Badly or poorly nourished.
When they finally found the children in the locked cabin, they were pale and malnourished but unharmed.
Malnourished people can be found in all types of societies. Famine and poverty are only two of the common causes of malnutrition. In more affluent societies, it is often the result of poor eating habits. Any diet that fails to provide the nutrients needed for health and growth can lead to malnutrition, and some of the malnourished are actually fat.