Intermittent fasting or intermittent fasting - terms that have slowly but surely established themselves in our society. Longer fasting, for example in a therapeutic fasting regimen, was already known, but the trend of interval fasting only emerged in recent years. Basically, it's about regularly incorporating smaller phases of fasting into your everyday life. This is said to have positive effects on health, performance and concentration and to help you lose weight. However, what the physiological reason is related to metabolism is rarely found in the descriptions. This will now be examined in more detail here in order to refute or possibly question the touted positive effects.
What are the benefits of intermittent fasting?
Part-time fasting in a wide variety of variants, which are explained in more detail below, are said to have many advantages:
Intestinal health is optimized through the rest phases, chronic inflammation is reduced and the body detoxifies many pollutants during this time. This allows the liver and kidneys to focus on binding and excreting toxins and are not burdened with substances from food intake at the same time. The regeneration and renewal of cells also takes place during this intermittent fasting instead of. This is called a self-healing process of the body. It's supposed to be that cells moreover, even rejuvenate and at Lose weight support.
What does intermittent fasting mean? > Definition of intermittent fasting <
Intermittent fasting In comparison to therapeutic fasting or alkaline fasting, it is something that you incorporate into your everyday life as a fixed, long-term routine. It's usually about 12 to 24 hours in which no calories are consumed. However, there are minor exceptions, which will be discussed in more detail in the various methods. By definition it's about intermittent fasting primarily about when to eat and not what 1 . However, this philosophy is not recommended here, because if you combine a healthy diet with fasting, the effect is likely to be even stronger. And even though fasting has many health benefits, the body still needs the right macro and micronutrients to work well.
As is often the case with nutrition topics, the term intermittent fasting also comes from English “Intermittent Fasting” and was literally translated into German “intermittent fasting” translated. Some of the other names already mentioned, such as short-term fasting , intermittent fasting , Partial fasting and Part-time fasting They all mean the same general term for the different methods.
Instructions for intermittent fasting – when should you fast? Who is fasting for?
Intermittent fasting According to a hypothesis from the theory of evolution, lies in our genes, which have not changed much in this regard since prehistoric times. It is assumed that our bodies are designed to withstand long periods without food, because back then there were not a supermarket on every corner and sometimes there was simply no food 2 . That's what happens Fast actually suitable for almost everyone. However, people who have certain illnesses and are taking medication should be careful. Even if Short-term fasting For many of you, this could even minimize your problems, you should first talk to your doctor about it. It would even be an option for diabetics, as fasting can improve insulin sensitivity, but aspects must be taken into account here that a doctor should clarify.
Women should generally be shorter fast than men, due to hormonal conditions 12-14 hours are often enough and more would often be counterproductive as too many stress hormones can be produced. For men it should be at least 16 hours, as the desired processes in their metabolism come into effect a little later and their body is more resistant to stress.
Pregnant women should not fast because they need regular food intake to provide their child with nutrients.
For all methods, bedtime is defined as Lent used because people don't eat or drink there anyway. Since sleep usually lasts 6-8 hours, the missing time is used immediately after or before - or both. For example, you have your last meal in the afternoon and then the next one in the morning the following day. Or you can eat something in the evening and fast until midday the next day.
How long should you fast?
How long you should fast depends on the respective method. This should be selected individually and adjusted if necessary. Basically, however, the fasting period depends on gender, general health, stress level, hormone release and experience. Beginner should at Intermittent fasting Start more defensively and get to know your body to find out which method is the right one in the long term. It's best to start with 12-14 hours, starting at 6 or 7 p.m. the day before.
How often do you do that? Fasting phases per week depends on the method and personal possibilities and needs. Basically: the shorter the Lent , the more frequent should be fasted become. So with 12/12 it makes sense to fast for 12 hours a day, other methods already specify that, for example, two full days per week be fasted.
