In recent times, a rather rare and lesser-known form of diabetes (type 5 diabetes) has been discussed, which was officially designated as type 5 diabetes at the IDF Congress 2025 [1].
This is a form of diabetes triggered by malnutrition or undernutrition and has been observed in younger individuals with a very low BMI (below 19 kg/m²). This type of diabetes has been known since 1955 in low- and middle-income countries and is about as prevalent as the human immunodeficiency virus (HIV).

Its origin is thought to be related to protein deficiency in early childhood, resulting in a lower number of beta cells in the pancreas compared to metabolically healthy individuals and causing problems with insulin secretion [2].

This diabetes type is currently (2025) not yet included in treatment guidelines. Based on current knowledge, therapy with very small amounts of insulin combined with oral antidiabetic drugs is the most effective. Insulin dosages comparable to those used in type 1 diabetes treatment may cause hypoglycemia in people with type 5 diabetes because of their high insulin sensitivity.