What is a calorie deficit?

Account deletion

Account deletion is the removal of an account and the data it holds at the person's request, as distinct from cancelling a subscription, which stops the payment and keeps the record.

An activity factor is the multiplier a calculator applies to a resting metabolic rate to estimate a whole day's expenditure, from about 1.4 for a sedentary life to 2.4 for a vigorous one in the FAO/WHO/UNU scale.

Adaptive thermogenesis

Adaptive thermogenesis is the drop in energy expenditure, beyond what a smaller body would explain, that a prolonged deficit tends to produce, the body's way of spending less when less comes in.

Added sugar

Added sugar is sugar put into a food during processing or preparation, as opposed to the sugar naturally present in fruit, milk or vegetables, and some labels list it as a separate line.

Adherence

Adherence, in food logging, is how much of the time a person keeps recording, measured as days or weeks with a record against the days they meant to record.

AI assistant

An AI assistant, in food logging, is a conversational model such as ChatGPT or Claude that understands a sentence about a meal, asks what is missing, and writes the record for the person.

Authorization screen

An authorization screen, or OAuth consent screen, is the page where a person signs in to a service and approves an application's access to their account, so that the application receives a token rather than their password.

Barcode

A barcode, in food logging, is the product code on packaging that a database can match to the product's declared nutrition figures, so that scanning replaces reading the label.

Batch cooking

Batch cooking is preparing a large quantity of one dish at once, to be eaten in portions over several days, with the whole batch weighed and divided.

BMI

BMI, body mass index, is weight in kilograms divided by height in metres squared, a population screening figure that says nothing about how much of a body is fat or muscle.

BMR

BMR, basal metabolic rate, is the estimated energy a body uses at complete rest over a day, before any movement or digestion is counted.

Body composition

Body composition is the split of a body's weight into fat mass and lean mass, the figure that distinguishes two people of the same weight and the one a scale alone cannot give.

Body fat percentage

Body fat percentage is the share of a body's weight that is fat, measured by scans, calipers or impedance scales with very different accuracy, and estimated by many apps with almost none.

Bulking

Bulking is the phase of a training cycle spent in a calorie surplus to gain muscle, accepting some fat gain along the way, the counterpart of cutting.

Calorie

A calorie, on a food label and in everyday use, is the kilocalorie: the unit in which the energy a food gives the body is counted.

Calorie surplus

A calorie surplus is a period during which a person takes in more calories than their body uses, so that the extra is stored, as muscle when training drives it and as fat otherwise.

Calorie target

A calorie target is the daily number of calories a person chooses to aim for, above, below or at their maintenance.

Calories left

Calories left are the difference between a day's target and what has been recorded so far, the figure people compose their next meal against.

Carbohydrate

A carbohydrate is the macronutrient made of sugars and starches that the body turns into glucose for energy, at about 4 kcal per gram.

Change history

A change history is the list of every change made to a record, with what was before, what came after and when, kept so that the current state can always be explained.

ChatGPT

ChatGPT is OpenAI's conversational assistant, and in relation to IZeat it is one of the assistants a customer can connect so that a sentence about a meal becomes a record.

CIQUAL

CIQUAL is the French food composition table published by ANSES, the national food safety agency: reference figures per 100 g for the foods eaten in France, generic rather than branded.

Claude

Claude is Anthropic's conversational assistant, and in relation to IZeat it is one of the assistants a customer can connect, on the web, in the desktop app, on the iPhone app and in Claude Code.

Complete protein

A complete protein is a food whose protein contains all nine essential amino acids in useful amounts, as most animal foods and a few plant foods such as soy and quinoa do.

Confidently incorrect

Confidently incorrect is the phrase people use for an assistant's wrong answer delivered in the tone of a right one, with no hedge, no source and no sign that it was a guess.

Connector

A connector is an assistant's name for an outside service it has been linked to, so that the model can use that service's tools inside a conversation.

Cooked and raw weight

Cooked and raw weight are the two weights a food can be measured at, and for foods that absorb or lose water they differ enough to change the calories by a third or more.

Cooking fat

Cooking fat is the oil, butter or other fat a food is fried, roasted or dressed in, an ingredient that a plate does not show and that can add a third or more to a dish's calories.

