When John doesn't eat enough carbohydrates to satisfy his body's need where will his body get the needed carbohydrates?

When John doesn't consume enough carbohydrates, his body will begin to break down stored glycogen, primarily found in the liver and muscles, to meet its energy needs. Once glycogen stores are depleted, the body can also convert proteins from muscles and fats into glucose through gluconeogenesis to provide the necessary energy. This process helps maintain blood sugar levels and supply energy for vital functions. However, relying on these alternative sources can lead to muscle loss and other metabolic issues over time.