Setting the obvious aside, (you know, the not eating bit) let’s take a look at why Dr. Jason Fung believes that fasting offers particular weight loss benefits over and above simple caloric restriction as we continue our ongoing discussion of June’s Diet of the Month, The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting.

When we eat, the complicated process of digestion and absorption kicks off. Food is both mechanically and chemically broken down and then absorbed as it travels along the GI tract. When blood nutrient levels begin to rise, our bodies respond hormonally and metabolically. One particular response Dr. Fung is keen to point out is the insulin response.

Insulin, sometimes known as the ‘feasting hormone,’ is released by the pancreas to deal with the aftermath of eating. Rising blood sugars and excess energy need to be dealt with and insulin is the hormone for the job, shuttling those sugars into nearby cells and triggering the storage of excess energy as fat.

This being the case, Dr. Fung argues that when a person is constantly snacking and stimulating their insulin response, the body is in a perpetual fat storage mode and is never able to tap into stored fat. In other words, eating all the time makes it near impossible to use and lose body fat!

This is where a fasting regimen may prove its weight loss worth. When a person is in a fasting state, the body switches from storing energy to burning it. As circulating and stored sugars are used up, the body needs an alternate (and readily available) energy source, namely, those extra pounds of wiggle you’d like to lose.

So how does the body turn fat into useable energy? During the initial stages of fasting, the body turns to a process called gluconeogenesis (literally, creating new sugar), that enables the body to convert certain amino acids and lipids into much needed glucose. If fasting continues, a state called ketosis eventually results. Lowered insulin levels trigger lipolysis (the breakdown of fats for energy), providing essential fodder for ongoing gluconeogenesis as well as protein synthesis. Ketone bodies are formed to supply vital energy for the brain. Put simply, when you don’t eat, your body will eventually break down and use up proteins and body fat to get what it needs.

Ultimately, Dr. Fung argues that by halting (at least temporarily) the constant stream of energy from food, fasting allows a person to readily tap into stored body fat and shed pounds.

So what about potential muscle loss? And the dreaded ‘starvation mode’ and sluggish metabolism attributed to low calorie diets? What about HUNGER?? Next time, we’ll look at Dr. Fung’s chapter on fasting myths and why it might not be as hard as you think to begin your own fasting regimen for health and weight loss!