About Nutrinaut Tools
Methodology and Sources
Source hierarchy, formula registry, validation rules, product heuristics and version history for every Nutrinaut tool.
Method standard
Transparent, deterministic and versioned
Calculator outputs are deterministic local calculations, not AI diagnoses. The same valid inputs produce the same result. Metric values are the canonical calculation path; pounds convert using 1 lb = 0.45359237 kg, feet using 30.48 cm and inches using 2.54 cm.
References support the method or context; they do not validate an individual result. Every numerical input is checked for a finite value inside a defensive product bound. Invalid values are rejected rather than silently clamped.
Source hierarchy
How evidence is selected
- Official standards and regulators. FDA, EFSA, EU regulations, USDA, NIH and other responsible public bodies.
- Professional consensus and systematic review. Used when the scope matches our recreational adult audience.
- Primary research. Used to establish an equation or clarify uncertainty, not to overgeneralise a single study.
- Product heuristics. Clearly labelled interface rules used for display or planning.
Formula registry
Eight core methods and practical comparison labs
| Tool | Core logic | Canonical units | Display rounding | Version |
|---|---|---|---|---|
| Maintenance & Energy Needs | Mifflin–St Jeor REE; × separate FAO PAL range | kg, cm, years | Nearest kcal; range to nearest 10 | Energy 1.2 |
| Protein per Meal | Body weight × 1.2–1.6 or 1.4–2.0; ÷ meals | kg, g | Daily whole g; meals 0.1 g | Protein 1.1 |
| Meal contribution comparison | Separate calorie/protein sums; meal value ÷ complete column total × 100; tied maximum | kcal, g, % | Shares 0.1%; unknown columns withheld | Comparison 1.0 |
| Workout Fuel Timing | Duration/intensity decision tree; contextual g/kg ranges | kg, minutes, hours | 0.1 g where useful | Fuel timing 1.1 |
| Nutrition Label Decoder | Serving multiplier or portion ÷ 100; amount ÷ DV/RI | servings, kcal, kJ, g, mg | Amounts 0.1; % whole | Labels 1.2 |
| Added Sugar & Drinks | Σ per-serving value × servings; sugar × 4 kcal/g | g, kcal | 0.1 g; whole kcal | Drinks 1.1 |
| Caffeine Dose & Timing | Σ mg; daily total ÷ kg; circular time-to-bed; disclosed caution rules | mg, kg, time | Whole mg; 0.01 mg/kg | Caffeine 1.1 |
| 7-Day Sleep Shortfall | Recorded-night shortfall and average; unknown nights excluded; complete-log three-night trend | hours | 0.01 hour | Sleep 1.1 |
| Recipe Yield / Grocery | Ingredient sum × portion ÷ measured finished mass; ceil(missing grams ÷ edible pack grams) × entered price | g, kcal, currency | Nutrients/amounts 0.1; cost 0.01; unknown totals withheld | Recipe Ledger 1.0 |
| Grocery & Meal Prep | Per-serving × servings × buffer − pantry; round to pack | user-selected units | 0.01 unit | Grocery 1.1 |
Label jurisdictions
US and EU/UK remain separate
US mode uses per-serving arithmetic and current adult/age-4+ Daily Values. EU/UK mode uses per-100 g or ml arithmetic and adult Reference Intakes. US protein is shown in grams without an automatic %DV, EU/UK kJ is entered separately from kcal, added sugar is never inferred from “of which sugars”, and salt is not compared directly with sodium.
