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What is Intermittent Fasting (IF)?

What is intermittent fasting?

Lately, I have been repeatedly asked about “intermittent fasting” or “intermittent fasting” and what I think about it. What is intermittent fasting and why should this work, if you want to lose weight? Is it also suitable for those of us who do sports? What should you consider while exercising? I’ll tell you because I try to follow this diet as well as possible! Here’s some scientific evidence combined with my personal experience.

“Intermittere” comes from Latin and means “interrupt”. So, you are fasting with a few dropouts to eat. Accordingly, it is a combination of the known act of fasting (complete abstinence of food), with phases in which you eat normally. There are mainly two common variants: the 16:8-method and the 18:6-method. For example, 16 and 18 means that you are keeping your lent for 16 or 18 hours. So, you have 8 or 6 hours to eat. This means you have your meals e.g. between 10 o’clock in the morning and 16 or 18 o’clock in the evening. After 4 or 6 PM you don’t eat anything until the following day at 10 AM. Only water and unsweetened tea or coffee are allowed.

Advantages of intermittent fasting

I’ve already told you the benefits of fasting in this blogpost. Most people practice it to lose weight – see here, how to maintain weight loss after diet. Advantages of intermittent fasting are above all the avoidance of a yo-yo effect, fewer cravings, and fewer feelings of weakness than with other diets. In addition, it is much easier to integrate into everyday life and socially easier to follow than a complete fast with asceticism. The basic idea of intermittent fasting is the alternation between a food and a digestive phase. Plus, it is not defined what you should eat. Of course, it makes sense to follow a healthy diet. So, avoid refined sugar, preferably don’t eat fast food, just little processed products, etc.

Furthermore, it is also advantageous that many people prefer to have breakfast and don’t need to eat that much in the evening or vice versa. Since the interval can be pushed forwards or backwards, if you wake up early and like to have breakfast, you can take your first meal at 7 AM. If you follow the 16:8-rhythm, then you shouldn’t eat after 3 PM. If it’s easier for you to just have a cup of coffee in the morning and have your first meal at lunchtime, according to the 16:8-rule, your first meal should be around noon and your last meal should before 8 PM.

Above all, my personal advantage of intermittent fasting is that I avoid snacks in the evening. Let’s face it, in the evening on the couch you do not eat anything which you could call “healthy” anyway. 😉

Intermittent Fasting is everything about the right timing
Intermittent Fasting is everything about the right timing

What other forms are there?

In addition to the 16:8- or 18:6-rhythm, there is also the 36:12- or the 20:4-rhythm. They work just like the two already mentioned. Either, you will be fasting for 36 hours and eat your calories within 12 hours or you will be fasting for 20 hours and eating within 4 hours. Also possible are whole days of fasting, either to compensate for small sins (Hello Christmas!) or generally, to give your gastrointestinal tract time for spring-cleaning.

Why does intermittent fasting work?

Studies confirm that intermittent fasting works. On average, we eat less during mealtimes compared to having the opportunity to eat throughout the day. In addition, fat-burning is not active until our sugar stores are completely empty and insulin levels are down. That’s when our body is able to effectively burn fat and our body turns into ketosis (I’ll tell you more about ketosis soon!).

The longer we do not feed our body with carbohydrates (sugar), the better and longer our fat-burning will work. It works a bit like a light switch: Either the light is on or off. Both do not work at the same time. So, the insulin level is either high and the fat burning is down. Or the insulin levels are low and the fat-burning is at full speed.

Even athletes do it!

Among athletes, especially the 16:8-method is very popular. I practice this myself if I am not trying to follow my OMAD (one meal a day) principle or the external circumstances make it too complicated. Also soon more! 🙂
Sport can boost fat-burning during intermittent fasting. You can imagine that your insulin stores are empty in the morning after e.g. 14 hours of fasting. If you are exercising, you catapult your fat burning to the top. Of course, you focus here on losing weight, especially fat.

The more you try interval fasting, the better your body will be able to use glycogen (stored sugar) more effectively. Here it would be useful to go exercising 3-4 hours after your last meal. So, you already use a large part of your carbohydrate storage and the fat-burning can start earlier at night. Sport and intermittent fasting are a great combination! The body fat melts and the muscle mass remains largely constant. By the way, you also get to grips with the persistent fatty tissue! More weight loss tips here.

