Here is a snack, there is a soft drink: Many people feed their body with calories almost constantly. This doesn’t have to be the case with interval fasting. But how do regular meal breaks affect health?
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16: 8, 14:10 or 5: 2? The formulas for interval fasting are complicated to read, and the principle of all methods is simple: you eat little or no food over a period of time. This is not a problem for most people, but not for everyone. Children and pregnant women, for example, shouldn’t do that.
According to the internist and nutritionist Prof. Andreas Michalsen, the most common forms of intermittent fasting are variants of time-restricted eating. These include the 16: 8 and 14:10 diets as well as the 5: 2-Fasten or the two-day diet. But what do the numbers mean?
16: 8 or 14:10: what the numbers mean
16: 8- or 14:10 diet: You don’t consume anything other than water, unsweetened tea or black coffee for a period of 16 or 14 hours. In the remaining eight or ten hours you can eat normally, explains Antje Gahl from the German Nutrition Society (DGE).
“There are not so many guidelines regarding the choice of food. The diet should be as balanced as possible and you should eat early in the evening and have breakfast late,” says Gahl.
5: 2 fasting or two-day diet
With these forms you eat normally five days a week, fasting on two days. With the two-day diet, the fasting days should follow one another – you should consume a maximum of 650 calories each, explains Gahl. With the 5: 2 principle, the fasting days do not have to be consecutive, but they should have a fixed rhythm – for example, always on Tuesday and Friday. A quarter of the usual energy intake is then allowed, which corresponds to approximately 500 to 650 calories.
Get used to two to four weeks
Andreas Michalsen advises those who want to start interval fasting to give their bodies two to four weeks to get used to. “At first you are hungry, that is normal. After getting used to it, you can judge whether it is good for you,” says the chief physician of the naturopathy department at the Immanuel Hospital Berlin, who looks after around 1,500 fasters there every year.
And then, that’s what most fasters hope for, the pounds will tumble. According to the doctor, this calculation works in most cases. A miracle cure in matters Lose weight But interval fasting is not, according to nutritionist Gahl. There are rather minor effects on the body mass index, which describes the ratio of weight to height and is a rough indicator of overweight and underweight.
Fasting has the advantage, according to Gahl, that the unhealthy belly fat is reduced. And: “With strict diets, the body breaks down fat-free mass, that is, muscles. This is reduced with interval fasting.”
Studies show positive effects
There are now several clinical studies on the effectiveness of this type of fasting in healthy adults, but most of the results came from animal studies, Gahl summarizes.
This shows many positive effects: in addition to weight loss, the metabolism improved, for example, in Diabetes Type 2, says Gahl. The risk of cardiovascular and neurological diseases decreased, the brain function improved, the Blood pressure, the blood lipid values as well as the fasting blood sugar also.
Criticism of the concepts
But there is criticism beyond the study situation: “Most concepts contain no or only vague recommendations for food selection,” says Antje Gahl. “If people do not know exactly how they can now eat better quality or feast uncontrollably, the health-promoting effects fizzle out, and unfavorable eating habits are not changed.”
Andreas Michalsen, on the other hand, thinks that people eat better because of the Cravings put. But he also emphasizes: “No matter what you eat, you only eat after the clock – it shouldn’t be like that, of course. The best thing to do is to combine healthy eating with fasting.”
Intermittent fasting also carries risks: blood pressure and Blood sugar can fall off and you can a headache get, explains Gahl. It is particularly important to drink at least 1.5 liters a day, preferably water. Pregnant women, nursing mothers, children and adolescents should not fast. This also applies to people with eating disorders. Anyone with previous illnesses should consult with their doctor.
But: “Basically, the body can handle meal breaks well,” says Gahl. Intermittent fasting is basically suitable for every healthy person and can be easily integrated into everyday life.
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