Fasting is getting trendy now and while it helps with weight loss, it has many benefits that have been largely overlooked. It is one of the most powerful yet most under-utilised medical therapies there is. Fasting is the body's own natural stem cell therapy, rejuvenating and regenerating the body. On top of that, it's totally free!
The role of fasting in human evolution
The lifestyle of hunter gatherers has over some hundred thousand years shaped the genes we have today. For all the new lifestyles that came after the stone age in the last few thousand years - starting out from agriculture and cultivation of grains as an important source of food, there was simply not enough time for our genes to adapt. In essence we still carry the same gene pool our ancestors had some 10,000 years ago.
If you have a human generation every 20 years, you have 500 generations in 10,000 years. From an evolutionary standpoint this is a very short time. As a comparison, E.coli bacteria can grow a generation in twenty minutes when conditions are favourable, that makes 72 generations in a day and 500 in a week! A busy family of bacteria this way produces the same number of generations in a week that humans need 10,000 years for!
While we still carry more or less the same genes as our paleo-ancestors, we've drastically changed our environment and the way we live, especially in the last few hundred years and quite dramatically in the last fifty.
Our ancestors didn't have a fridge and food at their fingertips. It was natural for them to have cycles of feast and famine and going without food for a few days was not uncommon at times. There were also seasonal changes with ample food in late summer and autumn and less to eat in winter.
In contrast to these natural cycles we've mutated to a mostly sedentary society spending long hours sitting in front of computers, smartphones, tablets and TV. We tend to eat and snack frequently. Fifty years ago the majority had three meals a day, without energy bars and other snacks in between.
Constant eating is a big and long term problem for our health. Did you know that at any given time, the body tries to limit the amount of sugar that is circulating in our entire bloodstream to around 5 grams or the equivalent of 1 tablespoon? A higher blood sugar level is toxic over time, as any diabetic will tell you. With every bottle of soda or even fruit juice - organic or not - you will keep your pancreas pretty busy excreting all the insulin that is necessary to get the sugar out of the blood and into the cells. When we constantly stressing our system with too much sugar, there's a high likelihood of developing an insulin resistance, leading first to pre-diabetes and eventually to a full blown type II diabetes.
But it's not only the frequency of meals and our high carb diet. The nutrient density of our foods has constantly declined over the past 100 years, while the number of chemicals has steadily increased. Pesticides, herbicides, preservatives and environmental toxins are found in the food we eat, the water we drink and the air we breathe.
This all puts a strain on our gut, the immune system and our detoxification pathways and in the end triggering and increasing levels of inflammation in the body.
When we fast, we give our digestive system a break and the body a chance to heal and regenerate.
As already mentioned, our ancestors fasted naturally. When we turned into an agricultural society, religions took on traditions to fast. Almost all religions have some sort of fasting incorporated into their rituals.
Interestingly, no stories were handed down about the hardship of fasting. It was a natural thing, one the bodies of our ancestors were accustomed to. Do you think they got physically weak and dizzy when they did not have food for some days? No, quite the contrary. They had to be alert and physically strong to hunt their prey despite an empty stomach. And there are ample reports about the clarity of mind you gain when fasting.
This is in stark contrast to our modern society’s belief that we cannot perform and function without constant supply of food. Many say they feel miserable when they don’t eat. In fact, this is because we evolved into carb-junkies.
Burning sugar vs fat
Our bodies are designed to burn either carbohydrates (i.e. sugars) or fat for energy. The master-switch that flips the fuel source from carbs to fat, is insulin. When insulin is high, which it is in the presence of excess blood sugar, the little powerhouses in our cells - the mitochondria - will burn sugar. Only when insulin is low enough, will mitochondria switch to burning fat.
Doesn’t our body prefer burning sugar? No, it's a choice made out of necessity. Because high blood sugar is toxic to our body, it is the cells first priority to get all the abundant sugar out of the bloodstream into the cells. In the cell, all the sugar needed for energy is handed down to the mitochondria, where it is burned. Excess sugar, which is not needed, is converted to fat and stored in fat cells for later use.
Because today with our standard diet we deliver our bodies a constant stream of food supply rich in carbohydrates, we never touch our fat storage. It's not the dietary fats that make us obese, it’s the excess carbohydrates.
On top of making us fat, carbohydrates are also the dirtier fuel source. In comparison to fat, burning carbohydrates produces around 40% more ROS (reactive oxygen species) and free radicals which leads to more inflammation. Burning fat is a cleaner fuel alternative for our body and reduces inflammation.
The low fat era that took off in the 1980s, led us to lower the fat content in our diets by increasing our intake of carbohydrates (through bread, cereals, energy bars, more fruits, etc.). Ironically, this "leaner", carb centric diet is one of the main drivers of today's obesity epidemic.