Positive effects of intermittent fasting

Not only losing weight is in the focus of intermittent fasting, although it is the main motivation of most. Studies show that the overall health status of fasting people is also measurably improving. Both, the risk of diabetes and the risk of heart disease can be demonstrably reduced! Studies showed that subjects who had intermittent fasting had a measurably more constant blood sugar level and thus had fewer cravings. That’s why the yo-yo effect is almost non-existent within intermittent fasting. In addition, you improve your general awareness of your body and learn to feel “true hunger”. Many of us do not know the difference between hunger and habitual eating, because they are constantly eating and the body does not really get hungry.

In addition, studies show that inflammation in the body is generally better controlled. Thus, the interval fasting has an antioxidant effect! Christian Zauner and his colleagues showed in a study that intermittent fasting increases the basal metabolic rate and makes our body more efficient overall! Both the repair mechanisms of your DNA and the metabolism of dead cells works much better and more efficiently. There are positive effects recorded on nervous diseases as well as Alzheimer’s and Parkinson’s as well as cardiovascular disorders.

Time for restoring

If our body has less to do with constantly digesting something and pumping the blood into the gastrointestinal tract, it can focus more on the really important body mechanisms. If we are less concerned with digestion and, therefore, lethargic, the immune system and general repair mechanisms can be better cared for. That’s why many people fast when they are ill. So, your bodily functions can focus on your immune system best.

Disadvantages of interval fasting

There are actually no disadvantages of interval fasting, except that you could find it difficult to change your diet and don’t eat for more than 4 hours daytime. Some people also complain of increased irritability, tremor, headache or weakness. All this is summarized under the term “hypoglycemia” and describes above all the varying of your blood sugar level. Since we are accustomed to eating something anytime and anywhere, have sweetened beverages to drink, our blood sugar level is constantly in turmoil. If it has experienced this diet for 30 years of your life, it is not surprising that it first has to adapt to not being permanently fed.

Similar symptoms also occur with a low-carb diet and are typical withdrawal symptoms that can also be caused by drugs. It sounds strange but it the truth! As with any type of diet, risk groups such as pregnant women, breastfeeding women, and those already suffering from an illness should turn to a nutritionist.

The healthier you eat, the healthier your weightloss will be
The healthier you eat, the healthier your weight loss will be

My personal experience with intermittent fasting

I discovered intermittent fasting a long time ago. At the same time, I did not know that there was even a description of my diet at that time! 🙂

For a long time, I was an absolute breakfast-lover and still enjoy my porridge today. And I really do not like eating late at night, because then I hardly fall asleep and toss and turn in bed. When I’ve lost 30 kilograms, I also tried to stop eating after 6 PM. At that time, I usually had breakfast around 10 o’clock at the “big break” in school. So I fasted on the 16:8-principle. In addition, I’m an absolute night-owl and the evening is my best time. I also go to sports in the evening and, so, have followed the rules of intermittent fasting without me even knowing it! 🙂

My way to weight-loss

Looking back, I can say that it helped me lose weight healthily. Besides, at that time I never had the feeling that I had changed something great. Of course, I paid attention to a healthy diet and more sports. But it was really no self-looting and super integrated into everyday life. And so it is today!

I really do not count each hour properly and stop the time when exactly I am eating or not. But by and large, my eating-rhythm is anyway within six hours most of the time. And the body gets used to this diet very quickly. We must not forget that we are one of the first generations to always eat anything or to drink something sweet. All our ancestors did not have that. It is more natural for us to fast. And if there is something to eat, we should take the chance and above all chew properly.

Previously, our ancestors did not know when the saber tooth tiger would be ready for Sunday brunch. Maybe next time in 4 months, maybe never again? Or the next saber tooth tiger would rather have our ancestors for brunch? Nowadays, the permanent activity of our digestive system is one of the main triggers for food intolerances and allergies. I have briefly mentioned this in my blogpost to fasting in general, but soon more.

Tips and tricks for interval fasting

1. Test your own rhythm!

In any case, you should first think about what your favorite and main mealtime is. Then, tinker with everything else. Start by increasing the time between your dinner and your breakfast. Afterward, you can start with the 16:8-method. And if you do that easily, you can still switch to the 18:6-method. But do not stress yourself. Stress is completely counterproductive.

