The index

The The Nutrition Dex glossary

50 entries on the infrastructure behind a credible calorie figure — USDA FoodData Central releases, FDA label regulation, kitchen-scale precision, laboratory reference meals, and the error metrics (MAE, MAPE, RMSE) a serious publication uses instead of adjectives. Each entry cites the primary source.

Dietary Assessment (44)

• 0.1g Scale A kitchen or laboratory scale specified to display weight in 0.1-gram increments — the precision tier required for …
• 1g Scale A kitchen scale displaying weight in 1-gram increments — the workhorse precision tier for meal-scale weighing, typi…
• 20% Tolerance (FDA) The FDA tolerance band in 21 CFR 101.9(g) permitting the analytically measured content of naturally-occurring nutri…
• Accuracy vs Precision Two distinct properties of a measurement system — accuracy is closeness to the true value, precision is the repeata…
• App Accuracy Rankings Published benchmark rankings of consumer calorie-tracking apps against a shared reference meal set — the most epist…
• Classification Accuracy vs Portion Accuracy The distinction between whether a food was correctly identified and whether the amount consumed was correctly estim…
• Daily Value (DV) The FDA reference intake figures used to contextualise nutrient content on Nutrition Facts labels — derived partly …
• Database Quality Tiers The stratified hierarchy of food-composition data sources by methodological rigour — from analytical USDA Foundatio…
• Density-Based Conversion The calculation that turns a volume measurement into a mass measurement by multiplying volume by the food's density…
• Dietitian-Weighed Reference A reference-meal protocol in which a trained registered dietitian prepares and weighs test meals under documented c…
• Dual Column Labeling The FDA-required two-column nutrition panel format used on packages containing 200 to 300 per cent of a single Refe…
• FDA Serving Size The per-serving reference quantity required on a Nutrition Facts panel, determined by the FDA's Reference Amounts C…
• Food Identification Accuracy The fraction of food items in a test set that a classification or recognition system correctly identifies — a prere…
• Foundation Foods The USDA's current-generation analytical food-composition dataset, distinguished by documented sampling protocols, …
• Ingredient Visibility Error The estimation error introduced when ingredients are hidden from view (dressings, sauces, cooking fats, buried comp…
• Inter-App Variance The spread of calorie and nutrient estimates produced by different tracking apps for the same food or meal — a prac…
• Kitchen Scale Precision The specification that determines how finely a kitchen scale can discriminate weights — 0.1g, 1g, or 2g are the thr…
• Label Rounding Rules The FDA-specified rules for rounding nutrient quantities on Nutrition Facts labels — increments that differ by nutr…
• Laboratory-Weighed Reference Meals Meals prepared and weighed ingredient-by-ingredient under controlled conditions, then analysed or calorimetrically …
• Liquid Volume Conversion The conversion between liquid volume units (millilitres, fluid ounces, cups) and mass (grams), with the wrinkle tha…
• Low-Light Photo Error The degradation in photo-based food-identification and portion-estimation accuracy that occurs when images are capt…
• Manufacturer-Verified Entry A food database entry sourced from the manufacturer's own submission or product-specification document — the top ti…
• Mean Absolute Error (MAE) The average of the absolute differences between estimated and reference values across a set of observations — the p…
• Mean Absolute Percentage Error (MAPE) The average of the absolute percentage differences between estimates and reference values — the accuracy measure mo…
• Measuring Cup vs Weight The accuracy gap between volume-based measurement (cups, tablespoons) and weight-based measurement (grams) — a gap …
• Mixed Dish Error The elevated estimation error specific to composite meals — casseroles, stews, stir-fries, curries, salads — whose …
• Nutrition Facts Label The FDA-regulated nutrition disclosure panel required on most U.S. packaged foods, governed by 21 CFR 101.9 and las…
• Per-Meal Error Band The expected range of estimation error for a single meal logged by a given method — the practical accuracy figure t…
• Percent DV (%DV) The ratio of a nutrient amount in a serving to the FDA Daily Value, expressed as a percentage on a Nutrition Facts …
• Portion-Size Error The contribution to total estimation error that arises from inaccurate determination of the amount of food consumed…
• RACC (Reference Amounts Customarily Consumed) The FDA regulatory table in 21 CFR 101.12 that assigns a reference serving amount to each of approximately 140 food…
• Raw vs Cooked Weight The gap between a food's weight before and after cooking, driven primarily by moisture loss and fat rendering — a s…
• Reference Meal Set A curated and documented collection of test meals, with per-meal ground-truth nutrient values, used for validating …
• Root Mean Square Error (RMSE) The square root of the mean of squared differences between estimates and reference values — an accuracy measure in …
• Scaling Accuracy The degree to which nutrient estimates scale linearly with portion size — the assumption, often unexamined, that do…
• Small Portion Error The relatively elevated percentage error that affects small portions — where a fixed absolute error (in grams or ki…
• SR Legacy The frozen April 2018 final release of the USDA's Standard Reference database, preserved inside FoodData Central as…
• Survey (FNDDS) The USDA Agricultural Research Service's dietary-recall reference database, tied to What We Eat in America and NHAN…
• Systematic Error vs Random Error Systematic error is a consistent bias that shifts all measurements in a single direction; random error is the scatt…
• Test-Retest Reliability The degree to which a measurement method produces the same result on repeated application to the same underlying re…
• Top-1 vs Top-5 Accuracy The convention for reporting classification performance at the strictest threshold (top-1, the single best predicti…
• USDA Branded Foods Database The manufacturer-submitted portion of FoodData Central, containing roughly 1.5 million packaged-food entries with l…
• USDA FoodData Central The U.S. Department of Agriculture's integrated food-composition database, comprising five source datasets and serv…
• Validated Photo Database A curated corpus of food images paired with laboratory-measured nutrient reference values — the ground-truth resour…

Biochemistry (6)

• Atwater Factors The 4-9-4 kilocalorie-per-gram coefficients (protein, fat, carbohydrate) derived from Wilbur Atwater's late-19th-ce…
• Atwater Specific Factors A refined set of Atwater coefficients that vary by food category to account for digestibility differences — used by…
• Bomb Calorimetry The laboratory method for measuring a food's total energy content by igniting a dried sample inside an oxygen-press…
• Fat Rendering The melting and separation of solid fat from meat during cooking — a component of cooking mass loss whose fate (dis…
• Moisture Loss in Cooking The reduction in a food's mass during cooking due to evaporation of water — the primary driver of the raw-to-cooked…
• Stock Absorption The uptake of cooking liquid — water, stock, wine, fat — by porous ingredients during cooking, which increases thei…