Intervall fasting: Losing weight without starving?


Weight loss without starving and at the same time being vital and efficient - many people who want to lose weight hope for interval fasting. The fanbase of so-called intermittent fasting is getting bigger and bigger. Unlike traditional fasting, food is not left out for days or even weeks. The fasting phases are manageable and alternate with phases of the normal diet - so this rhythm can be very well integrated into everyday life. In addition to weight loss should also improve the periodic fasting and the sugar and fat metabolism. How interval fasting works, what it does and how healthy this form of diet is, is explained below.

What is interval fasting?

Characteristic of the interval fasting, which also as intermittent fasting is the change of phases of eating and phases in which nothing is eaten - so you fast at intervals.

There are different forms of Intervallfastens: It can be fasted by the hour, but also a full day. Interval fasting requires no complicated instructions and no special diet plan - the intervals between eating and fasting are crucial.

Which methods of interval fattening are there?

Depending on how long the intervals last, a distinction is made between different methods of interval fattening. The most famous forms are:

  • the 16: 8 method
  • the 5: 2 method
  • the 1: 1 method
  • the 12:12 method

In addition, different spellings are common, for example, "16/8 method" or "5 to 2 method". All terms describe the ratio of the duration of eating to fasting intervals.

What does 16: 8 interval fasting mean?

16: 8 interval fasting is the most popular form of interval fattening. Here one limits the time, in which one may eat, to eight hours. The remaining 16 hours of the day is fasted - one speaks in this context of the 8-hour diet.

A daily schedule with this method could therefore look like that you take food daily only between 11 clock and 19 clock. In the time until 11 o'clock the following morning only calorie-free drinks are allowed. Alternatively, you can set the meal phase from 8 am to 4 pm and do without the dinner.

One of the special advantages of the Intervallfastens: Such a plan can be adapt flexibly. If, for example, a dinner is in good company, you can extend the fasting phase to the point where the 8-hour time window for the meal is pushed back in time.

Intervall fast in 5: 2 ratio

In the 5: 2 variant is on five days a week normal, so eaten without food breaks and restrictions. On the two remaining days, the calorie intake in women is limited to about 500 kcal (kilocalories), in men to 600 kcal.

Ideally, these days you will be dispensing with easily digestible carbohydrates, such as those found in pasta, wheat flour, or sugar, and will be consuming low-sugar fruits, vegetables, and lean sources of protein.

For the two days of fasting, ideally, you should choose non-consecutive days that are not as stressful.

1: 1 method and 12:12 method - fasting and eating in common mode

"Eat Stop Eat" or Alternating Fasting describes the 1: 1 method of interval fattening. This form alternates between one day and normal eating the next day.

In the 12: 12 Method the intervals are only 12 hours each - a relatively short form of "part-time fattening". For example, you can set the time window for eating between 7 am and 7 pm - for many a normal daily schedule anyway. However, this is not a common variant of the Intervallfastens due to the relatively short meal break.

Intervall fast for beginners

For beginners, the 16: 8 shape of the Intervallfastens is particularly well, because the night's sleep is one of the meal break. If you like: Losing weight while sleeping, which incidentally often also contributes to an improvement in sleep quality.

By the way: The 16: 8 Intervall fast has in particular by the television doctor Dr. med. Eckart von Hirschhausen attained great fame, which could thus achieve considerable success and lose ten kilograms - this form of fasting is therefore occasionally also called Hirschhausen Diet designated.

What can one eat at interval fasting?

Intervall fasting is based on a healthy diet, without, however, setting specific requirements or imposing restrictions. So one should during the eating phases so neither excessively eat nor meticulously count calories. As is often the case with intermittent fasting, a healthy and balanced mix is ​​the key to success.