How our bodies respond to fasting
While ancient societies and even our ancestors a few generations ago had the metabolic flexibility to naturally switch between burning sugar and fat. Now that we are constantly staying in the state of carb-burning, we’ve lost that flexibility.
This is one of the two main reasons why people experience flu like symptoms or headaches the first few days on a fast or when switching to a low carb ketogenic diet. The body has to re-learn the ability to produce all the enzymes needed to burn fat as energy.
The other reason to experience symptoms might be higher toxic levels in our bodies from environmental exposure. Toxins that are not excreted will preferably get stored in fat cells. When accessing our fat stores in a fast, those toxins get released into the bloodstream. That is why it is a good idea to support the excretion of these toxins through the urine and stool during a fast. The first is supported by ample intake of water, the latter by supporting the peristaltic motion in the intestine. The addition of electrolytes or salt to the drinking water can further help.
Benefits of fasting
When we enter the state of fasting, remaining carbs will be used up. The body will then switch to burning fat. At the same time the metabolic rate goes up, not down as happens in a state of caloric restriction (diets with low calorie intake). This leads to weight loss.
Freeing up energy
In fact, up to 50% of our energy is required to digest food. In a fast, this energy is freed up from the digestive process and can now be used to heal and regenerate. The body knows best where healing is needed most.
After 24-36 hours sick and weakened cells will - through processes called apoptosis and autophagy - be driven into cell death, taken apart and recycled into new cells. No worries, this is a completely natural process. An average human adult loses 50 to 70 billion cells each day through apoptosis. This rate is strongly increased by fasting.
Stem cell therapy
The next step in the fasting process is sharp increase in stem cell production and activation. The number of new stem cells and the level of HGH, the human growth hormone, significantly surge during days 3-5 of a fast and then afterwards decline again. Newer research has shown, that during that time of increased stem cell generation a huge amount of new white blood cells are produced, thereby strengthening the immune system.
Additional effects of fasting
Besides burning fat, weight loss and an increased immune system, fasting has a lot of additional health benefits, from reducing inflammation, rebalancing the gut microbiome and hormones, protecting the brain from adverse changes associated with Alzheimer's, Parkinson's and other neurological diseases, reducing the risk of cancer and decreasing the rate of ageing and up-regulating the processes of cell maintenance and repair.
No wonder Paracelsus called fasting "our best remedy and our inner doctor". And best of all - it doesn’t cost a thing!
How to deal with hunger on a fast
Hunger comes and goes in waves around your normal meal times. It is best to drink water when a hunger feeling comes up. This will stretch your stomach and thus decrease ghrelin, the hunger hormone. Contrary to belief, the hunger feeling will not continuously rise. Two hours after your normal meal time, the ghrelin level and with it the hunger feeling will be the same, no matter whether you had something to eat or are fasting. The longer you fast, the more the feeling of hunger will decrease.
In case you are new to fasting, I highly encourage you to educate yourself about fasting and if you have a medical condition, talk to a doctor experienced in fasting. A good way to start for beginners is to do a bone or vegetable broth fast. This will give you some nutrients and electrolytes and is also filling.
When to stop a fast
There is a very distinct difference between fasting and starving. You can break a fast at any time. Listen to your body. If symptoms are getting too strong, simply stop the fast and restart eating. Just go slow after a fast. Don't break a fast with a feast. After a fast, start with healthy food that is easy on the stomach, for instance steamed vegetables.
No big deal that you stopped early. You can try again anytime. With each fasting cycle it will get easier for the body to switch to the fat burning mode.
Experiment & choose what works for you
There are many types of fasting. Do your research to find a system that works for you.
If you are not yet ready to go for a full day of fasting or a multi-day fast, you could simply try what happens when you skip a meal and drink some water instead. Then in a next step you could restrict your eating window to 12 hours, and eventually to 10, 8 and 6 hours. This is called intermittent fasting or time restricted eating. Most people incorporate intermittent fasting into their daily routine by skipping breakfast.
Then in a next step you could try to fast for a day, for instance from dinner to dinner. If you are comfortable with it, you can increase to a 36 hour fast from dinner to breakfast 1.5 days later.
Educate yourself, but don't over-engineer and complicate things. You could start with reading Dr. Jason Fung's book "The complete guide to fasting" or his "Intermittent Fasting for Beginners".
Fasting is the most powerful "biohack" I've come across. There is no better way to rejuvenate your cells, strengthen your immune system and boost healing while at the same time increasing your energy and sharpening your focus. Whether you’re a seasoned faster or just starting out, I encourage you to make fasting a part of your regular health regime.
With best wishes for your health,