Glossary
Nutrition terms, defined.
The 44 terms that come up most when you track calories and macros, each in a few sentences, with links to the articles that go deeper.
0–9
- 12:12 fasting
12:12 fasting is a daily eating pattern with a 12-hour fast and a 12-hour eating window, for example eating between 8am and 8pm. For many people it simply means not snacking after dinner, which is why it is often the first schedule people try before a longer fast such as 16:8. Like any fasting schedule, it sets when you eat, not what or how much.
- 16:8 fasting
16:8 fasting is an intermittent fasting protocol in which you fast for 16 hours and eat all of your meals within an 8-hour window, for example between noon and 8pm. It is the usual starting point because, for many people, it simply means skipping breakfast. It does not set what or how much you eat, so the calories eaten inside the window still decide the result.
- 18:6 fasting
18:6 fasting is an intermittent fasting schedule with an 18-hour fast and a 6-hour eating window, for example eating between noon and 6pm. It is a step up from 16:8 and is usually tried by people who are already comfortable with a shorter fast. The narrower window makes it harder to fit a day’s protein into fewer meals, so those meals tend to be larger.
- 20:4 fasting (Warrior diet)
20:4 fasting is an intermittent fasting schedule with a 20-hour fast and a 4-hour eating window each day, sometimes called the Warrior diet. It is one of the more demanding daily schedules, generally tried by people who already fast comfortably for 16 or 18 hours. With only four hours to eat, fitting in the day’s protein and nutrients takes more planning than on a wider window.
A
- Activity factor (Activity multiplier)
An activity factor is the number your basal metabolic rate (BMR) is multiplied by to estimate total daily energy expenditure (TDEE). Commonly used values run from about 1.2 for mostly sitting, through 1.375 for lightly active and 1.55 for moderately active, to about 1.725–1.9 for very active people and athletes. Choosing a level that overstates your activity is a common reason a calculated target comes out too high.
- Added sugar
Added sugar is sugar put into food or drink during processing or preparation, as opposed to the sugar naturally present in whole fruit or plain dairy. It brings calories with little fiber or nutrition, is common in drinks, sauces and flavored yogurts, and hides on ingredient lists under names like dextrose, corn syrup or cane juice. General guidance suggests keeping it under about 10% of daily calories.
- AI food recognition (AI photo logging)
AI food recognition is the use of a computer vision model to identify the foods in a photo, estimate their portion sizes and calculate the nutrition from that estimate. It replaces searching a food database by hand, which makes logging faster, especially for home-cooked and restaurant meals that have no label. The result is an estimate rather than a measurement, so every value should stay editable.
AI food scannerHow AI food recognition worksPhotos vs calorie databases
B
- Barcode scanning
Barcode scanning is logging a packaged food by scanning the barcode on its packaging, which looks the product up in a database and returns the manufacturer’s nutrition data. It is the most precise option for anything with a label, such as bars, yogurt, cereal and drinks. You still confirm how much you ate, because the database knows the product, not the size of your portion.
- Basal metabolic rate (BMR)
Basal metabolic rate (BMR) is the number of calories your body burns at complete rest, just to keep your organs and basic functions running. For most people it makes up roughly 60–70% of total daily energy expenditure. It is usually estimated from weight, height, age and sex with a formula such as Mifflin-St Jeor, then multiplied by an activity factor to estimate TDEE.
C
- Calorie (kcal)
A calorie is a unit of energy; on food labels and in nutrition it means the kilocalorie (kcal). Your body uses this energy for everything from breathing and organ function to exercise. Consistently eating more calories than you burn leads to weight gain, and eating fewer leads to weight loss. Protein and carbohydrates supply about 4 calories per gram, and fat about 9.
- Calorie deficit
A calorie deficit is eating fewer calories than your body burns, so it draws on stored energy; it is the condition for losing weight. A moderate deficit of about 300–500 calories a day below maintenance is the range most often described as sustainable, while very large deficits increase hunger and muscle loss. Underestimated intake is the most common reason a deficit on paper does not show on the scale.
