've been treating (semi-)realistic Regeneration as costing 1 LFP per HP, which very handily abstracts away levels of Increased Consumption, etc. into “your body is expending lots of resources on healing, so you're tired and need to rest, eat, and drink a lot to make up for it”.

Both I and my players love the reduction in bookkeeping, etc. that this brings on while maintaining verisimilitude.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I have read somewhere that 90% of a person's healing happens when they are asleep. (HGH and other useful hormone levels rise and temperature changes etc). Perhaps while healing/regenerating there are other changes in a person's physical and mental performance.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

But that's the thing about regeneration- any sort of fast regeneration is realistically NOT going to involve a lot of cellular generation, but instead focus on radically increased capability to 'glue' back together. Perhaps blood that contains some sort of very reactive chemical that upon exposure to nitrogen causes cells to loosen there bonds so that they will 'glue' to any other cells they encounter

A regenerator that simply had a more flexible and distributed cell structure (IE- more like an amalgam of independent cells that an interdependent network) could sustain many times over 'lethal' from a cutting weapon damage, and as long as the flesh has enough time to press against itself happily sew back together and cost essentially nothing except a series of lurid scars from the imperfect joining.

What would cost a lot of energy is constantly producing 'glue blood' (as anything that is reactive is by definition energy intensive), and the overhead for building (and maintaining) a multiply-redundant distribution structure (So that simply glueing flesh back together leaves it functional instead of numb and dying in the event of a nerve cut or vein/artery damage).


So a 'realistic' regenerator would have increased consumption, but no special fatigue cost for the act of regenerating (at least beyond the fatigue cost you would apply to a human to have suffered identical wounds).

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Well, it could easily have limited reserves of supercoagulin or whatever you choose to call your glue blood, which means the regeneration shuts off after a while and healing rate drops to normal (or some elevated or depressed normal, depending on the way the special blood is generated).

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Real-world medical recommendations seem to be 30-35 Calories (kcal) per kg of body weight, sometimes more. That number also assumes that you're idle in your hospital bed, so the usual maintenance requirement is reduced. So, it's something like a 10% increase over normal maintenance, or more.

If we take a 10% increase and assume it's linear with the 50-fold increase in healing, that's 5x food to fuel the Regeneration, or 6x with the normal food intake. Though the pentaphilic number is appealing :)

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I think that's a bit of a misdirection as he obviously was not using all that protein for fuel. So the caloric density means little as he used it for building materials.
No normal sized human could breathe fast enough 24/7 to oxidize 12k Calories worth of food a day. Just imagine breathing five times as fast as you do normally but constantly.
I remember the poor guy you're probably thinking of. Feeding tube during the night to ingest the sheer volumes of pure protein slurry needed. Even the dual facts of his constantly red cracked sloughing skin and that he swam in the salty ocean made me cringe.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I played around a bit with the ideas here and my own, and got this:

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Both of these posts are Solid. Freaking. Gold. I just had to pop in and say that. I normally don't. But these are awesome.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I now know the mechanics when my players have the Jaffa that have allied with them wounded. I hadn't realized that I needed that.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I'll second that.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

How does AtE's LFP compare to the role that The Last Gasp gives to normal FP (with AP taking the short-term FP role)?

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Long-Term Fatigue are essentially regular Fatigue Points with a “generic” Hazard attached. You lose LFP and regular FP from starvation, dehydration, missed sleep and such, and you regain them only when you are getting regular meals and enough sleep (and at twice the rate if you do nothing but eat, drink, and rest for that day).

I actually have a half-written version of my own Last Gasp-style tiered fatigue system based on AtE's LFP — I like what The Last Gasp did in terms of making fatigue realistic, but the bookkeeping is horrendous, and I'm trying to take the best lessons from both systems and strike a good balance between verisimilitude and playability.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Re: LFP and Regeneration. I think a custom limitation could be had here


So if Costs Fatigue (once per minute) is -5% you could modify that with the Hazard modifier. Since LFP is a combination of starvation, sleep, and dehydration, and environmental hazards. You could use the most costly modifier - Missed Sleep (+50%) as the base and then 1/5 of the cost of the others: Dehydration, +4%; Heat, +4%; Freezing, +4%; Starvation, +8%.

This would give a +70% modifier total to the Costs Fatigue modifier. Since this comes to -8.5% I'd just round that up to -10%. So it seems plausible that costing LFP vs. FP adds a another -5% to the final modifier. So if an ability costs you 1 LFP per hour of use that's -5%, per minute would be -10%, and once per second would be -15%. Honestly though. That doesn't seem worth it in most cases. I think I'd just do either a an additional -10% on top of the base cost or double the finl cost (minimum of -5%).

