Going on a calorie restricted diet for a short time shocks your metabolism, taps into fat stores for energy, and helps you see results in a short amount of time. (consumerhealthdigest.com)
When you turn off access to glucose, a primary fuel source derived from eating carbohydrates, the body taps into its own fat stores for energy. (businessinsider.com)
This causes you to have dangerously high levels of ketones (substances occurring when the body uses fat stores for energy) and blood sugar. (drmowll.com)