Correction

A correction, in a food record, is a change to something already recorded, a wrong portion, a forgotten item, a meal on the wrong day, made after the fact.

Crowd-sourced database

A crowd-sourced food database is a tracker's catalogue of foods typed in by its own users, brands and generics mixed, where the same food can appear many times with different figures.

Cutting

Cutting is the phase of a training cycle spent in a calorie deficit to lose body fat while keeping as much muscle as possible, usually with protein kept high.

Data export

A data export is a copy of everything an account holds, delivered in files the person can open elsewhere, so that a record is theirs rather than held by the service that recorded it.

Day in your time zone

A day in your time zone is the calendar day where the person is, which decides which day a meal belongs to, not the day where a server happens to sit.

Day total

A day total is the sum of the calories and macros of everything recorded on one day, in the person's own time zone.

Diet break

A diet break is a planned period of one or two weeks at maintenance calories in the middle of a longer deficit, before the deficit resumes.

Eating out

Eating out is any meal prepared by someone else outside the home, a restaurant, a takeaway, a friend's table, where the ingredients and the portions are not the eater's to weigh.

Energy balance

Energy balance is the relation between the energy taken in as food and the energy a body uses: intake above expenditure stores energy, intake below draws on stores, and equal keeps weight steady.

Energy density

Energy density is the number of calories in a given weight of food, usually per 100 g: the quantity that separates a plate of vegetables from the same weight of pastry.

Estimate

An estimate is a figure reasoned out from what is known when the exact value cannot be measured, and it is honest only when it is called an estimate.

Fat

Fat is the macronutrient that carries the most energy per gram, about 9 kcal, and that a body uses for energy, for storing it, and for building cells and hormones.

Fibre

Fibre is the part of plant carbohydrate that the body does not digest into glucose, listed on labels as dietary fibre, and counted at a lower energy value than other carbohydrate where it is counted at all.

Food composition table

A food composition table is a published dataset giving the energy and nutrients of generic foods per 100 g, measured across samples by a national or international agency.

Food diary

A food diary is a dated record of everything a person ate and drank, with quantities, kept to know a day's intake rather than to remember it.

Food logging

Food logging is writing down what was eaten, with quantities, so that a day's calories and macros can be known rather than guessed.

Glycaemic index

The glycaemic index is a scale from 0 to 100 that ranks a carbohydrate food by how fast it raises blood glucose compared with pure glucose, measured in people rather than printed on labels.

Hallucination

A hallucination, in an AI assistant, is a confident statement with no basis, a figure, a fact or an action the model produced because an answer was expected rather than because it knew one.

Hunger scale

A hunger scale is a self-rating of hunger and fullness, usually from one to ten, used to notice eating that is driven by habit or mood rather than by need.

Intermittent fasting

Intermittent fasting is an eating pattern that alternates periods of eating and periods without food, by the clock or by the day, rather than a rule about what is eaten.

IZeat

IZeat is the calorie tracker inside ChatGPT, Claude or any other assistant. Tell the assistant you already use what you ate instead of searching for foods and entering them one by one.

Kilojoule

A kilojoule, kJ, is the metric unit of energy used on food labels in Australia, New Zealand, South Africa and alongside calories in the European Union; one kilocalorie is 4.184 kilojoules.

Label values

Label values are the calories and macros printed on a food's packaging, per serving or per 100 g, as declared by the producer.

Lean mass

Lean mass is everything in a body that is not fat, muscle, bone, organs and water, and it is the part a deficit is meant to keep while fat is lost.

Logging frequency

Logging frequency is how often a person records, counted in days with an entry or entries per day, as distinct from how long each recording session takes.

Macro split

A macro split is the share of a day's calories planned to come from protein, carbohydrate and fat, written as three percentages or as three gram targets.

Macronutrient

A macronutrient is one of the three nutrients a body needs in gram quantities and draws energy from: protein, carbohydrate and fat.

Macros

Macros, short for macronutrients, are the three nutrients that carry a food's energy: protein, carbohydrate and fat, measured in grams.

