Malnutrition can be developed due to insufficient intake of macronutrients (protein, carbohydrates and fats), increasing energy needs in the acute illness due to malabsorption - insufficient utilization of nutrients that enter through food or increased loss of nutrients, as a result of complications due to primary disease or a combination of the two or more of the mentioned factors as well as various diets and conscious or unconscious starvations of bodies.

They are indispensable ingredients in human nutrition. Their role is very important for the proper functioning of the body. Proteins are composed of amino acids in the body and participate in the construction of tissues, hormones, and enzymes. Proteins (meat, eggs, fish) are degraded in the body into amino acids. 

They represent the primary source of energy. Moderate amount of carbohydrates is essential in the daily diet. If eaten moderately (rotated), they promote health while their excessive use can lead to chronic non-communicable diseases (HND), diabetes, obesity, cancer and cardiovascular disease.

They have the highest energy value of all the nutrients. There are saturated (pork, tallow, butter) and unsaturated, monounsaturated (olive oil, almonds, hazelnuts) and polyunsaturated fats (flax, fish, chia seeds).

Vitamins and minerals are found in food used in the daily diet. They are involved in metabolic processes, provide better immunity, formation of blood and cell membranes, activity of heart muscle, brain development. Together with a number of enzymes, vitamins and minerals ensure proper functioning of the body.