Calorie tracking for weight lossNot losing weight in a deficit?
- Calorie surplus
A calorie surplus is eating more calories than your body burns, so the extra energy is stored and body weight rises. A deliberate, modest surplus of around 10–20% above maintenance is used alongside resistance training to build muscle. Muscle can only be added at a limited rate, and energy beyond that is stored as fat, which is why a bigger surplus does not build muscle faster.
- Carbohydrates (Carbs)
Carbohydrates are one of the three macronutrients, supplying about 4 calories per gram and serving as the body’s preferred fuel, especially for the brain and high-intensity exercise. They include sugars, starches and fiber. On a nutrition label, total carbohydrate is broken down into fiber and sugars, and those lines say more about a food than the total does.
D
- Daily Value (%DV)
The % Daily Value (%DV) on a nutrition label shows how much of a nutrient one serving provides, as a percentage of a reference daily intake. It is a quick way to judge whether a food is high or low in something: as a rule of thumb, 5% or less is low and 20% or more is high. It refers to one serving, so check the serving size first.
- Dietary fat
Dietary fat is the macronutrient with the most energy per gram, about 9 calories, more than twice as much as protein or carbohydrates. It supports hormone production, brain function and vitamin absorption, so it should not be cut too low. Most people do well with roughly 20–35% of their calories from fat, favoring unsaturated sources over large amounts of saturated fat.
E
- Energy density (Calorie density)
Energy density is the number of calories in a given weight of food, usually expressed per gram or per 100g. Foods low in energy density, such as vegetables, fruit, potatoes and lean protein, fill you up for few calories, while oils, nuts and cheese pack many calories into a small amount. Meals built around low-energy-density foods make a calorie deficit easier to keep.
F
- Fiber (Dietary fiber)
Fiber is the part of plant carbohydrate your body cannot fully digest, so it passes through the gut largely intact instead of being used for energy. Soluble fiber forms a gel that slows digestion, and insoluble fiber adds bulk. It keeps you full, steadies blood sugar and supports digestion. General guidance is roughly 25g a day for women and 38g for men.
- Food allergen
A food allergen is an ingredient that can trigger an allergic reaction in people who are allergic to it. EU labelling law names 14 major allergens, including cereals containing gluten, peanuts, tree nuts, milk, eggs, fish, crustaceans, molluscs, soy, sesame, celery, mustard, lupin and sulphites, and requires them to be emphasised in ingredient lists; US law names nine. They also turn up in sauces, dressings and processed foods.
- Food logging (Food diary)
Food logging is recording what you eat and drink, with the calories and nutrients of each item, in a diary or an app. Its main value is awareness: people commonly underestimate their intake by 20–40%, and even imperfect logging corrects much of that. Consistency matters more than precision, which is why faster methods such as photo or barcode logging help people keep the habit.
Building a tracking habit that sticksCalorie tracking without the obsession
G
- Gluten-free diet
A gluten-free diet leaves out gluten, a protein found in wheat, barley and rye and in many foods made from them, such as bread, pasta, beer and seitan. People with coeliac disease follow it for medical reasons, and others by preference. On EU labels gluten-containing cereals are emphasised as an allergen, and oats count as gluten-free only when certified, since they are often processed alongside wheat.
H
- Hand portions
Hand portions are a way to estimate serving sizes without a scale, using your own hand as the measure. A palm is roughly one protein portion (20–30g of protein), a cupped hand one carbohydrate portion (20–30g of carbs), a fist one portion of vegetables and a thumb one portion of fat (about 10–12g). Hands scale with body size and go everywhere you eat.
Tracking without weighing foodTracking calories at restaurants
I
- Intermittent fasting (IF)
Intermittent fasting (IF) is an eating pattern that cycles between set periods of fasting and eating; it governs when you eat rather than what. Common protocols include 16:8, 5:2 and OMAD. Studies show it can lead to weight loss, mostly because it reduces total calorie intake, and when calories are matched it performs similarly to ordinary calorie restriction. It does not suit everyone.