Maintenance calories

Maintenance calories are the daily intake at which a person's weight stays the same over time, because what comes in matches what the body uses.

MCP

MCP, the Model Context Protocol, is an open standard that lets an assistant such as Claude or ChatGPT call tools offered by an outside service, with the service describing each tool in words the model reads.

Meal prep

Meal prep is cooking and portioning several meals in advance, so that the same weighed meal is eaten on several days without being made or measured again.

Meal type

A meal type is the slot of the day a meal belongs to: breakfast, morning snack, lunch, afternoon snack, dinner or evening.

Menu calories

Menu calories are the energy figures large restaurant chains print next to dishes on their menus where regulation requires it, declared by the chain for a standard portion.

Metabolism

Metabolism is the whole set of chemical processes by which a body turns food into energy and tissue; in everyday use, the word means the rate at which a person burns energy.

Micronutrient

A micronutrient is a vitamin or a mineral, a nutrient the body needs in milligram or microgram amounts and that carries no energy.

Moving average

A moving average is the mean of the last few values in a series, recomputed as each new value arrives, so that a noisy daily figure becomes a readable line.

NEAT

NEAT, non-exercise activity thermogenesis, is the energy spent on everything that is neither sleeping, eating nor deliberate exercise: walking, standing, fidgeting, housework.

Net carbs

Net carbs are a food's carbohydrate minus its fibre, and sometimes minus sugar alcohols, a figure used by low-carbohydrate diets and printed on some packaging rather than on official labels.

Nutrition label

A nutrition label is the panel on packaged food that declares its energy and nutrients per 100 g or 100 ml and, in some regions, per serving, as required by regulation and declared by the producer.

Omega-3

Omega-3 fats are a family of polyunsaturated fats found mostly in oily fish, walnuts, flax and chia, that the body cannot make and has to eat.

Open Food Facts

Open Food Facts is a free, open database of packaged food products and their label figures, built by volunteers who photograph packaging, and published under the Open Database License.

Per 100 g

Per 100 g is the reference amount most labels and every composition table use to state a food's calories and nutrients, so that any portion can be computed by scaling.

Per serving

Per serving is the second way labels state figures, for an amount the producer chose as a serving, which is often smaller than what a person eats and differs from one product to the next.

Period average

A period average is the mean of daily totals over a range of days, counted over the days that have entries rather than over the calendar.

Plate photo estimate

A plate photo estimate is a calorie figure produced from a picture of a served dish, which can tell what the food is but not how much is on the plate nor what it was cooked in.

Plateau

A plateau is a stretch of weeks during which weight stops changing although the person has not changed what they do.

Portion control

Portion control is deciding the amount of a food before eating it, by weighing, measuring or dividing, rather than eating until the plate is empty.

Prompt

A prompt, in food logging, is the sentence a person writes to their assistant about a meal, a question or a correction, in their own words and their own language.

Protein

Protein is the macronutrient made of amino acids that the body uses to build and repair tissue, muscle included, and that carries about 4 kcal per gram.

Protein target

A protein target is the number of grams of protein a person aims to eat in a day, set alongside or instead of a calorie target.

Rate of loss

A rate of loss is the pace at which weight changes over weeks, usually stated in kilograms or pounds a week, and the pace public health services describe as sustainable is about half a kilogram to one kilogram a week.

Receipt

A receipt is the reply that states what was recorded, item by item, so that the person narrates from what happened and not from what they believe they said.

Recomposition

Body recomposition is losing fat and gaining muscle over the same period, usually at or near maintenance calories with high protein and resistance training.

Recorded day

A recorded day is a calendar day that has at least one meal in the record, as opposed to a day with nothing written, and it is the unit a period average is computed over.

Refeed

A refeed is a planned day or two at maintenance calories or above, usually higher in carbohydrate, placed inside a longer deficit.

Reference values

Reference values are the calories and macros of a plain, unmixed food per 100 g or 100 ml, as published in a standard food composition table.

Restaurant estimate

A restaurant estimate is a calorie and macro figure reasoned out for a dish nobody weighed, from what the dish is, about how much of it there was, and what it was cooked in.

Reverse dieting

Reverse dieting is raising calories in small weekly steps at the end of a deficit, back toward maintenance, instead of returning to full maintenance at once.

