"Prolonged starvation" refers to a situation where someone does not have enough food to eat for an extended period of time, which can cause severe hunger and negative health effects. Full definition
Human brains, unique amongst animals, can use ketones as a major fuel source during prolonged starvation, allowing the conservation of protein such as skeletal muscle. (idmprogram.com)
After prolonged starvation, people can die even before their fat stores are depleted, probably due to deficiency of essential amino acids [121]. (nutrientsreview.com)
[1] Amino acid metabolism during prolonged starvation [2] Insulin, glucagon, and catecholamines in prevention of hypoglycemia during fasting [3] Glucagon: The effects of its excess and deficiency on insulin action [4] Renal gluconeogenesis. (perfecthealthdiet.com)