K
- Ketosis (Keto)
Ketosis is a metabolic state in which the body, short of carbohydrate, runs mainly on fat and the ketones made from it. A ketogenic (keto) diet aims to stay there by keeping net carbs very low, typically under 20–50g a day, with most calories from fat and moderate protein. A single high-carb meal can interrupt it, so keto depends on accurate carb tracking.
L
- Low-carb diet
A low-carb diet limits carbohydrates, most often to below about 130g a day, and makes up the energy with protein and fat. The strictest version, the ketogenic diet, keeps net carbs low enough, often under 20–50g, to reach ketosis. Much of the quick weight change in the first week of cutting carbs is stored glycogen and the water bound to it, rather than fat.
M
- Macro split (Macro ratio)
A macro split is the share of your daily calories that comes from protein, carbohydrates and fat, often written as percentages such as 30/40/30. It can also be set in grams, which is how many trackers, Pacali included, store macro targets. There is no single best split: a ketogenic diet puts most calories in fat, while higher-protein splits are common when building muscle.
- Macronutrients (Macros)
Macronutrients, or macros, are the three nutrients the body needs in large amounts and gets its energy from: protein, carbohydrates and fat. Protein and carbohydrates supply about 4 calories per gram and fat about 9, so a food’s calories follow from its macros. Tracking macros as well as calories shows whether your intake supports a goal such as building muscle.
- Maintenance calories
Maintenance calories are the daily intake at which your body weight stays stable, the same number as your total daily energy expenditure (TDEE). Every goal is set relative to it: below maintenance to lose weight, above it to gain. Formulas give a starting estimate, but the reliable way to find yours is to eat a consistent amount for two weeks and watch your weekly average weight.
- Mifflin-St Jeor equation
The Mifflin-St Jeor equation is a widely used formula for estimating basal metabolic rate (BMR) from weight, height, age and sex. For men, BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5; for women the last term is −161 instead of +5. Multiplying the result by an activity factor from 1.2 to 1.725 estimates TDEE.
N
- NEAT (Non-exercise activity thermogenesis)
NEAT, or non-exercise activity thermogenesis, is the energy you burn through movement that is not deliberate exercise: walking, standing, fidgeting, housework and errands. It varies a lot between people and from day to day. It tends to fall without you noticing when you eat less, through fewer steps and less fidgeting, which is one reason a calorie deficit can turn out smaller than planned.
Not losing weight in a deficit?Why your weight fluctuates daily
- Net carbs
Net carbs are total carbohydrates minus fiber, the carbohydrate your body actually digests and absorbs. The figure is used mainly on keto and low-carb diets, where the daily limit applies to net rather than total carbs. Confusing the two is a common tracking mistake: a high-fiber food can show a large total carbohydrate number while contributing far fewer net carbs.
- NOVA classification
NOVA is a food classification system that groups foods by the extent and purpose of industrial processing rather than by their nutrients. Its four groups are unprocessed or minimally processed foods, processed culinary ingredients such as oil and sugar, processed foods such as canned vegetables or cheese, and ultra-processed foods. It was developed by researchers at the University of São Paulo and is widely used in nutrition research.
O
- OMAD (One meal a day)
OMAD, short for one meal a day, is an intermittent fasting protocol in which all of the day’s food is eaten in a single meal, leaving the rest of the day as the fasting period. It is an advanced approach and is not recommended for beginners, since fitting a full day’s protein and nutrients into one sitting is hard. 16:8 is the usual place to start.
P
- Plateau (Weight-loss plateau)
A weight-loss plateau is a stretch in which your weekly average weight stops falling despite an apparent calorie deficit. Daily readings swing with water and food, so judge it on averages: under two weeks of a flat average is normal noise, while three or more weeks with genuinely consistent intake is worth investigating. The usual causes are portion creep, unlogged weekends and less daily movement.
