Project Zomboid B42 Weight Management: Losing (and Gaining) Weight in the Apocalypse
Build 42.19 · calorie pool, gain/loss thresholds, metabolism traits, and food calories. Not a real-world TDEE calculator.
How weight works in-game
Project Zomboid does not use a fixed “2,200 kcal/day + activity + 7,700 kcal = 1 kg” model. Your character keeps a calorie pool (about −2,200 to 3,700). Activity, body weight, and temperature drain it every second. Body weight only moves when that pool sits above a gain threshold or below a loss threshold. Fast / Slow Metabolism change those thresholds—not “±20% burn.” Use the planner below so meals and activity map to the weight arrow on your character panel.
Need carry weight or exercise XP?
Use the Strength & Weight guide for carry capacity and exercise. For the old free Underweight +6 myth, see Is Underweight a free trait?
Weight planner
Fast Metabolism
Cost −2 · harder to gain
Slow Metabolism
Cost −2 · easier to gain
Hearty Appetite
Cost −4 · hunger only
Light Eater
Cost +2 · hunger only
Nutritionist
Cost +2 · shows macros
Character & metabolism
Hearty / Light Eater change how fast Hunger rises. Nutritionist reveals food macros in the UI. Neither is a ±20% calorie burn multiplier.
Pool range is about −2,200 … 3,700. Weight only moves when the pool is outside the thresholds below—not from a daily “deficit vs 2,200.”
Weight status & thresholds
Normal Weight
Weight bandNormal
Gain threshold—
Loss threshold—
Base used for gain—
Macro multiplier1×
Direction at pool—
Set weight and calorie pool to estimate gain/loss.
Game-day activity burn (optional)
Estimated from Build 42.19 activity rates scaled by weight / 80. Hours should total about 24 for a full game day. Sandbox Day Length changes real-time length of a day, not these per-second drain rates.
Temperature / fever style multiplier on idle & sleep burn (1.0 = normal).
Hours accounted24.0
Est. pool drain / game day—
Food log (in-game calories)
| Food | Qty | Cal | Carb | Lipids | Remove |
|---|
If carbs or lipids on your character’s nutrition counters exceed 400, gain speed doubles; above 700 it triples. Log totals approximate a heavy one-day feed—live counters change as food digests.
Add food and set your pool/activity to get recommendations.
Build 42.19 food calories
| Item | Cal | Carb | Lipids | Protein | Notes |
|---|
Base values for unprepared items. Cooking, portioning, age, and animal meat variants can change live numbers. Open sealed cans before counting them as edible calories.
How weight actually moves
- Eating fills the calorie pool (and carb / lipid / protein counters). Activity and body weight drain the pool every game second.
- Pool is clamped roughly −2,200 … 3,700.
- Gain only while pool > gain threshold. Base threshold is 1,000, then gain = base + (weight − 80) × 40.
- Loss only while pool < loss threshold. Loss threshold = min(0, (weight − 70) × 30).
- Gain rate base is about 1.3×10−5 kg/s × macro multiplier × (pool / 4,000 capped at 1). Loss rate base is about 8.5×10−6 kg/s × (|pool| / 2,500 capped at 1).
- Macro multiplier: carbs or lipids > 400 → ×2; > 700 → ×3 (gain path only).
Metabolism traits (not ±20% burn)
- Fast Metabolism (cost −2): permanent lose bias. When weight > 70, gain base threshold becomes 1,800 instead of 1,000. Starts you at Low Weight (weight 70).
- Slow Metabolism (cost −2): permanent gain bias. When weight < 90, gain base threshold becomes 700. Starts you at High Weight.
- Both cost −2 points. Slow Metabolism is not “+2 free points.”
- Hearty Appetite cost −4; Light Eater cost +2. Hunger pacing only.
- Nutritionist cost +2 (free with the Nutritionist profession): shows food macros in the UI; does not change thresholds.
Live weight bands
| UI / state | Weight (kg) | Notes |
|---|---|---|
| Emaciated | ≤ 50 | Severe low-weight state |
| Very Low Weight | (50, 65] | Dynamic; not “everything under 65 is one band” |
| Low Weight | (65, 75] | Dynamic / granted by Fast Metabolism |
| Normal | (75, 85) | No weight-band trait |
| High Weight | [85, 100) | Continues until 100—not cut off at 95 |
| Very High Weight (Obese) | ≥ 100 | Obese state; sprint penalties stack further at very high mass |
Practical gain / loss habits
- Gain: stack fats and dense packages (Lard 4095, Butter 3200, Peanut Butter 2660, Cereal 2360). Keep the pool above the gain line for long stretches; high lipids help the ×2 / ×3 gain multiplier.
- Loss: stay hungry enough that the pool sits under the loss threshold; walking/running drain faster than idle/sleep. Low-cal produce alone is slow if you keep snacking the pool back up.
- Hunger ≠ calories: you can feel full while the pool is still low, or keep stuffing high-fat food while Hunger is fine.
- Rice cannot be eaten raw—cook it. Open canned meats before counting them as edible calories.
- Watch the weight arrow on the character panel; day estimates here assume a steady pool level and activity mix.
Common myths (do not use)
- “Base need = 2,200 kcal/day + fixed activity tiers” — not how the pool works.
- “7,700 kcal = 1 kg” — real-world rule of thumb; not the game rates.
- “Fast/Slow Metabolism = ±20% burn” — they change gain thresholds.
- “High Weight ends at 95 / Very High starts at 95” — High Weight runs to 100; Obese is ≥100.
- Mixing up which metabolism / appetite traits cost points vs give points.
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