Intermittent fasting: this is how intermittent fasting works


Intermittent fasting is just right for anyone who wants to lose weight without a strict diet. We explain how intermittent fasting works exactly.

What is Intermittent Fasting?

Intermittent means "interrupting". That means: You interrupt your meal rhythm and forego food for some time. The fasting phases last from several hours to a day or two. At least 16 hours are recommended, then everything is guaranteed to be digested and the energy stores are empty. Intermittent fasting (also: interval fasting) should allow you to lose weight healthily. The concept is different from z. B. Therapeutic fasting is designed for long-term use.

The period from evening until the next noon is favorable for fasting because then the seven to eight hours of sleep are integrated, during which one does not eat anyway. There are then no restrictions whatsoever on subsequent food intake.

Intermittent fasting: no problem for our body

As early as the Stone Age, the body was prepared for phases of fasting - because the food was not available at all times. Accordingly, they feasted whenever possible to build up reserves for possible subsequent periods of starvation. The body could then draw energy from these reserves during this time. This mechanism has been preserved to this day, which is why intermittent fasting is not a problem for the body. 

Why can you lose weight through intermittent fasting?

To generate energy, the body always converts carbohydrates into energy first, because the conversion of fats is more complex. Fat burning is only started when the carbohydrate stores are empty after about twelve hours. If you fast 16 hours a day, the fat is already being used and you lose weight.  

The variants in fasting

There are different types of intermittent fasting. In Germany 8 method popular, but everyone can individually decide which version fits into one's life best: especially the 16's. As a general rule, during Lent only water, tea and coffee are allowed (black at best). There are the following forms of intermittent fasting:

16: 8

Perfect for beginners and those who want to integrate fasting into everyday life: the fasting phase here is 16 hours, 8 are eaten. If you like to eat in the evening, you can skip breakfast and eat normally for eight hours until the evening. If, on the other hand, you can't get going without breakfast, you can simply eat it a little later than usual in the early morning. So you could have breakfast at 11 a.m. and then have your last meal by 7 p.m. The concept is very flexible, as the meal times can easily be moved individually.


With this principle, you eat normally for a day. There is no food overnight and the next day, and the fast is broken again with breakfast on the day after next. A certain discipline is compulsory for this variant - only those who have no problem doing without food can hold out for a long time.

20: 4

Here you only eat four hours a day. Recommended only for a short time and not for beginners, as the concept, like the 36:12 method, is difficult to maintain.

5: 2

With the 5: 2 diet, you can eat as you please five days a week, calories are not counted. The remaining two days of the week fast. Perfect for those who slowly lose weight and/or want to take some pressure off the digestion. The flexible principle is suitable for anyone who can manage to forego food entirely. 

Can I eat what I want outside of Lent?

Basically, you can eat what you want during the time you are not fasting. However, the decrease will of course be higher if you tend to avoid fatty meals with a lot of calories and instead rely on healthy foods that consist primarily of healthy carbohydrates (e.g. in whole grain products), lots of fish and lean meat, as well as fruit and vegetables should. In general, it is important to ensure that you have enough fiber, vitamins, and minerals and that you tend to consume more protein than carbohydrates. This also curbs the appetite and prevents cravings.

The best recipes

Tip: We'll tell you the best intermittent fasting recipes here!

What other advantages does intermittent fasting have?

Studies in animals suggest that intermittent fasting not only helps you lose weight but can also have other health-promoting effects. These include:

  • The risk of chronic diseases such as diabetes, cancer, and cardiovascular disease decreases
  • Life expectancy can increase thanks to the delay in so-called neoplastic disorders (uncontrolled growth of certain cells or tissues)

There are so far only a few human intermittent fasting studies, the results of which are inconclusive. However, the authors of a review from 2015 come to the conclusion that the available data with human test subjects provide indications of the positive health effects of intermittent fasting.

Can everyone do intermittent fasting?

Intermittent fasting is not suitable for everyone. The following groups of people should only fast in consultation with a doctor:

  • children
  • Competitive athlete
  • Pregnant women 
  • Chronically ill people