During the FMD (Fasting Mimicking Diet), our genomes activate autophagy or “self-eating.” Our bodies begin to look for the components that are unnecessary and nonfunctioning. They are selectively broken down and the nutrients they contain are utilized.
For example, Longo (Valter Longo, director of the USC Longevity Institute) measured T cells—the immune system’s defense against cancers and other diseases. At any one time, about a third of your T cells are old and nonfunctioning. So, they’re broken down and utilized for their nutritional content during the FMD.
When you’ve finished the FMD and are eating in modern feast mode, your stem cell processes quickly kick in and replace those missing T cells. So, you have a supercharged fully functioning immune system, perhaps for the first time. This may explain why cancer rates in animals fall after FMD, but there is another possibility.
Our mitochondria are essentially a symbiotic species of bacteria. These aliens within come entirely from your mother’s supply and have their own short circular DNA rings called plasmids. When they are working properly, they communicate with one another and the genome, creating the intelligent energy grid that powers our bodies.
Unlike T cells and other cells, mitochondria replicate through fission, splitting into additional mitochondria in the same way that bacteria replicate. This is called mitochondrial biogenesis and it is critical to life.
Like T cells, mitochondria get old. This is a major problem because mitochondria function like batteries. On one side of an inner membrane is an area of low ion concentration. On the other side is a higher concentration. This difference in ion levels powers the production of the energy molecules our bodies require: adenosine triphosphate.
The problem is that old mitochondria leak. Ions escape and result in the formation of free radicals or reactive oxygen species. Though free radicals play necessary and important biological roles, the unintended production of these molecules is responsible for a great deal of accelerated aging and disease.
Some scientists believe the health benefits of CRON are the result of clearing out old mitochondria through autophagy. Specifically, this process of recycling malfunctioning mitochondria for their nutrient value is called mitophagy.
This view is reinforced by research showing that calorie restriction activates the creation of new mitochondria, presumably to replace those that have been cleared out by mitophagy. This may also explain why short-term FMD does not lead to a loss of muscle tissue, which is an unfortunate side effect of long-term dieting.