Glossary

Terms we use in our testing protocol and reviews. Each entry is self-contained.

• 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.

• 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.

• 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.

• 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.