I have tested Intermittent Fasting for 14 days – it works differently than many think
What you are reading right now, I write with a completely empty stomach. It’s almost 11 o’clock in the morning and I haven’t eaten any calories yet. Not a smoothie, not a bite of my beloved breakfast, not even a shot of oat milk in my coffee. And that will not change in the coming hour. Just two weeks ago, at the start of my fasting experiment, the prospect of eating absolutely nothing until 12 p.m. every day was a horror. For I love my breakfast. And I hate black coffee.
It took about two weeks before I was no longer a hungry, bad-tempered, black-coffee-sipping creep with a disgusted look on my face in the morning. It also took Frank Madeo two weeks to adjust to his new eating rhythm. Unfortunately, I didn’t ask the biochemist what his mood was when he started short term fasting. But why does he starve himself – and why should I starve myself?.
Animals that fast intermittently live longer, are fitter and healthier
"I wanted to test the results of our research myself," says Madeo. "I can give badly with my lectures pieces of advice, which I do not follow."Madeo is a professor at the Institute of Molecular Biosciences in Graz, a nutrition researcher and one of the most cited researchers on aging. On his Facebook page, he provides regular updates on science-based strategies for nutrition and health. So too about the increasingly popular intermittent fasting, also called interval fasting.
"When you observe in your own laboratory how positively periodic fasting affects a wide variety of organisms – from flies to mice to humans – you eventually try it yourself," says Madeo. For years, various studies on model organisms have proven that interval fasting is healthy. Animals that fast intermittently live longer and are fitter and healthier as they age.
Eight hours eating, 16 hours fasting
Intermittent fasting is also said to have an effect on body weight. "You can eat the same amount of food and still lose weight," Madeo tells me during our conversation before I start fasting. "You can probably also eat a little more and still lose weight."Contrary to popular belief, ultimately only the calorie balance of the day decides whether you gain or lose weight, Madeo says: "Numerous animal studies show that whether or not you get fat depends much more on timing than calorie count."
This is confirmed, for example, by a study from California. The researchers had fed mice a high-fat diet around the clock. The animals quickly became fat, developed a fatty liver, diabetes and vascular inflammation. A second group of mice were given the same amount of calories, but were only allowed to eat for a period of eight hours each day. They had to fast for the remaining 16 hours. These animals stayed slim and much healthier.
On myself, I could not notice any weight loss after two weeks. The good thing is that losing weight wasn’t what I was after. Although intermittent fasting is currently being hyped as the new diet miracle, in my opinion it offers significantly more benefits than just weight loss. Health benefits that are more relevant, at least for me, than whether I weigh a kilo less after two weeks of fasting. However, I also usually eat rather healthy, pay a lot of attention to what and how much I eat, and am of normal weight. For the past two weeks, I have been consciously changing my habits as a test: I didn’t look at calories, didn’t care about carbs or fat. In the eight hours I was allowed to eat – from noon to 8 p.m. – I just ate whatever I felt like eating. I haven’t lost any weight, but I haven’t gained a single gram either. At least not so far.
Controlled fasting boosts the cells’ self-cleansing process
Intermittent fasting comes in different variations. The principle however is always based on the fact that food is permitted only in a certain time window. The 8:16 method is especially popular, and I chose it because I thought it was the best way to go. Eating for eight hours, then fasting for 16 hours. Like the mice in the study.
Skipping dinner clearly seemed even less feasible to me than having to give up breakfast. After two weeks it became clear that I had made the right choice for me – in the meantime I rarely crave my porridge with fruit in the morning, but I really look forward to my dinner after work. If you also want to try intermittent fasting, you should choose the variation that you can best sustain. Because to change the method over and over again is not recommended, that messes up the body properly. Exactly how large the fasting window must be in order to achieve the ideal effect has not yet been clarified. "But to be safe, it should be at least 15 hours, preferably 16," Madeo says.
The fasting researcher believes that after 14 to 16 hours without food, the human body initiates a process called autophagy. The Greek word "autophagos" loosely translates to "consuming itself," which sounds a little disturbing, but describes the process quite accurately. "Autophagy is an elementary function," says Madeo. It keeps cells young longer. By fasting, we stimulate a kind of cell recycling in the body. "When the energy supply from outside ceases, cells start to clean up their own junk," says the researcher. "So does protein accumulation or broken cellular components that would otherwise accumulate as we age – molecular garbage that can lead to cancer or neurodegenerative diseases, for example."
Spermidine can specifically trigger the cleanup process
If we deprive the body of energy by fasting, our cells enter a state of emergency. The cell then decides to break down the parts it no longer urgently needs. In this degradation process, the cell produces energy again. Autophagy can be specifically triggered through controlled fasting, Madeo says.
Japanese scientist Joshinori Ohsumi won the Nobel Prize in 2016 for his research on autophagy. "In the beginning, it was just very abstract basic research," Madeo says. "Now we know that aiming to trigger autophagy once a day is very likely to be good for the human body."When the biochemist and his team investigated the mechanism, they came across a substance called spermidine. This could also trigger the cleaning up of the cells – without the need to abstain from food.
Spermidine is a naturally occurring substance in the body whose concentration decreases with age, but which can also be ingested with food. Administration of a supplement rich in spermidine has already been successfully tested against dementia at the Charite hospital in Berlin.
Fasting – without fasting
Madeo and his team found that consistent dietary intake of spermidine-rich foods protects against age-associated diseases. Thus one can let the body fast, although one takes up food. "Spermidine is found in soybeans, aged cheese, pears, peas, wheat germ, mushrooms and coffee, among other things," says the researcher.
Coffee. Even after completing my two weeks of fasting, I drink it before 12 p.m. without calories, which means no milk or sugar. In the meantime I got used to it. Only the first sip sometimes still shakes me a bit. In addition Madeo was correct, the body accustoms itself actually quite fast to the new rhythm – in the meantime I hold out it well until noon, before I eat something for the first time.
According to the researcher, if by then my stomach is growling, that’s a positive sign. "Feeling hungry once a day is a good thing, in the spirit of autophagy," says Madeo. "Welcome hunger like a friend and your body will be cleaned up!"
Whether I have kept up the two weeks interval fasting? Yes. Whether I will keep it up in the future? I do not know yet. But I will definitely try. Intermittent fasting is not a diet, Madeo says. It doesn’t feel like one either, I must admit. "This is the normal way of eating, to eat rather infrequently, but then eat a lot – this is how humans have eaten for 99.9 percent of evolutionary history."There are also indications that one is particularly concentrated after a longer fasting period. "Evolutionary psychology," says Madeo. "The hunter in us then says: watch out, you loser, you haven’t shot any game for two days, now you’d better concentrate, otherwise you’ll soon be out of the window!" Sounds somehow plausible.
I, Loser, now greet my hunger, which in the meantime is slowly setting in, with a concentrated walk to the coffee machine.