Malnutrition is an abnormal condition caused by deficiencies, excesses or imbalances in energy and/or nutrients necessary for an active and healthy life; if the deficiency or excess continues over time, the person starts to show signs of malnutrition (WHO).

Undernutrition is a form of malnutrition caused by deficiency in energy and/or nutrients. Undernutrition includes growth failure and nutrient deficiencies and can manifest itself in different ways.

Acute undernutrition is a recent, severe weight loss as a results of acute food deprivation with or without illness, also referred to as “wasting”. Acute malnutrition may also result in bilateral edema: fluid retention on both sides of the body.

Chronic undernutrition is an abnormal physiological condition whereby individuals do not consume sufficient food to meet dietary energy and nutrient requirements over a prolonged period of time. In children, chronic undernutrition can result in stunting (growth failure). Stunting is hardly reversible after two years of age.

Overweight and obesity: The other face of malnutrition is the one caused by an excessive energy intake. This type of malnutrition is reflected as overweight and obesity, and it is associated to some chronic diseases like diabetes mellitus type 2, hypertension and cancer.

Micronutrient deficiencies are a lack of vitamins, minerals and/or trace elements required in small amounts which are essential for the proper functioning, growth and metabolism of a living organism. Micronutrient deficiencies can occur when someone is underweight, but also when someone has a normal weight, or is overweight. For this reason, it is also referred to as “Hidden Hunger” (FAO e-learning). A micronutrient deficiency is not always detectable based on a person’s physical appearance, but it can display various symptoms, like night blindness or fatigue.

Nutritional status (undernutrition and overweight) can be determined using measures of weight, height and age. Micronutrient deficiencies can be determined with blood tests amongst others.


FAO. (n.d.). Nutrition, Food security and Livelihoods: Basic concepts. Retrieved from

World Health Organization. (2017, February 6). What is malnutrition? Retrieved from