macronutrient

Macronutrient is a class of nutrients required in relatively large amounts by organisms to support energy production, growth, and the maintenance of bodily functions. In human nutrition, the primary macronutrients are carbohydrates, proteins, and fats. Water is essential and consumed in large quantities, but it is usually treated separately from the macronutrient group. Together, macronutrients supply energy and provide the building blocks for tissues, enzymes, hormones, and cell membranes.

Carbohydrates supply about 4 kilocalories per gram and are the body’s main energy source. They include simple sugars and complex starches, as well as dietary fiber that affects digestion and metabolic responses. Dietary guidance often emphasizes whole grains, fruits, vegetables, and legumes as preferred carbohydrate sources.

Proteins provide about 4 kilocalories per gram and are made up of amino acids. They support tissue growth and repair, immune function, and the synthesis of enzymes and hormones. Essential amino acids must be obtained from the diet. Good protein sources include lean meats, dairy products, legumes, and grains.

Fats provide about 9 kilocalories per gram and include saturated and unsaturated fats. They supply concentrated energy, aid in the absorption of fat-soluble vitamins, and contribute to cell membranes and hormone production. Essential fatty acids, such as omega-3 and omega-6, must be obtained from the diet. Common sources are oils, nuts, seeds, and fatty fish.

Dietary guidelines typically present macronutrient ranges, such as carbohydrates 45–65% of energy, protein 10–35%, and fat 20–35% of daily energy (AMDR). Individual needs vary with age, sex, activity, and health status, but a balanced intake emphasizes variety and whole foods while limiting added sugars and saturated fats.