Is a nuclear stomach worth it?

For a normal adult, the steady hunger saving is 1.2 nutrition per day. Ten comparable adults save 12 per day before meal waste and other modifiers. That can reduce cooking and hauling, but it does not mean every colony needs ten implants. Start with the pawn whose food demand matters most.

Start the research chain before food collapses. Crafting needs advanced production, and installation is surgery. If you already have the implant, medicine, and a capable doctor, use it; otherwise, fix the food supply first.

What the implant changes

• Hunger: stomach factor 0.25, before additive health offsets and the other multipliers.
• Digestion: 125% stomach part efficiency. On an otherwise healthy gut, Digestion moves from 100% to 112.5%.
• Sleep: that Digestion bump adds 3.75 percentage points to the rest-rate multiplier. It does not speed eating or stack another hunger discount.
• Illness: food-poisoning chance from eating drops to zero; gut worms are blocked, and an existing case clears when the artificial stomach takes over.
• Drawbacks: EMP makes the wearer vomit, and a random disease effect can create torso carcinoma.

A stomach does not improve the cook’s food-safety skill. Giving one to the chef protects that chef when eating; it does not make meals safe for everybody else. The other three artificial stomachs compared below also prevent gut worms.

The ×25% label does not multiply everything

For the combinations below, take the stomach’s factor, add neural supercharge (+0.20) and smokeleaf high (+0.30), then multiply by metabolic efficiency and Gourmand. A plain nuclear stomach looks like a −75 percentage-point cut from the starting 100%. That “offset” shorthand works for these examples, but health factors and health offsets are still separate steps in the engine.

The game first multiplies health-condition hunger factors together, then adds health-condition hunger offsets and clamps the result at zero. Trait, life-stage, bed and gene effects also matter. The simplified formula here is for a healthy, fed adult, with the selected stomach as the only non-default health factor.

With −5 metabolism and neural supercharge, you land at 1.62 nutrition/day, a hair above an unmodified adult’s 1.6. Compared with that same supercharged −5 pawn without the implant, you still cut 4.32 down to 1.62. What fails is assuming the final number is always one quarter of the unimplanted pawn’s hunger.

For the gene system itself, see metabolic efficiency and hunger. A positive score reduces the gene multiplier by 10% per point down to ×0.50 at +5; a negative score raises it by 25% per point up to ×2.25 at −5.

Carcinoma: frequency, pain and treatment

The implant targets the torso. At 100% Cancer rate, the base mean wait is 120 in-game days (two RimWorld years). You can roll earlier or later; treat 120 as a mean, not a safe window.

A torso already carrying carcinoma cannot receive a second carcinoma from this implant while that condition remains. Once it is removed, the implant can cause another. That does not protect other body parts from unrelated cancer sources.

Initial severity is 0.30. A torso efficiency penalty does not directly cut a listed capacity, but carcinoma can cause pain, and late stages can kill. Location alone does not make it cosmetic.

How risky is excision?

Ordinary surgery success caps at 98%. Excision has a special 25% fatal result on failure, so at that cap the special fatal branch alone is 2% × 25% = 0.5% per operation. This is not a guaranteed total death risk: a lower success chance raises it, and other failed-surgery injuries can also be dangerous. Use your best doctor and proper surgical conditions.

On a valuable pawn, tend while you line up a better cure. That is not a guaranteed walkaway: growth and remission are random, and tend quality matters. The “111-day cure” number floating around is an approximation, not a schedule you can bank on. Continuous tending can mean about 15 visits per 60-day year; medicine spend tracks care policy and how long the case sticks around.

Prevention and cure are different

Ageless ≠ Non-senescent. Stopping biological aging does not block this implant’s carcinoma giver. Removing the nuclear stomach stops future cases from this source, but an existing tumor stays until you treat it. If the pawn is already on luciferium, that healing helps; starting a lifelong dependency only to prop up a stomach swap is a much bigger call.

Healer mech serum or Anomaly healing abilities can cover a case when you have them, but you do not need them to run the implant. Budget them as scarce tools, not a free auto-cure for every future tumor. A biosculpter pod is not a carcinoma plan.

Nuclear vs reprocessor, sterilizing and bionic

These four replacements all provide 125% stomach efficiency and gut-worm immunity. The differences that matter are hunger, food poisoning, EMP and the nuclear stomach’s cancer effect.

Bionic is the conventional swap with no EMP vomiting. Sterilizing when the wearer’s food-poisoning risk is the problem. Reprocessor for a milder hunger cut without nuclear carcinoma. Nuclear when the hunger win outweighs the medical and EMP tradeoffs on that pawn.

Healthy colonists do not need any of these. If food, digestion, and illness are already fine, put the components elsewhere. Fleshmass organs use a different route and bring their own drawbacks; they are not craftable drop-ins in this table.

How to get and install a nuclear stomach

1. Unlock Artificial metabolism. Apply the one techprint, clear Fabrication and Prosthetics, then finish the project at a hi-tech research bench with a multi-analyzer. The techprint opens the gate; it does not finish the research.
2. Craft it. Fabrication bench, Crafting 8. Cost: 15 plasteel + 4 advanced components. WorkToMake 26,000 ticks at 100% speed; real time follows the worker. No uranium, no refuel bill.
3. Prep surgery. Keep the implant in reach and allow 2 herbal medicine or better. Doctor at Medical 5+ under decent surgical conditions.
4. Add the bill. Health → Operations → Install nuclear stomach. Base work 2,500 ticks. A failed install can destroy the item.
5. Verify. Confirm the stomach on the Health tab, then watch food use with the pawn’s current genes and conditions. Keep your own EMP off them.

Buying skips the crafting research. Check imperial traders and technologically advanced settlements that stock bionic parts. Inventory is random, and faction trading access still applies; no particular visit guarantees this implant. You still need medicine and a doctor to install a purchased one.

Removal is another operation. Remove part has 2,000 ticks of base work, uses 1 medicine of herbal quality or better, and has no minimum Medical skill. Successful removal returns the nuclear stomach item. The pawn will then need a replacement stomach, and any existing torso carcinoma still needs treatment.

Common surprises