Fasting has been a part of religious practice for thousands of years. But in the past five years, it received mainstream popularity on the back of animal studies showing that skipping meals had health benefits in overweight people.
I started intermittent fasting following the 16:8 method in 2017. After having changed my diet to eat less breads and pastas, and more protein, fat and vegetables in 2015, I couldn’t eat as often anymore. Plus, I wanted all the health benefits that proponents of fasting claimed — autophagy being the top of that list (You may know my crazy idea by now to live to 200 — or at least to live with the mindset that I will live to 200).
While fasting has an array of benefits, it’s still what you eat that counts.
Autophagy is a metabolic process occurring in starvation whereby the body consumes its own cells. It’s an effective way to remove old and decrepit cells. Autophagy becomes less efficient as we age and sluggish autophagy can allow the inside of cells to gunk up. This can lead to age-related diseases, and to the ageing process itself. In addition to more efficient autophagy, there are other compelling benefits of fasting.
The Power of Fasting
Weight loss. As you are not eating as often — on the 16:8 intermittent fast you only eat within an 8-hour window, and let’s face it, you can only eat so much in one sitting — you typically consume less calories throughout the day, meaning it’s easier to lose weight and maintain a healthy weight range.
Lower blood pressure. Blood pressure is the pressure of your blood on the walls of your arteries as your heart pumps it around your body. Blood pressure increases with alcohol intake, eating salty foods, weight gain, lack of physical activity and as a result of family history. Fasting lowers blood pressure, most likely because when you eat, blood is directed to your stomach and small intestine, at the same time narrowing the blood vessels that are distant from your digestive system, causing your heart to beat faster and harder. Eating less often puts less strain on your heart.
Lower insulin-like growth factor-1 (IGF-1) hormone. This is a hormone similar in molecular structure to insulin. It has growth promoting effects on almost every cell in the body. In addition, it can regulate cellular DNA synthesis. This is a hormone produced in the liver and while it can be beneficial, high levels of it are believed to significantly increase the risks of colorectal, breast and prostate cancer. Low levels are thought to reduce those risks.
Lower inflammation. Inflammation is the body’s response to injury. It is the body’s way of signalling the immune system to heal and repair damaged tissue, as well as protect itself against foreign invaders such as viruses and bacteria. If you are overweight, it is likely you also have inflammation. Fasting reduces the release of pro-inflammatory cells called “monocytes” in blood circulation. During periods of fasting, these cells go into “sleep-mode”.
Lower cholesterol. Cholesterol is a waxy substance found in your blood. Your body needs cholesterol to build healthy cells, but too much cholesterol can increase your risk of heart disease. Regular fasting can decrease your low-density lipoprotein (LDL), or “bad”, cholesterol. After 10 to 12 hours of fasting, the body starts to scavenge for other sources of energy. It pulls LDL cholesterol from the fat cells to use as energy.
Burning fat for fuel. When you fast, the glucose (sugar) in your bloodstream runs out and so-to does glycogen (the storage form of glucose) in your liver. Your liver starts a process called ketosis in which it converts fats into ketone bodies. The liver holds approximately 700 calories worth of glucose and most people burn approximately 70 calories an hour performing everyday activities. That means that the everyday person would burn through their glycogen stores in about 10 hours just going about their day. If you exercise, you will burn through this store more quickly. Fasting allows you to burn through your glucose and glycogen stores and convert to burning fat. In addition to the obvious benefits to weight, burning fat for fuel also has benefits to your health.
Mental clarity. Switching your brain’s fuel from glucose to ketones is a claim that fasters and proponents of the Keto Diet alike say give them mental clarity. There is little research to back this up in human trials; however, there are some animal studies which suggest this. Switching to ketosis stimulates the release of a chemical called brain-derived neutrophic factor (BDNF), which promotes new connections between neurons and stimulates neurons to produce more mitochondria. Mitochondria produce energy in the cell.
There are many benefits to fasting. Which type of fasting is best; we just don’t know. It appears all have their merits. At the end of the day, it appears that you must fast for at least 10 hours to achieve any benefit. And how long? We know that famine is very unhealthy. Longer fasts, such as those that last for 3 days (and in some cases longer), may be okay when they occur only every now and again. Plus, what you eat is of utmost importance.
It would be remiss of me not to point out that fasting can result in an electrolyte imbalance that can make you prone to arrhythmias and problems with the rhythm or rate of your heartbeat. Discuss fasting with your doctor before trying it.
Fasting should also be avoided if you:
- Are pregnant or breastfeeding
- Are a child or teenager
- Have type 1 diabetes
- Have an eating disorder
Have you tried fasting? What benefits did you experience? If you haven’t, what’s stopped you? And if you’re willing to give it a try, what do you see as the most compelling benefit?
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