What is the first nutrient depleted during starvation?

During periods of starvation, the body initially depletes its glycogen stores. Glycogen, which is the stored form of glucose, is primarily found in the liver and muscles. In response to a lack of food intake, the body begins to utilize glycogen for energy to maintain normal metabolic functions as glucose is a critical fuel source for many tissues, particularly the brain.

The depletion of glycogen occurs relatively quickly because it is readily accessible for energy production. Once glycogen stores are exhausted, the body will then shift to utilizing fats and proteins for energy. Therefore, the correct identification of glycogen as the first nutrient depleted during starvation reflects the body's prioritization of available energy sources to sustain function before transitioning to store fat and protein utilization.