Intermittent Fasting: How Interval Fasting Works

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

What is Intermittent Fasting?

Intermittent means “interrupting”. Means: You interrupt your meal rhythm and abstain from food for some time. The fasting phases last from several hours up to one or two days. It is recommended to fast for at least 16 hours, then everything is guaranteed to be digested and the energy stores are empty. By intermittent fasting (also: interval fasting) one should be able to lose weight in a healthy way. The concept is, unlike e.g. therapeutic fasting, designed for long-term use.

The period from evening until the next noon is favourable 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 the subsequent intake of food.

Interval Fasting: No Problem for Our Body

Already in the Stone Age the body was prepared for periods of fasting – because food was not available at all times. Accordingly, food was eaten whenever possible in order to build up reserves for possible subsequent periods of hunger. The body could then draw energy from these reserves during this time. This mechanism has been protected until today, which is why interval fasting is not a problem for the body.

Why can You Lose Weight through Interval Fasting?

To produce energy, the body always converts carbohydrates into energy first, because the conversion of fats is more complex. Only when the carbohydrate stores are empty after about twelve hours is the fat burning process set in motion. If you fast for 16 hours a day, the fat is already being utilized and you lose weight.

The Variants for Fasting

There are different forms of interval fasting. In Germany, the 16:8 method is particularly popular, but everyone can decide individually which variant fits best into their own life. In general: During the fasting period only water, tea and coffee are allowed (black at best). The following forms of interval fasting exist:

16:8

Perfect for beginners and those who want to integrate fasting into everyday life: The fasting period here is 16 hours, 8 are eaten. Those who like to eat in the evening simply skip breakfast and eat normally until the evening over a period of eight hours. On the other hand, those who cannot get going without breakfast simply take it a little later than usual in the early morning. Thus, one could have breakfast at 11 a.m. and should then have eaten the last meal until 7 p.m. The concept is very flexible, as the meal times can be easily changed individually.

36:12

With this principle you eat normally for one day. Overnight and the next day there is no food and the fasting is broken again with breakfast the day after next. A certain amount of discipline is obligatory for this variant – only those who have no problem giving up food completely can keep it up for a long time.

20:4

They only eat four hours a day. Only recommended for a short time and not for beginners, as the concept is similar to the 36:12 method but difficult to maintain.

5:2

Five days a week, the 5:2 diet allows you to eat as much as you want, calories are not counted. The remaining two days of the week are fasting. Perfect for those who want to slowly lose a little weight and/or ease the digestion a little. The flexible principle is suitable for anyone who can manage to do without food completely.

Can I Eat what I want Outside of Lent?

Basically, you can eat what you want during the time when you are not fasting. However, the weight loss will naturally be higher if you avoid fatty, high-calorie meals and opt instead for a healthy diet, which should consist mainly of healthy carbohydrates (e.g. in wholemeal products), plenty of fish and lean meat as well as fruit and vegetables. In general, it is important to make sure you get enough fibre, vitamins and minerals and tend to consume more protein than carbohydrates. This also curbs your appetite and prevents ravenous appetite.

What Other Advantages Does Intermittent Fasting Have?

Studies on animals suggest that interval fasting not only helps you lose weight, but can also have other health-promoting effects. To it belong:

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

So far there are only a few studies on interval fasting carried out with humans, the results of which are not clear either. However, the authors of a review paper from the year 2015 come to the conclusion that the available data with human test persons provide evidence for the positive health effects of interval fasting.

Is Anyone Allowed to Do Interval Fasting?

Interval 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