RMR

RMR, resting metabolic rate, is the energy a body uses over a day at rest but awake, measured or estimated under less strict conditions than BMR and usually a little higher.

Satiety

Satiety is the feeling of fullness after eating and the length of time before hunger returns, shaped by protein, fibre, water content and the volume of what was eaten.

Saturated fat

Saturated fat is the kind of fat whose molecules carry no double bonds, solid at room temperature, found mostly in animal fat, butter, cheese and coconut and palm oil, and listed on labels as a sub-line of fat.

Scale weight

Scale weight is the number a bathroom scale shows on a given morning, the sum of fat, muscle, bone, water and whatever is in the gut, and the noisiest of all body measures.

Self-monitoring

Self-monitoring is the practice of observing and recording one's own behaviour, and in nutrition it means keeping a food record so that intake is known rather than assumed.

Serving size

A serving size is the reference amount a label's figures are given for, chosen by the producer or set by regulation, and it is often not the amount a person actually eats.

Signed reply

A signed reply is an assistant's answer that marks which of its sentences rest on a tool's result, so that the person can tell the record's facts from the assistant's own words.

Sodium

Sodium is the mineral in salt that labels report either as sodium or as salt, where salt is sodium multiplied by 2.5, and it carries no energy.

Source of a number

The source of a number is where a recorded calorie or macro figure came from: a label, the person who ate, a reference table or an estimate.

Sugar

Sugar, on a nutrition label, is the part of carbohydrate made of simple sugars, whether naturally present in a food or added to it, listed under carbohydrate as "of which sugars".

TDEE

TDEE, total daily energy expenditure, is the estimated number of calories a person's body uses in a day, resting metabolism plus activity.

Thermic effect of food

The thermic effect of food is the energy a body spends digesting, absorbing and storing what was eaten, a share of the day's expenditure that is highest for protein and lowest for fat.

Time-restricted eating

Time-restricted eating is the form of intermittent fasting that keeps all food inside a fixed daily window, commonly eight to ten hours, and leaves the rest of the day without calories.

Tool

A tool, in an assistant, is a named action a service offers to the model, with a description of what it does and the inputs it takes, so that the model can call it during a conversation.

Tool annotation

A tool annotation is a declared property of an MCP tool, read-only, destructive, idempotent or open-world, plus a human title, that a client shows the person before they approve a call.

Trans fat

Trans fat is unsaturated fat whose molecules have been reshaped, mostly by partial hydrogenation of vegetable oils in industrial processing, and it appears on some labels as a separate line.

Trend weight

Trend weight is a smoothed weight, usually a moving average of daily weigh-ins over a week or more, that shows the direction under the daily noise of water and meals.

Under-reporting

Under-reporting is recording less than was actually eaten, whether by forgetting items, guessing portions small or leaving out what felt unimportant, and it is the most common error in any food record.

Undo

Undo is taking back the last change made to a record, so that a mistake costs one sentence rather than a lost day.

Unsaturated fat

Unsaturated fat is fat whose molecules carry one or more double bonds, liquid at room temperature, found mostly in vegetable oils, nuts, seeds, avocado and oily fish.

USDA FoodData Central

USDA FoodData Central is the United States Department of Agriculture's food composition database, the reference most English-language calorie figures for plain foods trace back to.

Waist measurement

A waist measurement is the circumference at the navel or the narrowest point, taken with a tape under the same conditions each time, a body measure that moves more slowly and more honestly than the scale.

Water weight

Water weight is the part of a day-to-day change on the scale that comes from how much water the body is holding, moved by salt, carbohydrate, training and the time of day, rather than from fat.

Weekend effect

The weekend effect is the common pattern of eating noticeably more, and logging noticeably less, from Friday evening to Sunday, so that a week that looks on target from Monday to Thursday is not.

Weekly average

A weekly average is the mean of the daily calorie totals over a week, the figure that smooths a high Saturday against a low Tuesday and says what the week actually was.

Weigh-in

A weigh-in is stepping on a scale at a fixed time under the same conditions, usually in the morning, so that readings can be compared across days and weeks.