Nutrition & Calorie Glossary

Calorie

A calorie is a unit that measures the energy food and drinks provide to the body, usually expressed in nutrition as kilocalories (kcal). It comes from a food's protein, carbohydrate, and fat content, and the daily balance between calories consumed and burned is the basis of weight change.

Macronutrient

A macronutrient is one of the three main groups of nutrients the body needs in large amounts for energy and core functions: protein, carbohydrate, and fat. Each provides a different number of calories per gram (about 4 kcal for protein and carbohydrate, about 9 kcal for fat) and together they form the building blocks of a balanced diet.

Protein

Protein is a macronutrient made of amino acids that the body needs to build and repair muscles, tissues, and enzymes. It provides about 4 calories per gram, with meat, eggs, legumes, and dairy as major sources, and it often stands out in meals because it tends to increase the feeling of fullness.

Carbohydrate

A carbohydrate is a macronutrient that serves as the body's fastest and primary source of energy, found as sugars, starches, and fiber. It provides about 4 calories per gram, with bread, rice, fruit, and legumes as major sources, and it is largely converted into glucose when digested.

Dietary fat

Dietary fat is the most energy-dense macronutrient at about 9 calories per gram, playing a role in cell structure, hormone production, and the absorption of certain vitamins. It comes in saturated, unsaturated, and trans forms, with olive oil, nuts, fish, and butter among its common sources.

Fiber

Fiber is a type of plant-based carbohydrate the body cannot digest, supporting digestive health while increasing the feeling of fullness. Found in vegetables, fruit, legumes, and whole grains, it contributes very few calories and is subtracted from total carbohydrate when calculating net carbs.

Basal metabolic rate (BMR)

Basal metabolic rate (BMR) is the minimum number of calories the body burns at complete rest to sustain vital functions such as breathing, circulation, and cell repair. It makes up the largest share of total daily energy expenditure and varies from person to person based on age, sex, height, and body composition.

Total daily energy expenditure (TDEE)

TDEE (Total Daily Energy Expenditure) is the total number of calories a person burns in a day, including basal metabolism plus all movement, exercise, and digestion. It is estimated by multiplying basal metabolic rate by an activity level and serves as the starting point for maintaining, losing, or gaining weight.

Calorie deficit

A calorie deficit occurs when you burn more calories than you consume, which generally leads to weight loss as the body draws on stored fat for energy. It can be created through diet, more activity, or a combination of both; a sustainable deficit varies by person, and extreme restriction is not advised.

Calorie surplus

A calorie surplus occurs when you consume more calories than you burn, which generally leads to weight gain as the excess energy is stored. A controlled surplus can be used by those aiming to build muscle, and whether the result is stored as fat or muscle depends on nutrition and exercise.

Calorie density

Calorie density is the amount of calories a food contains per gram or unit of volume; vegetables and fruit are low, while fatty and sugary foods are high. Because low-density foods offer a larger portion for the same calories, they generally keep you full for longer.

Glycemic index

The glycemic index (GI) is a value on a 0-100 scale that shows how quickly a carbohydrate-containing food raises blood sugar. High-GI foods such as white bread and sugar raise blood sugar rapidly, while low-GI foods such as legumes and whole grains produce a slower, steadier rise.

Saturated fat

Saturated fat is a type of fat that is usually solid at room temperature and found mainly in red meat, butter, full-fat dairy, and some tropical oils. Health authorities recommend limiting excessive intake, and keeping it to a small share of daily calories is generally advised.

Trans fat

Trans fat is a type of fat created by the partial hydrogenation of liquid vegetable oils, found mostly in some packaged snacks and fried foods. It is considered the least healthy type of fat and is restricted in many countries, so avoiding it as much as possible on labels is recommended.

Satiety

Satiety is the feeling of fullness and reduced hunger after eating, and it determines how long a meal keeps you satisfied. Foods rich in protein, fiber, and water with a low calorie density generally provide stronger satiety and can make portion control easier.

Portion

A portion is the specific amount of a food eaten in a meal, and it directly determines the total calories you take in from that food. It can differ from the 'serving size' printed on packaging, and estimating portions accurately is one of the most critical steps in calorie tracking, which photo-based tracking can make easier.

Net carbs

Net carbs are the amount of carbohydrate that affects blood sugar, found by subtracting fiber and, in most cases, sugar alcohols from a food's total carbohydrate. They are used especially by people following low-carb eating patterns and are always less than or equal to total carbohydrate.

Water weight

Water weight is a temporary change on the scale caused by excess fluid held in the body, and it does not reflect a true change in fat. It can fluctuate from day to day due to factors like salt intake, carbohydrate intake, hormones, and exercise, so short-term swings on the scale usually do not mean fat loss or gain.

For informational purposes only — not medical advice. If you have symptoms or a medical condition, consult a doctor.