Not losing weight in a deficit?Why your weight fluctuates daily
- Portion size
Portion size is the amount of a food you actually eat in one sitting, as distinct from the serving size printed on a label. Misjudging it is the biggest source of error in calorie tracking; people commonly underestimate portions by 20–40%, especially of calorie-dense foods like oil, nuts and cheese. It can be weighed, estimated with hand portions, or estimated from a photo.
- Protein
Protein is the macronutrient made of amino acids that the body uses to build and repair muscle, enzymes and hormones, and it supplies about 4 calories per gram. It is the most filling macronutrient and helps preserve muscle in a calorie deficit. The RDA of 0.8g per kg of body weight is a floor to prevent deficiency; active people are commonly advised 1.6–2.2g per kg.
S
- Satiety
Satiety is the feeling of fullness and satisfaction after eating that holds hunger off until the next meal. Foods differ widely in how satiating they are per calorie: protein, fiber, high water content and low energy density all increase it. Building meals around high-satiety foods such as potatoes, eggs, Greek yogurt, oats and lentils makes eating less easier without feeling deprived.
- Serving size
Serving size is the reference amount printed at the top of a nutrition label, and every number below it, from calories to protein, applies to one serving rather than the whole package. It is the most misread part of a label: a bag listing 150 calories per serving that holds three servings contains 450. Compare it with how much you actually eat and multiply.
- Sodium
Sodium is a mineral the body needs for fluid balance and for nerve and muscle function, and most of it in the diet comes from salt: 1g of sodium is about 2.5g of salt. Packaged, restaurant and processed foods supply most of it. Labels list sodium or salt per serving, and the World Health Organization recommends that adults keep sodium below 2g a day.
T
- Thermic effect of food (TEF)
The thermic effect of food (TEF) is the energy your body spends digesting, absorbing and processing what you eat, and it counts toward your daily energy expenditure. It differs by macronutrient: protein has the highest thermic effect, with roughly 20–30% of its calories burned during digestion, compared with much less for carbohydrates and fat. That is one reason protein-rich diets help with weight management.
- Total daily energy expenditure (TDEE)
Total daily energy expenditure (TDEE) is the total number of calories your body burns in 24 hours: your basal metabolic rate plus the energy used by all movement, from exercise to everyday activity. It is the same as your maintenance calories. It is usually estimated by multiplying BMR by an activity factor, and calculators can be a few hundred calories off, so real weight data refines it.
U
- Ultra-processed food
Ultra-processed foods are industrial formulations made mostly from substances extracted or derived from foods, often with additives such as flavourings, colours, emulsifiers and sweeteners; they are group 4 of the NOVA classification. Soft drinks, packaged snacks, sweetened cereals and many ready meals fall into it. On a label, the usual sign is a long ingredients list with items rarely used in home cooking.
V
- Vegan diet
A vegan diet excludes all animal products: meat, fish, dairy, eggs and usually honey. Protein comes from legumes, soy foods such as tofu and tempeh, seitan, nuts and seeds. Vitamin B12 is not reliably available from plants, so supplementation is standard advice for vegans, and iron, omega-3 and calcium are the nutrients most often watched on a fully plant-based diet.
- Vegetarian diet
A vegetarian diet excludes meat and fish but usually includes dairy and eggs; lacto-ovo vegetarians eat both, while lacto- and ovo-vegetarians keep only one. Eggs, milk, yogurt and cheese are complete proteins, which makes a protein target easier to reach than on a vegan diet. A pescatarian diet is a close relative that keeps fish and seafood.
W
- Water weight
Water weight is the short-term change in body weight caused by shifts in the water your body holds, not by gaining or losing fat. Salty meals, carbohydrate intake, hormonal cycles and hard training all move it, and each gram of stored glycogen binds about 3 grams of water. Daily swings of 1–2kg are normal, which is why progress is judged on weekly averages.
Why your weight fluctuates dailyNot losing weight in a deficit?
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