Lose weight through intermittent fasting
Especially those who want to lose weight will notice that intermittent fasting are very effective in many cases. A study with mice proved that what was mentioned there “Time-Restricted Feeding” allowed the animals to remain slim even though they received the same amount of calories as the control group, which always had to eat. The fasting Mice were only given food at night when it was dark and not when it was light during the day. So they fasted for 16 hours a day. The mice that were constantly eating became obese, resistant to satiety hormones, had chronic inflammation and poor liver function tests, and also developed insulin resistance. None of these diseases occurred in the intermittently fasting mice; on the contrary: they were all perfectly healthy and, above all, slim 12 .
Unfortunately, there are currently no such studies on humans because nutritional topics take a very long time and the topic is still too current for that. However, there are many practical examples and enough physiological explanations as to why Intermittent fasting also has such positive effects for us:
As the digestive tract is emptied, hormonal signals are changed. Because the blood sugar level drops without glucose absorption via the intestine, insulin secretion is reduced. Insulin is the hormone that promotes sugar absorption into cells. Here: More on the topic Blood sugar .
The hormones glucagon and adrenaline, which promote the movement of stored sugar into the bloodstream signaling, are increasingly released so that the cells are supplied with energy 2 . Furthermore, fat reserves are released, which also serve as an energy source, and other processes that draw energy from amino acids begin. After just 12 hours, ketone bodies are also used. These serve as a substitute for sugar because some body cells cannot use fatty acids as energy sources 8 .
Autophagocytosis – intelligent cell cleaning
Intermittent fasting promotes autophagocytosis 11 . This is a form of programmed cell death in which damaged cells infected by pathogens are destroyed and their components are then converted into energy sources and used. So it's a kind of the body's own recycling process. It is somewhat unclear when this state begins; various sources report the onset of autophagocytosis after 12, 14 and 16 hours 10,11 . One can probably assume that it depends on the individual, as already described above in the text.
The methods – models of intermittent fasting: 12/12 – 14/10 – 16/8 – 20/4 – 24/0 – 5/2
- 16/8 Intermittent Fasting is currently the most popular method. Here, food is abstained before 16 hours. As already mentioned, for men this is usually the minimum fasting time to achieve the desired effect. It could also be considered for very fit and stress-resistant women.
- 14/10 fasting works on the same principle and is the most commonly recommended method for women. Then you fast for 14 hours, that's how it will be Breakfast late or eaten dinner early.
- 12 hour intermittent fasting is a good starting method that is suitable for almost everyone. As mentioned, this form of short-term fasting is best done every day. Here the effect is actually strongest if the fasting phase is at least 3-4 hours before Sleep begins. This is because during this period the release of the sleep hormone melatonin begins, which activates a gene that reduces insulin release5. As a result, when you eat shortly before sleeping, your blood sugar increases more and for longer, which has negative effects on sleep quality and hormone secretion as well as weight loss.
- Intermittent fasting of 20 to 24 hours is already very advanced and less relevant for many, as these forms require a stable stress and hormonal system and cannot always be easily integrated into everyday life. Long fasting can also be counterproductive for people who do a lot of exercise.
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The 5/2 method of fasting is an extended form of the latter method. Here you eat everything you want 5 days a week and only consume 500-600 calories two days a week (whether spread out or consecutively). This can be very efficient in losing weight, but it poses the same problems or risks as the 20/4 and 24/0 method .
You can do this rather than one diet and these are usually not sustainable.
What is allowed during intermittent fasting? Coffee, tea and co.
There are different opinions on the subject of coffee and small amounts of calories. At the 5/2 method A daily calorie allowance of 500-600 kcal is allowed, which is why misunderstandings often arise:
For the remaining methods, many people understand it to mean, for example, a Bulletproof coffee , which contains fat and collagen (protein), is allowed to be consumed. However, that does no sense , because this already stimulates the intestines too much.
In principle, during the For intermittent fasting, always drink water with a dash of lemon, lime and a little rock salt, as well as unsweetened tea, if necessary with fresh mint be drunk.