Source register
The references behind each method
A new predictive equation for resting energy expenditure in healthy individuals
American Journal of Clinical Nutrition / PubMed · 1990 · Used by Maintenance & energy needs
Supports: Resting-energy equationHuman energy requirements: physical activity level
FAO/WHO/UNU · 2004 · Used by Maintenance & energy needs
Supports: PAL categories and uncertaintyNutrition and Athletic Performance
Academy of Nutrition and Dietetics, Dietitians of Canada and ACSM · 2016 · Used by Protein per meal
Supports: Active-adult protein ranges and meal contextInternational Society of Sports Nutrition position stand: protein and exercise
ISSN / PMC · 2017 · Used by Protein per meal
Supports: Protein ranges used for exercising adultsExercise and Athletic Performance: Health Professional Fact Sheet
NIH Office of Dietary Supplements · Current · Used by Protein per meal
Supports: Athlete protein range and scopeInternational Society of Sports Nutrition position stand: nutrient timing
ISSN / PMC · 2017 · Used by Workout fuel timing
Supports: Short-turnaround recovery contextHow to understand and use the Nutrition Facts Label
US Food and Drug Administration · Current · Used by Nutrition label decoder
Supports: US serving and %DV interpretationIndustry resources on changes to the Nutrition Facts Label
US Food and Drug Administration · Current · Used by Nutrition label decoder
Supports: Protein %DV quality-correction context and current US labelling requirementsRegulation (EU) No 1169/2011
European Union · 2011 · Used by Nutrition label decoder
Supports: EU declarations and Reference IntakesNutrition legislation information sheet
UK Government · Current · Used by Nutrition label decoder
Supports: Current UK nutrition-labelling sources and jurisdiction notesAdded Sugars on the Nutrition Facts Label
US Food and Drug Administration · Current · Used by Added sugar & drinks tally
Supports: Added-sugar definition and 50 g Daily ValueFoundation Foods documentation
US Department of Agriculture · Current · Used by Added sugar & drinks tally
Supports: General carbohydrate energy factor contextCaffeine topic and safety assessment
European Food Safety Authority · Current · Used by Caffeine dose & timing
Supports: Single-dose, daily and pregnancy reference valuesSpilling the Beans: How Much Caffeine is Too Much?
US Food and Drug Administration · Current · Used by Caffeine dose & timing
Supports: 400 mg context, variability and rapid-intake toxicity contextRecommended amount of sleep for a healthy adult
American Academy of Sleep Medicine and Sleep Research Society · 2015 · Used by Sleep shortfall planner
Supports: Adult sleep-duration consensusSleep and heart-healthy living
National Heart, Lung, and Blood Institute · Current · Used by Sleep shortfall planner
Supports: Adult 7–9-hour public guidanceMeal planning, shopping and budgeting
USDA SNAP-Ed · Current · Used by Grocery & meal prep
Supports: Planning and budgeting contextLeftovers and food safety
USDA Food Safety and Inspection Service · Current · Used by Grocery & meal prep
Supports: 3–4-day leftovers guidanceFood composition data: calculation of nutrient composition of recipes
FAO · 2003 · Used by Grocery & meal prep
Supports: Recipe yield, ingredient basis and limitations of nutrient calculations from food-composition dataHeuristic register
Rules we disclose rather than disguise
- Broad PAL ranges create a starting maintenance interval; they do not measure activity.
- Fourteen-day calibration and the ±0.25% trend band are planning heuristics.
- The 300 g/day protein warning is a display heuristic, not a safety threshold.
- A caffeine dose of at least 100 mg within six hours of bedtime triggers a conservative context flag, not a sleep prediction.
- A rolling 60-minute caffeine total of at least 1,200 mg triggers an urgent exposure message. The one-hour window is an implementation heuristic for rapid intake, not a regulatory cutoff.
- A ±0.25-hour sleep trend band labels a week as up, down or roughly steady.
- Grocery buffer and pack rounding are logistics choices, not nutrition recommendations.
Testing and correction
How calculations are checked
Each calculation has a hand-checked reference fixture. Across the suite, tests cover invalid, zero, negative, missing, extreme and unit-conversion cases. Tests reject NaN, Infinity, silent clamping and negative output where it cannot be meaningful. Editorial examples are recalculated when method code changes.
To report an error, include the URL, inputs, expected result, observed result and source if available. See the corrections workflow.
Version history
Recent corrections and releases
Added measured recipe yields, basis-matched ingredient estimates, weighed portions, edible-weight pack rounding and reader-entered costs. Unknown nutrition and prices remain incomplete; purchase cost is separate from allocated ingredient cost. Existing forms now clear stale results after input or row edits, kg/lb switching converts the entered weight, unsupported context choices are rejected, and fuel-timeline text follows the actual short-turnaround conditions.
Added reader-entered meal calorie and protein totals, separate percentage shares and tied rankings. Blank values remain unknown; incomplete columns have no percentage shares. The Protein 1.1 daily range is unchanged.
Synchronized this registry with the live tool pages. Versions now come directly from each tool definition to prevent a separate table falling behind again.
Energy and Label tools gained public arithmetic reference fixtures and clearer output reports. Sleep 1.1 distinguishes unknown nights from recorded zero, reports partial-log coverage and does not fill missing nights or extrapolate a full-week total.