The Transition to Ketosis During Fasting

The Transition to Ketosis During Fasting

As your body depletes its glycogen stores during fasting, it produces ketones from stored fat. Ketones are an alternative fuel source that can be used by your brain and other organs when glucose is not available.

This process, known as ketosis, is a natural adaptation that allowed our ancestors to survive periods of food scarcity. Today, many people intentionally induce ketosis through fasting or a ketogenic diet to improve their health and lose weight.

Glycogen Depletion and Ketone Production

During the first 12 to 24 hours of fasting, your body uses up its glycogen stores and breaks down fat for energy. This process is known as lipolysis, resulting in the production of free fatty acids and glycerol.

As fasting continues, your liver begins to convert these fatty acids into ketones, which your brain and other organs can use for energy. This process is known as ketogenesis, and it typically begins around 12 to 24 hours into a fast.

• Fasting results in decreased glucose and insulin levels, leading the body to utilize excess glucose and glycogen reserves.

• After glycogen depletion, about 40% of fat is used for ketone production within 12 to 72 hours.

• Prolonged fasting leads to adaptation into a state of ketosis, where the body efficiently uses ketones and fat for energy.