In recent years, many research results have been published on the positive effects of fasting. Fasting helps reduce inflammation, stabilize intestinal health, reduces the risk of chronic diseases, especially insulin resistance and diabetes 2, reduces oxidative stress (aging), etc. (Asprey, 2021, S. 28).
Here is more info about how to get started.
There are many different variants of fasting, which have different - positive - effects on the body:
This option is possible for most people and can be implemented in everyday life. With intermittent fasting, you eat within a time window of 8 hours and fast for 16 hours. For most people - especially with family - it is easiest to eat dinner relatively early, at the latest at 19h. People skip breakfast and have only a cup of coffee or tea and maybe a small snack at 11 am. The first real meal is lunch. My ideal scenario would be to have a big breakfast at 11h and dinner at 17h - so two meals a day. Unfortunately, this is totally family incompatible. This means you’ll have to find your rhythm that suits you!
In the fasting phase, the available glucose in the blood is used up after about 12 hours. The pancreas produces less insulin. The body now uses the glycogen stored in the muscles and the liver. Most people try to incorporate intermittent fasting several days a week.
One meal a day
If you eat once a day, you fast for about 24 hours. After 16 hours of fasting, the body begins to switch from glucose (sugar) to fat burning. Fat burning (ketosis) is a very complex bio-chemical process, which you can read about in Dave Asprey's book on p. 71 (Asprey, 2021). There are different opinions on how often you should take this 24-hour fast. Longevity guru David Sinclair does it every day. Dave Asprey writes that sustained 24-hour fasting negatively affects your hormones, sleep quality, and health. Mindy Pelz also recommends that women adjust their fasting to their menstrual cycle. More info on 24 hr fast.
Fasting 36-120 hours
After 24 hours, the body burns fat (ketosis) instead of sugar, or the body itself turns fat snips (ketones) and amino acids (components of proteins) into glucose. After this time, less of the hunger hormone ghrelin is produced. As toxins are stored in fat, they are released from the fat reserves during longer fasting periods. This can give you a so called “keto flu”, feeling weak and not very good. It is very important that the body detoxifies during a longer fast. This means that it is important to sweat, continue to have regular bowel movements, and sleep well. When the "crisis" is over, most people feel surprisingly fit and not hungry. After 36 hours, so-called autophagy begins, in which the body begins to recycle cells that the body no longer needs. Typically, the first starts “eating” what it no longer needs. Now it becomes increasingly important to break the fast with a nutrient-rich meal and not overload the body.
There are - you guessed it - very different opinions about extended fasting. As already mentioned, the toxins are released from the fat reserves, which is why detoxification is very important during this time. However, most experts agree, that healthy people would benefit from a 5-7 day fast.
When not to fast
If you have health problems, prolonged fasting can be harmful. Therefore, people with pre-existing health conditions should consult with their doctor and ideally fast under professional supervision.
In addition, it is recommended to heal the gut before fasting more than 16 hours, in order to ensure effective detoxification through the intestines. (Anne Fleck, 2021, S. 244)
Women should adapt their fasting protocol to their cycle. Mindy Pelz has a few podcasts about this issue on her website, for instance.
If you are curious about fasting and want to know more about the science behind fasting and particularly about women and fasting I strongly recommend you visit Mindy Pelz Website. She truly is a woman on a mission! https://drmindypelz.com/
Dave Asprey has written an easy to read book about fasting and fasting kacks: Asprey, D. (2021). Fast this way.Thorsons.
Anne Fleck, D. (2021). Energy. dtv.