Coffee Although it has a small effect on hormones, it is still popular when fasting due to its antioxidants, insofar as it is drunk black . Especially when the intestinal cells are repairing themselves in the resting phase, Just one shot of milk is counterproductive as it potentially contains allergens and fat 13 .
Who in the Lent sports makes, can also be a portion of amino acids drink while doing it. These should be sugar-free and no additives contain. Because amino acids are already broken down proteins, the intestine has no work to do and here too the fasting-inhibiting reactions are so minimal that the effect is still maintained 13 . By the way, sport or at least moderate exercise during fasting is important anyway, because it keeps the muscles contained and the body breaks down fat instead 2 . Strength training of a maximum of one hour and walks are the most sensible.
The facts about intermittent fasting summarized
Possible benefits of intermittent fasting:
✔ Detoxification processes in the body are promoted
✔ Chronic inflammation is eliminated
✔ Losing weight is supported (body fat reduction)
✔ Intestinal health is optimized: recovery and regeneration of cells and digestive enzymes
✔ Hormone balance: blood sugar, stress hormones and the body's own hormone production
✔ More concentration & performance
✔ Time saving
✔ Acid and alkaline balance is relieved and thus balanced
Possible disadvantages & challenges with intermittent fasting:
✘ Additional stress factor
✘ Cravings (sometimes only in the initial phase)
✘ Fatigue
✘ Challenge in everyday life (less spontaneity in social life)
✘ If the timing is wrong, muscles can break down
Conclusion on intermittent fasting
Intermittent fasting is not just a trend, but a process that has existed since time immemorial and has many positive effects on our health and general well-being. Combined with a healthy diet and enough exercise, fasting is an additional option for maximum health and performance in everyday life.
1 Roth, Daniel (2018): Healthy and slim through short-term fasting. Riva Publishing.
2 Martin, Hans Helmut (2014): Full energy while fasting. UGB forum special. S 10-14.
3 Enck, Paul and Frieling, Thomas (2017): Gut on the brain. Freiburg: Herder Verlag.
4 Kreutzkamp, Dr. Barbara (2020): Intermittent fasting – there is a lot to be said for it. In: Medical Tribune.
[https://www.medical-tribune.de/medizin-und-forschung/artikel/intermitteendes-fasten-vieles-spracht-dafuer; June 12, 2020].
5 Patrick, Dr. Rhonda (2019): Late-night eating and melatonin may impair insulin response. [https://www.foundmyfitness.com/episodes/melatonin-insulin-response; June 12, 2020].
6 Organic Workout (2019): Intermittent fasting – the solution to all problems or just hype?
[https://organic-workout.de/blog/interval-fasten-die-loesung-fuer-alle-problems-oder-doch-nur-hype; June 12, 2020].
7 Dietze, G.; Wicklmayr M. and Mehnert: Physiology of hunger metabolism.
8th Leitzmann, Claus (2018): Nutrition and fasting as therapy, edited by Rainer Stange.
9 Doccheck: Programmed Cell Death [https://flexikon.doccheck.com/de/Programmierte_Zelltod?utm_source=www.doccheck.flexikon&utm_medium=web&utm_campaign=DC%2BSearch; June 12, 2020].
10 Fasting IM and autophagy [https://www.klosterpernegg.at/methods/autophagie-interval-fasten; 05/30/20].
11 Brought, Dr. Med. Petra (2018): Intermittent fasting - For a long life - slim and healthy.
12 Hatori, Megum et. Al (2012): Time-Restricted Feeding without Reducing Caloric Intake Prevents Metabolic Diseases in Mice Fed a High-Fat Diet.
13 Patrick, Dr. Rhonda (2019): Fasting Q&A with Dr. Rhonda Patrick and Mike Maser.
[https://www.foundmyfitness.com/episodes/zero-fasting-qa; June 13, 2020]
