The Calorie Tracking Glossary

Every term below is defined in plain language, with a pointer to the guide that covers it in depth where there is one. Terms are grouped by where you will meet them: the energy numbers a tracker calculates, the nutrients it reports, the logging tools it offers, and the plans people follow.

Energy

Calorie (kcal). The unit of food energy. What food labels call a “calorie” is technically a kilocalorie.

BMR (basal metabolic rate). The energy your body uses at complete rest to stay alive. Usually the largest part of daily energy use.

RMR (resting metabolic rate). Like BMR but measured under slightly less strict conditions; the terms are often used interchangeably.

TDEE (total daily energy expenditure). Everything you burn in a day: BMR plus digestion, movement and exercise. Eating at your TDEE maintains your weight.

NEAT (non-exercise activity thermogenesis). Energy used in daily movement that is not exercise: walking around, standing, chores, fidgeting. It varies a lot between people.

TEF (thermic effect of food). The energy used to digest food, roughly 10% of intake.

Adaptive TDEE. A TDEE estimate that an app updates from your logged intake and weight trend, rather than a fixed formula.

Energy balance. The difference between what you eat and what you burn. A deficit (eating less) leads to weight loss over time; a surplus leads to gain.

Kilojoule (kJ). The metric unit of energy used on labels in Australia, the UK and Europe alongside kcal. 1 kcal is about 4.184 kJ, so a 2,000 kcal day is about 8,400 kJ.

Metabolic adaptation. A fall in energy expenditure during a diet that is somewhat larger than the change in body size alone would predict, partly through reduced everyday movement. See our guide to weight loss plateaus.

MET (metabolic equivalent of task). A way to express the intensity of an activity as a multiple of resting energy use. Sitting quietly is about 1 MET; brisk walking about 3.5 to 4; running at a moderate pace about 8 to 10.

Mifflin-St Jeor equation. The equation most calculators use to estimate BMR from weight, height, age and sex. It was published in 1990 and is generally considered more accurate for modern populations than the older Harris-Benedict equation.

Harris-Benedict equation. An older BMR equation first published in 1919 and revised in 1984. Still built into some apps and calculators.

Activity multiplier. The factor, usually between 1.2 and 1.9, by which a calculator multiplies BMR to estimate TDEE. People tend to choose a level higher than their real activity.

Calorie deficit. Eating fewer calories than you burn. A deficit of about 500 calories a day is often quoted as producing roughly half a kilogram (one pound) of loss a week at first, though loss slows over time.

Calorie surplus. Eating more than you burn, used deliberately to gain weight or support muscle growth.

3,500-calorie rule. The old rule of thumb that a pound of fat equals 3,500 calories. It is a reasonable estimate of the energy in a pound of fat tissue, but a poor predictor of long-term weight loss, because expenditure falls as you lose weight.

Nutrients

Macronutrients (macros). Protein, carbohydrate and fat, the nutrients that supply calories. Protein and carbohydrate provide about 4 kcal per gram, fat about 9, alcohol about 7.

Micronutrients. Vitamins and minerals, needed in small amounts.

Fiber. Carbohydrate your body does not fully digest. It supports digestion and fullness.

Net carbs. Total carbohydrate minus fiber (and sometimes sugar alcohols). Used mostly on low-carb and keto diets.

% Daily Value (%DV). On US labels, how much of a day’s reference amount one serving provides. See our label guide.

Added sugars. Sugars and syrups added during processing or preparation, as opposed to sugars naturally present in milk or whole fruit. US labels list them separately since the 2016 redesign.

Saturated fat. A type of fat found mainly in animal products and some tropical oils. Dietary guidelines advise keeping it below about 10% of calories.

Sodium. The part of salt that labels report. Most guidelines advise adults to stay under about 2,300 mg a day.

Sugar alcohols. Sweeteners such as erythritol, xylitol and maltitol that provide fewer calories than sugar. They often appear in “low sugar” and “keto” products and can cause digestive upset in large amounts.

