What happens in the body when one fasts?

We humans have a strong urge to eat food, but research is increasingly showing that skipping a few meals can be healthy. In fact, many of today's diseases can be traced to our inability to find a natural balance between how much we eat and how much we fast. But why is it so difficult to find that balance?

The body's natural process

When we eat food, the body uses it to create energy. If we eat more than we need at the moment, the excess is stored as body fat. When we then don't eat for a while, the body is forced to use the stored fat for energy. Think of the body as a pantry where you sometimes have to take things out to keep it rotating, just as we have to use stored fat for energy.

If we just put things in the "pantry" without ever taking anything out, stagnation is created. The same thing happens to the body when we eat too often without fasting. It's like just filling a pond without letting the water flow out - the stagnation leads to problems. Similarly, overeating contributes to many of our modern diseases, such as cardiovascular disease, diabetes and high blood pressure.

Why do we eat so often?

A common theory is that we have trained our bodies to rely on frequent meals. Many official guidelines, such as those from the USDA, suggest we eat three meals a day and snacks in between to keep blood sugar stable. But that is not the only reason. In fact, our frequent eating is because our blood sugar levels have become unstable due to our eating habits, especially with the modern diet full of processed foods and sugar.

The body's four hormones that raise blood sugar

The interesting thing is that the body has four hormones to raise blood sugar, but only one to lower it – insulin. This is because, historically, we needed to raise blood sugar more often than to lower it. Here is a brief explanation of these hormones:

1. Glucagon – This hormone is secreted by the pancreas when blood sugar levels are low. It stimulates the liver to convert glycogen (stored glucose) into glucose that is released into the blood to raise blood sugar levels.
2. Cortisol – Cortisol is a stress hormone that also helps raise blood sugar, especially during periods of stress or fasting. It helps the body make glucose available by stimulating gluconeogenesis, which is the process by which glucose is created from non-carbohydrate sources, such as protein.
3. Adrenaline – This hormone, also known as the “flight-or-fight” hormone, is released during stressful situations. It mobilizes rapid energy by releasing glucose and fatty acids from the body's stores to quickly raise blood sugar.
4. Human Growth Hormone (HGH) – Growth hormone increases the breakdown of fat and helps maintain blood sugar levels by reducing muscle glucose uptake, which results in more glucose remaining in the blood for other body functions.

What happens during fasting?

After eight hours without food, the body begins to use a mixture of glycogen (stored carbohydrate) and fat for energy. Glycogen is mainly found in the liver and muscles and lasts about a day. As you fast longer, the body begins to slowly transition from using glycogen to using fat as its primary energy source.

What is Autophagy? – The body's "Self-cleaning"

After about 18 hours without food, a fascinating process starts in the body called autophagy, which means "self-eating". It may sound dramatic, but it is about the body starting to break down and recycle damaged or old cells. During autophagy, cell waste, viruses, bacteria and old blood cells are taken up and recycled to create new resources. It is an important tool for cleansing the body and has been shown to be critical in reducing inflammation and protecting the brain from damage, such as after concussions.

Autophagy is also one of the few processes that can help clean up the nervous system and improve brain health. If you never fast long enough (at least 18 hours), you will never fully benefit from this natural "self-cleaning".

The benefits of longer fasting

After 24 hours without food, the body starts producing ketones, an alternative fuel source for the brain. Ketones are byproducts of fat and can make up to 75% of the brain's energy needs during fasting. At this time, important hormones such as growth hormone and brain-derived neurotrophic factor (BDNF), which help with cell renewal and brain health, also increase.

After 48 hours, the body reaches even higher levels of autophagy and ketone production. Insulin levels continue to drop, which is especially good for those suffering from insulin resistance. At 72 hours, autophagy and ketosis reach therapeutic levels, which can help reverse diseases such as type 2 diabetes, heart disease, and even some forms of cancer.

Which diseases can fasting reduce the risk of?

Fasting has been shown to reduce the risk of several diseases, including:

1. Type 2 diabetes – Fasting improves insulin sensitivity and helps the body regulate blood sugar, reducing the risk of developing type 2 diabetes.
2. Cardiovascular disease – By lowering blood pressure, cholesterol levels and inflammation, fasting can reduce the risk of heart attacks and strokes.
3. Obesity – Intermittent fasting helps with weight loss by promoting fat burning and reducing calorie intake.
4. High blood pressure – Fasting can lower blood pressure and improve vascular health, reducing the risk of cardiovascular complications.
5. Cancer – Research shows that fasting can slow the growth of cancer cells and reduce the risk of certain types of cancer.
6. Neurodegenerative diseases – Fasting stimulates the production of ketones, which protect the brain and reduce the risk of diseases such as Alzheimer's and Parkinson's.
7. Metabolic syndrome – Fasting helps balance blood sugar, reduce excess weight and improve cholesterol levels, reducing the risk of metabolic syndrome.
8. Inflammatory diseases – By reducing inflammation, fasting can relieve symptoms of conditions such as rheumatoid arthritis and Crohn's disease.

Conclusion

Fasting is not just about going without food – it is a way to restore the body's natural balance and promote health. By understanding the hormones that regulate blood sugar and taking advantage of processes like autophagy, we can improve our metabolic health and reduce the risk of many diseases.