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I think nearly everyone agrees that costs fatigue -5% is absurdly undervalued for most situations. From all day every day to around 10 uses along with removing a useful reserve for other survival oriented abilities is FAR more hampering than noisy; makes stealth difficult, to use another -5% limitation as an example.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Not on target for the thread, please don't derail this one, Flyndaran. Start another one.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Indeed, I've been using PK's house rules for Costs Fatigue for years and years, and have been pricing “Costs LFP” the same as “Costs HP” — and “Costs 1 LFP per HP” for Regeneration as -15%.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

If someone's going to create a write up that involves costs fatigue, I don't see why talking about it is off topic. But whatever.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

In high school I worked out 3-5 hours per day and ate 6000 kcal per day. And that level left me athletic but nearly without body fat. I'm sure actual athletes ingest and burn even more each day. So i think your assumption was flawed.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Yeah, right now I need about 3kcal per day or I become extremely weak and disoriented. In high school I needed about the same amount. Also when I was unloading/loading trucks and doing asset protection/bodyguard work. I may be big, but I have a very high metabolism.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

If we're verging into FP-cost builds anyway, it seems like an on-target comment aimed at your post.

Hmm. Regeneration of hit points in exchange for a buildup of toxins in the blood seems like an interesting mechanism. That being said, a boosted liver is right behind the corner for our inventor, and kidneys are not far behind. Talk about incentives.

This doesn't sound as bad. At a minimum, extra drinking for replacing lost fluids (e.g. blood loss) is seemingly much easier than consuming as much food. But getting rid of extraneous fluids where they're harmful - I'm not sure how exactly that should be done; I'm inclined to believe this will be one of the major contributors for shifting one step closer to Unusual Biochemistry, but not all the way.

Ultimately recommending an IV drip is definitely in the alpha-version description of the biomod.

I don't recall the precise numbers, but IIRC ('normal') sugars don't provide an enormous storage efficiency advantage, so might need to think of something else. Quick wiki check gives sugars 17MJ/kg, while fats get 37.

Even ethanol has only 26. Though a hacked metabolism that can safely handle lots of alcohol and use its energy to fuel ATP production would be amusing.

Hmm. Needing to consider the difference between cutting/impaling and destroying damage types seems like a bit complicated for the game I'm running. But the fact that the former can be modest in requirements is a plus.

Looks good as an alpha-version of the biomod.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

You're the OP. I just didn't want it derailed with "This sucks! Change it!" which Costs Fatigue seems to always devolve into.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

*shrug*
You're the first one to bring up the FP cost build (in reply to the LFP ideas), not Patrick.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I was suggesting sugars because you specified "not fat", but mobilizing fat reserves has more potential for liver failure. Malnutrition causes mobilization of fat, which can choke the liver, leading to fatty liver, and then we're back to liver failure again. Plus pressure of your engorged liver on your other abdominal organs and the enormous amount of heat being produced by your liver struggling to process everything (which is wasted calories and also gives you a fever).

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

I was very specifically speaking about Costs FP as it stands in RAW (which is contentious). That's it.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Oh well, I was hoping for something that is better than fats, but I guess that's not much of an option. Not with anything resembling mammalian biochemistry, it seems. I'll have to break out the bio-alchemy then. And liver upgrades.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Since you're talking about nanites, other options would be things artificial sources, like a battery pack or more high-energy reactions that would be dangerous to do right in the circulatory system but could be done in little "reactor units" distributed around the body. By reactor I mean chemical reactor, not nuclear - I don't think you want RTGs in your body at any TL :D

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Well, I am, a bit, but that's something of a . . . necessary analogy, because the original TL10 Regular Regeneration biomod comes from nano. I'm actually trying to get something more plausible-sounding and less cliché. A borderline organic construct that is halfway between blood cells and nanites is approximately what I'm hoping for. Things are meant to be weird-sciencey, with mild TL^, but not something as drastic as ignoring conservation of energy. It's meant to be based on rare and weird divergent strain of humanoids of the setting (who tend to have both detrimental and beneficial mutations). Great Old Entities are involved by proxy, but the overall style of the setting/campaign is meant to be soft sci-fi//science-fantasy, not pure fantasy/horror. I'm not sure how many of these details are relevant/interesting/useful for this discussion.