In the almost phases should only be drunk, if possible calorie-free - the most suitable are:

  • Water (if necessary with a dash of apple cider vinegar or a slice of lemon)
  • thin vegetable stock
  • heavily diluted juice spritzers
  • unsweetened tea

Also coffee is allowed, but without sugar and sweeteners. Those who drink their coffee with milk can continue to do so. Although milk has some calories - a small sip will not spoil the success of the interval fattening.

In longer periods of fasting, a home-cooked vegetable or chicken broth can help nourish the body and reduce the feeling of hunger.

Is alcohol permitted during interval fasting?

Just as one is allowed to eat normally in the eating phases, alcohol is also allowed during interval fasting. However, this, of course, only in moderation.

However, alcohol is taboo during the fasting intervals.

How does interval fasting work?

In contrast to other diets, the principle of the Intervallfastens is not based on the reduction of calories, but aims to move the body through the long meal breaks to adapt the metabolism.

The theory behind it: If a meal break lasts more than 14 hours, the body switches on from the carbohydrate combustion fat burning This is done by using the fats stored in the body.

In contrast to a crash diet, in which the metabolism switches to "economy mode", the interval fasting should not cause a JoJo effect. For this reason, interval fasting is often used as a diet for weight loss.

Losing weight with Intervall fast?

Scientific studies on mice1 have shown that feeding according to the principle of interval fattening can improve weight problems. It is not necessary to reduce the amount of calories to cause weight loss.

A pilot study with human subjects also seems to prove this.2 In addition, another study showed that less fat is lost in interval fasting than in a diet with calorie reduction.3

Further effect on health

But other health-promoting aspects could be observed in the above-mentioned mouse study. Thus the blood values ​​of the mice were improved and thus the danger of the Diseases of the heart and circulation reduced. An anti-inflammatory effect and an improvement in the LDL cholesterol levels have also been shown several times.

If the food intake is distributed throughout the day, the body spills out insulin again and again. However, insulin prevents fat burning for several hours. The body cells develop over time an immunity to the insulin and thus a precursor of Diabetes. Interval fasting may possibly counteract such a disturbance. This is indicated by studies in which an improvement in insulin sensitivity could already be established.4

Another positive consequence of intermittent fasting is an increased secretion of growth hormone Somatropin. This hormone affects fat metabolism and protein synthesis. This results in an increased muscle buildup.

Cell cleaning by interval fasting

Also, the effect of cell recycling - the so-called autophagy - is often called in connection with interval fasting. In the fasting phase, the individual cell gains its energy from components that are not vital, for example, from old and defective cell parts - this is how the cell itself cleans itself.

However, overeating will disrupt this process. By fasting, however, the body is no longer concerned with digestion and can turn to cell cleaning. Animal experiments even suggest that this effect could prolong life.5,6

7 tips: This is how the interval fasting succeeds

For a successful interval fasting you should follow the following tips:

  1. Start slowly: To get started, it may be advisable to start with a fasting interval of 12 hours first and then slowly extend the fasting period to 16 hours.
  2. Do not put too much weight on yourself: Avoid especially physical stress during the fasting intervals.
  3. Eat well and healthy, with plenty of vegetables and protein and not too many carbohydrates.
  4. Avoid snacks between meals as well as excessive gluttony - just eat regular servings.
  5. Be sure to drink a lot throughout the day. It's best to start the day with a glass of water.
  6. Exercising on an empty stomach can help boost digestion. It can already be 10 minutes walking or jumping rope sufficient.
  7. Coffee or drinks with taste help against hunger attacks, for example a glass of water with a slice of lemon.

How long should interval fasting last?

How much and how fast you can lose weight with interval fasting is quite different and of course depends on how you feed during the eating phase. There is no time limit for the fasting method. If the weight loss is in the foreground, you can slow down the interval fast and stop gradually when you have reached your weight goal.

However, it is also possible to use interval fasting as a long-term diet. It is sufficient to fast three days a week, for example, according to the 16: 8 method.

