Glossary
Terms we use in our testing protocol and reviews. Each entry is self-contained.
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Mean Absolute Percentage Error (MAPE)
MAPE is the standard metric for measuring how far an app's predicted calorie value diverges from a known reference value, expressed as a percentage.
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Total Daily Energy Expenditure (TDEE)
The total number of calories a person burns in a day, including basal metabolism, the thermic effect of food, and physical activity.
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USDA FoodData Central (FDC)
The U.S. Department of Agriculture's integrated food composition database, used by researchers and consumer apps as a primary nutrient data source.
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Weighed Reference Meals
Meals whose ingredient masses are measured on a calibrated kitchen scale, with calorie content computed from USDA FoodData Central composition values, used as ground truth for app accuracy testing.