2. Try to eat as many unprocessed foods as possible!

I mean sugar, white rice, white bread, sweetened drinks, fast food, sweets, etc. I think you know what I’m after. The more unprocessed food you eat, the more fiber you eat, and the longer you’re saturated. Personally, I eat vegan and eat as much raw food as possible. In particular, pulses such as chickpeas, fresh fruits and vegetables, nuts, and wholegrain cereals touch down on my plate and in my stomach. This keeps me very saturated for a long time and thus I can eat on some days only once a day. The portion is therefore huge, but then I have no problem at all to fast for the next 24 hours.

3. Drink enough water and unsweetened tea or coffee!

This is precisely the factor that makes many think that they are fasting intermittently, but they do not. The mistake is milk or sugar in coffee or tea. Much worse is alcohol in the evening. Even small amounts of sugar can break your fasting. Everyone reacts differently. One metabolism is completely paralyzed, the other is not. There is not really a rule of thumb. In my research, I often came across the value “35 kcal”. That’s about a shot of milk in the coffee. But that also varies greatly from person to person. Conclusion: If possible, no calories while fasting!

4. Fast at least for 14 hours!

Only then, the first positive effects of intermittent fasting become apparent. For example, the cleaning processes of the gastrointestinal tract can only begin when it is empty. Incidentally, this is also the reason why there are allergies and food intolerances. In our diet today, our stomach is never empty and before it gets that far, the next apple juice marches in. A little bit like cleaning at home: The less you get to it, the worse it gets!


Both, the current case studies and my personal experience say: With intermittent fasting, you can lose weight healthily. In addition, your body benefits in so many different areas. And one thing you should not underestimate: Even your self-discipline is put on the test and practiced. It sounds like a “positive vicious-circle”! And I guarantee that you can stand it, not to eat anything for 18 hours. Yes, I would even gamble my butt away for it – and my butt is really sacred to me because it brings the money home. 😉

Do you still have questions? Then always with it! 🙂
So, let’s go, I’m looking forward to your experience – keep me updated!
To stay up to date here is my Facebook Fan page. 🙂 Sharing is caring!

Here are all scientific studies and science-based evidence for this blog post

Antoni, R./Johnston, K. L./Collins, A. L./Robertson, M. D. 2014: The Effects of Intermittent Energy Restriction on Indices of Cardiometabolic Health, in: Research in Endocrinology, Vol. 2014.

Cignarella, F./Cantoni, C./Ghezzi, L./Salter, A./Dorsett, Y./Chen, L./Phillips, D./Weinstock, G. M./Fontana, L./Cross, A. H./Zhou, Y./Piccio, L. 2018: Intermittent Fasting Confers Protection in CNS Autoimmunity by Altering the Gut Microbiota, in: Cell Metabolism, Vol. 27, 2018, No. 6, pp. 1222-1235.

Johnston, J. B./Summer, W./Cutler, R. G./Martin, B./Hyun, D. H./Dixit, V. D./Pearson, M./Nassar, M./Telljohann, R./Maudsley, S./Carlson, O./John, S./Laub, D. R./Mattson, M. P. 2007: Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma, in: Free Radical and Biology & Medicine, Vol. 42, 2007, No. 5, pp. 665-674.

Mattson, M. P./Longo, V. D./Harvie, M. 2017: Impact of Intermittent Fasting on Health and Disease Processes, in: Ageing Research Reviews, Vol. 39, 2017, pp. 46-58.

Mihaylova, M. M./Cheng, C.-W./Cao, A. Q. et al. 2018: Fasting Activates Fatty Acid Oxidation to Enhance Intestinal Stem Cell Function during Homeostasis and Aging, in: Cell Stem Cell, Vol. 22, 2018, No. 5, pp. 769-778.

Santos, H. O./Macedo, R. C. O. 2018: Impact of intermittent fasting on the lipid profile: Assessment associated with diet and weight loss, in: Clinical Nutrition ESPEN, Vol. 24, 2018, pp. 14-21.

Varady, K. A./Bhutani, S./Church, E. C./Klempel, M. C. 2009: Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults, in: The American Journal of Clinical Nutrition, Vol. 90, 2009, No. 5, pp. 1138-1143.

Zauner, C./Schneeweiss, B./Kranz, A./Madl, C./Ratheiser, K./Kramer, L./Roth, E./Schneider, B./Lenz, K. 2000: Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine, in: The American Journal of Clinical Nutrition, Vol. 71, 2000, No. 6, pp. 1511-1515.

What is intermittent fasting? Can I lose weight with an IF diet healthily? Here is some scientific evidence combined with my own experience as a nutritionist!

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