Side effects and disadvantages of Intervallfastens

Dizziness, headaches and freezing can be side effects, especially at the beginning of the interval tensing. These minor side effects, however, usually after a first time of getting used to.

A possible cause of dizziness may be salt deficiency. The remedy here can be to add a pinch of salt to a glass of water. You should also make sure to drink enough. Hot tea, a warm foot bath and an extra layer of clothes help against the cold.

For whom is Intervall fasting not suitable?

In principle, every healthy person can try interval fasting. For children, adolescents and nursing women and pregnant women, intermittent fasting - just like other diets - is considered unsuitable, as the risk of nutrient deficiency is too great. The same applies to older people as well as persons with severe underweight or eating disorders.

Take drugs You should consult your doctor before starting fasting if Interval Fast is suitable for you. Caution should be exercised, especially in people with diabetes, since fasting can lower blood sugar levels, which can be dangerous in combination with blood sugar lowering drugs.

at Pre-existing conditions Like cancer, metabolic disorders, low blood pressure or chronic illness it is also advisable to talk to a doctor first.

Criticism of interval fasting

Even though initial scientific studies attribute positive effects to interval fasting, there is also criticism. The DGE (German Nutrition Society) speaks Intervall fast no lasting benefit to: "The DGE does not consider this method to be meaningful in the long term to regulate the weight. A conversion to a health-promoting diet does not take place thereby."7

Also researchers from the German Cancer Research Center in Heidelberg certify the 5: 2 method no better results in terms of weight loss than a reduction in daily calorie intake.8

The number of human medical studies on the effectiveness of interval harvesting and its effects on health is still low, Long-term studies are completely missing. Often, the results contradict or the scientists draw different conclusions from their observations. In addition, the different studies work with different types of Intervallfastens, so the results are hardly comparable. It is therefore still too early to conclusively assess the benefits or possible side effects of interval fattening.9

Conclusion: interval fasting can be worthwhile

The effects observed in studies indicate that not only the what, but also the when can be crucial for a healthy and vital body. Although the effects of the fasting method have not yet been adequately studied, many researchers believe that interval fasting has the potential to counteract diseases - negative effects can not be derived from previous studies.

However, every part-time fasting person must be aware that not everything, and certainly not too much, should be consumed in the food phases. The amount eaten and the nutritional content of the food should always be kept in mind - a healthy food selection is therefore urgently advisable. It is not in the sense of interval fattening to eat more than is actually necessary to be able to survive the subsequent meal break better.

With a balanced diet, the interval fasting could help to increase your own well-being and lose additional troublesome pounds. Intermittent fasting is thus not just a diet, but a diet setting to keep your weight feeling good. In combination with healthy recipes and sports to compensate for everyday life Intervall fasting can be a good basis for long-term (weight loss) successes.

Sources and studies

  1. Joslin, P.M.N. et al. (2016): Obese mice on a high-fat alternate-day fasting regimen lose weight and improve glucose tolerance.
  2. Stote, K.S. et al. (2007): A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults.
  3. Varady, K.A. (2011): Intermittent versus daily calorie restriction: which regimes is more effective for weight loss?
  4. Harvie, M. et al. (2013): The effect of intermittent energy and carbohydrate restriction v. daily energy restriction on weight loss and metabolic disease risk markers in overweight women.
  5. Longo, V.D. & Mattson, M.P. (2014): Fasting: Molecular Mechanisms and Clinical Applications.
  6. Xie, K. et al. (2017): Every-other-day feeding extends lifespan but fails to delay many symptoms of aging in mice.
  7. German Society for Nutrition e. V. (2014): Flash diets remain without lasting success. Diet promises to bikini figure have high season. Press release.
  8. Schübel, R. et al. (2018): Effects of intermittent and continuous calorie restriction on body weight and metabolism over 50 wk: a randomized controlled trial.
  9. Backes, G. / German Society for Nutrition e. V. (2018): Fasting, Basenfasten, Intervall fast - an overview.




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