Intermittent Fasting, Metabolic Switching and Autophagy
Metabolic switching is not a diet and even in the unlikely event that you do not lose weight, you still benefit from it. It is changing the timing of when you eat for at least two days a week. This change in timing allows your body to switch fuel from using carbs (glucose) for 12 hours followed by 6 hours when it uses fatty acids from the breakdown of fat. This periodic flipping of the metabolic switch creates a adaptive response that has many lasting health benefits independent of weight loss.
Because it was published in the most prestigious and rigorous medical journal in the world (New England Journal of Medicine December 26, 2019) and costs nothing to implement it except spending extra time to educate my patients or in this case, creating a webpage and directing my patients to it, I decided to integrate metabolic switching as a component of my evidence-based medical therapy. I tried it myself - so if you ask "Doc, how do I actually do this?" - click the link below to take you the next page.
Glucose and fatty acids are the two main sources of energy for the cells. After meals, glucose is used for energy, and fat is stored in adipose (fatty) tissue as triglycerides. During periods of fasting, triglycerides are broken down into fatty acids and glycerol. The liver then converts fatty acids into ketone bodies, which provide the major source of energy (fuel) for many organs especially the brain.
Intermittent 5:2 fasting (5 days off, 2 days on) has many benefits that goes beyond weight loss and reduction of damaging free radicals. It improves glucose regulation, increases stress resistance, autophagy and suppresses inflammation.
During fasting, there is a metabolic switch that occurs - from using of glucose as the fuel source to using of fatty acids and ketone bodies, resulting in more efficient energy production and less oxidative stress. In addition to being use as fuel source, ketone bodies have other benefits: they are potent signaling molecules with major positive effects on cell and organ functions. Ketone bodies regulate the expression and activity of many proteins and molecules that are known to influence health and aging.
Intermittent fasting causes on and off metabolic switching which over time results in lasting adaptive responses that leads to increased antioxidant defenses, DNA repair, protein quality control, mitochondrial biogenesis and down-regulation of inflammation. These responses enable cells to remove damage proteins and mitochondria and recycle undamaged molecules (autophagy).
Intermittent fasting improves indicators of cardiovascular health: blood pressure, resting heart rate, LDL and HDL-cholesterol levels, triglycerides, glucose and insulin, insulin resistance and inflammation.
In addition to the heart benefits, there are other benefits - one is preventing or delaying the onset of neurocognitive decline (dementia). It is especially important since there is no effective drug for it.
Here is Dr. Ekberg giving a nice presentation about this New England journal article. Ignore the attention-grabbing thumbnail - this is not just for women who can wear a bikini.
Another important benefit of intermittent fasting
Another important and previously unknown benefit of intermittent fasting is the activation of autophagy for several hours a few times a week.
Intermittent fasting is a challenge especially in the beginning but most of us can do some form of intermittent fasting. You will experience craving for certain food at certain times but with practice and perseverance you can overcome it. Activating some autophagy is another reason to keep on trying.