Researchers at the National Institute of Aging in Baltimore have reviewed the literature and performed studies to indicate the positive effects of fasting on overall brain health. Professor Mark Mattson, who the head of the Institute's laboratory of NeuroSciences, made it clear that these benefits were not just related to calorie restriction but instead to intentional periods of intermittent fasting (1).
I
2 Major Physiological Phases: Building and Cleansing
Eating stimulates the body to go into building phase where we are anabolic in nature and store both nutrients and toxins. This phase is essential for building new cells and tissues and store nutrients for times of scarcity. This building phase of physiology is predominately led by the hormone insulin.
Fasting for more than 6 hours begins the cleansing phase. The cleansing phase is catabolic in nature in that it tears down old damaged cells. This process turns on brain autophagy, or “self-eating,” in where the cells recycle waste material, regulate waste products and repair themselves. These genetic repair mechanisms are turned on through the release of human growth hormone (HGH).
Intermittent fasting is one of the most powerful modalities for reducing inflammation, boosting immunity and enhancing tissue healing (2, 3, 4). This is one of the reasons why many people feel nauseated when they have infections. This innate mechanism is the body’s way of influencing us to fast so it can produce the right environment to boost natural immunity.
Just wanted to say that Fasting Boosts Human Growth Hormone (HGH)
HGH is known to create physiological changes in metabolism to favor fat burning and protein sparing. The proteins and amino acids are utilized to improve brain and neuron processing. They also repair tissue collagen which improves the functionality and strength of muscles, tendons, ligaments, and bones. HGH also improves skin function, reduces wrinkles & heals cuts and burns faster (5, 6, 7, 8).
Researchers at the Intermountain Medical Center Heart Institute found that men, who had fasted for 24 hours, had a 2000% increase in circulating HGH. Women who were tested had a 1300% increase in HGH (9). The researchers found that the fasting individuals had significantly reduced their triglycerides, boosted their HDL cholesterol and stabilized their blood sugar.
The Dance Between Insulin and HGH to Govern Metabolism:
HGH and insulin are opposites in function. HGH is focused on tissue repair, efficient fuel usage and anti-inflammatory immune activity (10). Insulin is designed for energy storage, cellular division and pro-inflammatory immune activity (11).
Insulin is the dominant player in this game. When conditions demand an insulin release (carbohydrate intake), HGH is inhibited (12, 13). Additionally, too much protein or fat may not stimulate insulin but they will inhibit HGH release.
Studies have indicated that the disruption of neuronal autophagy results in accelerated neurodegenerative states throughout the brain (14). Elevated circulating levels of insulin reduce the amount of neuronal autophagy and cause metabolic problems as well as accelerated degenerative states (15). Bouts of intermittent fasting are essential for the brain to clean itself up and drive new neurons and communication lines for optimal function (16).
Fasting and Exercise:
The cleansing phase also acts like a slinky that is being spring-loaded for when the body moves into the building stage. It provides a sort of pre-load that allows the body to adapt in an incredible manner when it goes into the building phase. This enhances the neuronal connections and improves brain function.
Experts believe the intermittent fasting puts the brain cells under mild stress that is similar to the effects of exercise on muscle cells. The stress causes them to adapt and get more energy efficient (17). The body recovers from intense exercise through both the building and cleansing phases.
BDNF levels govern the formation of new neurons and the development of synapses and various lines of communication within the brain. Higher levels of BDNF lead to healthier neurons and better communication processes between these neurological cells (18). Low levels of BDNF are linked to dementia, Alzheimer's, memory loss and other brain processing problems (19).
Research has shown that bouts of fasting have a great anti-inflammatory effect on the entire body (20, 21, 22). Sufferers from asthma have shown great results as have preliminary reports on individuals with Alzheimer's and Parkinson's (23). Mattson and colleagues are preparing to study more details about the impact of fasting on the brain using MRI technology and other testing.