Protein per kilogram (g/kg). The usual way to express protein targets relative to body weight. See how much protein to eat while losing weight.

RDA (Recommended Dietary Allowance). The daily intake of a nutrient that meets the needs of nearly all healthy people. It is a minimum to avoid deficiency, not necessarily an optimal amount.

Calorie density (energy density). Calories per gram of food. Water and fiber lower it; fat raises it. See our calorie density guide.

Glycemic index (GI). A ranking of carbohydrate foods by how quickly they raise blood glucose compared with pure glucose. Useful in some contexts, but it changes with portion, ripeness, cooking and what else is on the plate.

Logging

Serving size. The amount a nutrition label or database entry refers to. Always check it against what you ate.

Verified database. A food database whose entries are checked by the app maker, rather than submitted by users.

Crowd-sourced database. A food database built from user submissions. Large, but often full of duplicates with different values.

Barcode scanning. Logging a packaged product by scanning its barcode, which pulls in the label’s data.

Photo logging. Logging a meal by photographing it; the app estimates foods and portions.

Weight trend. A smoothed average of your daily weigh-ins, which hides day-to-day water swings and shows the real direction.

Recipe builder. A tool in most trackers that adds up the ingredients of a homemade dish so you can log portions. See how to log a home-cooked recipe.

Quick add. Logging a number of calories (and sometimes macros) directly, without picking a food. Useful when you only know the total, as with some restaurant meals.

Serving vs portion. A serving is the reference amount on a label or in a database. A portion is what you actually ate. They are rarely the same.

Raw vs cooked weight. Cooking changes the weight of food, mostly through water, while the calories stay roughly the same. A food entry must match how you weighed it.

Voice logging. Logging by speaking a description of a meal, which the app turns into entries.

Streak. The number of consecutive days you have logged. Many apps use streaks to encourage the habit.

Health integrations. Connections to Apple Health on iPhone or Health Connect on Android, which let a tracker read steps and workouts and share nutrition data with other apps.

Smart scale. A bathroom scale that sends your weight to an app automatically. Some also estimate body fat using a small electrical current, with limited accuracy.

Plans

Maintenance. Eating at your TDEE so your weight stays stable.

Cut / bulk / recomp. Lifting terms for eating in a deficit, eating in a surplus, and trying to lose fat and gain muscle at the same time.

Intermittent fasting. Eating within a set time window, such as 16:8 (16 hours fasting, 8 hours eating).

Time-restricted eating. A form of intermittent fasting in which all food is eaten within a daily window, such as eight or ten hours.

5:2 diet. A fasting pattern of eating normally five days a week and about 500 to 600 calories on two non-consecutive days.

Refeed / diet break. A planned period at maintenance calories during a longer diet, used to make the diet easier to sustain.

Body recomposition. Losing fat and gaining muscle at the same time, most realistic for beginners to strength training and people returning after a break.

Reverse dieting. Gradually increasing calories after a diet rather than returning to old habits at once. Popular in fitness circles; the main benefit is helping people find their new maintenance level carefully.

Macro split. The share of calories from protein, carbohydrate and fat, such as 30/40/30. There is no single best split; protein and fiber targets usually matter more than the exact ratio.

Ketogenic (keto) diet. A very low-carbohydrate, high-fat diet, typically under about 20 to 50 grams of carbohydrate a day, intended to shift the body into ketosis.

Body measures

BMI (body mass index). Weight in kilograms divided by height in metres squared. A quick screening measure that does not distinguish fat from muscle.

Body fat percentage. The share of body weight that is fat. Home methods, such as smart scales and tape-measure formulas, give rough estimates.

Lean body mass. Everything that is not fat: muscle, bone, organs and water.

Waist circumference. Measured around the middle, usually at the navel or between the lowest rib and hip bone. A useful companion to weight because it reflects fat around the abdomen.

Waist-to-height ratio. Waist divided by height. A value under 0.5 is a common screening threshold.

Related guides: How many calories do I need? · Calorie tracking for beginners · Read a nutrition label