Malnutrition refers to deficiencies, excesses, or imbalances in the energy, macronutrients, or micronutrients that a person obtains. This is either because their diet is lacking or because their body is not able to fully absorb the nutrients from the foods eaten, e.g. due to illness. Malnutrition is an umbrella term that includes overnutrition (an excess of food energy), undernutrition (a lack of food energy and macronutrients such as protein), and micronutrient deficiencies (insufficient micronutrients such as iron, vitamin A or iodine).