Stuff that says that recipients really should get Resistant to Metabolic Hazards too if they want to use it is actually appropriate for this invention.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Most likely the biggest reason why most animals store most energy as fat is more due to how it's possible to store it in pure form. Sugars are so water hungry that you end up storing far fewer calories per gram than fat when you include the dead weight.
I imagine concentrated ethanol has its own problems.
Then again, making your very tissues toxic to most other organisms even if it costs you something in return isn't inherently a bad design.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Using loads of protein for calories blows out organs from all the excess nitrogenous waste.
There really are good reasons why carbs are the go to foods for most omnivores. We diabetics not included. ;)
But even I feel the pinch as it seems to take more effort to bring my reserves to bear than it did before the -betus. Possibly unrelated and anecdotal of course.
For hummingbird level metabolic activity that super regen. would require though, boat tons of sugar seem about the most plausible fuel.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Ethanol doesn't seem particularly energy-dense. The idea of recharging by consumption of large amounts of ethanol is amusing, though. And yeah, tissues being toxic (by our standards, that is) is quite par for the course for many lifeforms of the afflicted area. But many of those solutions would not be suitable for biomods installed into more human-like humanoids, since they would require replacing all cells with more robust ones. Now, dumping toxings into blood as byproducts and having them immediately handled by the boosted filtration systems - that's about perfect from the conceptual PoV.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

A pound of fat optimally has around 3600 Calories. How much energy is your character needing that that density of storage won't keep him going between meals?
I think men can go down to around 5% body fat safely, and no one's calling one with 15% unhealthy. That gives a full 10% to play with. For Gurps 150 lb, that's a full 15 times 3600 or 54000 Calories storage. Multiplied by 4.184 means over a quarter of a million kilojoules.
Assuming I did my basic math correctly.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Well, only our stomachs can handle such a low pH, so it might be possible to create a very insulated organ for ethanol storage. But risky as heck, I agree.

If you want something that's going to cause major total body effects, it seems difficult to implausible not to have to screw around with all tissues in some ways.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

How much energy (and materials) is needed is a hard question, which some people above attempted to answer. Anthony's approximate calculations seem to yield a requirement of extra 15 meals per nychthemeron of regeneration (about 24-25 HP).

Carrying 15 meals worth of energy and nutrients seems like it'll be no less than (¼ lbs × 15) = 3¾ lbs per day of supply. Which seems . . . very noticeably more than the typical day-to-day mass change (most of which is water anyway), but about plausible for a boosted organism.

There is however one interesting side effect of such an ability:
if the organism can store and 'pull out' this much stuff from storage on a short notice for regeneration, it stands to reason that it can also be used by the organism to mitigate FP loss from starvation equivalent to those same 15 meals. Which is actually a lot, essentially comparable to 5 days of Doesn't Eat that can be 'recharged'.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Ethanol is only 26MJ/kg, compared to fat's 37. So it's no good for storage, only for quick delivery. As I said, getting some extra energy by rapidly consuming ethanol, and having the the boosted inhuman-garbage-collector blood cells quickly clean up all the byproducts (and sending them on their way out) would be an amusing detail, but that's probably about it.

Also, there's a difference between stuff that permeates all tissues and stuff that only accumulates in large amounts in specialized cells. E.g. the concentration of oxygen in erythrocytes would probably be unhealthy for some other tissues, even while smaller concentrations of it are quite necessary for all or nearly all cells.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

Some fruitbats can more-or-less properly digest alcohol (I understand it's not so much that they don't produce the toxic byproducts, and more that they tolerate the toxic byproducts). They aren't inedible either, at least as far as I know.

I assume many fruit-colonizing insects can tolerate at least some of their diet being alcohol too, at least for the phase of their lifecycle where they live in the fruit. Otherwise they'd be pretty screwed.

Your regeneration doesn't necessarily need to be powered by booze, if the organism simply uses alcohol as one nutrition source of many to build back up and/or maintain its fat reserves for the next bout of regeneration.

Fat is more calorie dense than sugars or alcohols, but digesting lots of fat takes specialized anatomy. Polar bears take a huge portion of their diet in fat, and may be the world leader in terrifying bile production. Polar bears will even kill seals just to eat their fat, leaving everything else, because of the huge amount of fat intake they require. Polar bears, of course, are using all that fat to not freeze to death; females even bigger reserves when pregnant and nursing, because they den up and don't eat during that period.

So as a side effect, they have freaky bile sacks producing really potent bile. Bile, of course, is a detergent that breaks up the fat and makes it water soluble, making it biologically available. If you don't have enough bile for the fat you're eating, the leftover fat will just go out of your body (which is nasty). So there's another modified organ that you don't need but will probably want to support this.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

You can do better than fats by having something that's closer to the finished product and thus requires less energy to finish the job. If we've got some form of material that can rejoin damaged tissues more effectively than existing mammalian biochemistry (coagulin et al), your least weight option is probably to store deeper reserves of that material, and package it with just enough surplus energy to power its normal transformation.

Mechanically speaking this would be closer to limited uses than costs fatigue, though limited uses is highly inefficient on hourly regeneration.

Re: Semi-realistic Regeneration and corresponding Increased Consumption
 

There were a couple of fantasies where magic was powered by the magicians own reserves. So if you hired a mage to deal with something the pay was enough for him to get back up to "fighting" weight after he goes from 400 pounds to skinny in a couple seconds of casting.