Adipose tissue ~ body fat
In our bodies, the two main energy sources are carbohydrates (via glucose) and fat (via fatty acids). Generally, after we eat a meal that contains a mix of nutrients, glucose is used for energy and fat is stored in adipose tissue.
Adipose tissue ~ or body fat ~ produces hormones which influence several important functions including glucose and lipid metabolism, blood coagulation, insulin sensitivity, blood pressure, and steroid hormone modulation.
Excessive adipose tissue can negatively affect health through insulin resistance, abnormal blood lipids, and even increased cardiovascular disease risk.
During a fast day, the body flips from an energy-storing state to an energy-burning state. The body will use the fat for fuel causing the fat cells to shrink in size.
As fat cells decrease in size, so too does the amount of signaling molecules or hormones produced.
In addition to sustainable weight loss, this reestablishment of normal endocrine function can be immensely beneficial for health including decreasing insulin sensitivity and the molecules that induce inflammation.