Hannover. Intermittent fasting is becoming increasingly popular – presumably also because, contrary to “classic fasting”, people can eat. At Lent this year (starting on January 26th), this form might be a compromise. Those who opt for an interval fasting cure can eat between six and eight hours a day, the remaining hours of the day are then fasted. The principle is usually 16: 8, i.e. eight hours of food, fasting for 16 hours at a time.
Also possible the 5: 2 method. Here you can eat normally five days a week and on two days the calorie intake is significantly reduced. 600 to 850 calories a day for men and 500 to 800 calories for women. The alternate day fasting principle is probably the most radical: a complete day is fasted and a day is eaten normally, always alternating. A diet that is promised a lot – rightly? It is proven: the pounds are disappearing, but long-term studies are missing.
Four weeks of intermittent fasting: these are the results
Researchers around Frank Madeo from the Institute for Molecular Biosciences in Graz published theirs in August last year Results in the trade magazine “Cell Metabolism”. The team examined about a hundred normal weight and healthy participants. Half of the participants fasted according to the alternate day fasting principle for six months. All subjects had meal breaks of 36 hours each because they had not consumed anything during the night between fasting and non-fasting days.
The other half of the subjects were able to continue eating as usual. The researchers then randomly selected 25 of them to hold the alternate day fasting program for four weeks. This enabled the researchers to examine the short-term and long-term effects of the change in diet. Incidentally, the test subjects could not cheat; sensors on their skin checked their sugar level. During the study, the scientists collected thousands of data from blood pressure to insulin values to bone density measurements.
After four weeks, a number of positive health effects could be identified:
- The amount of lipotoxic Android stock fat, commonly known as belly fat, decreased. Also the fat that surrounds organs (keyword: fatty liver) decreased among the subjects who fasted.
- On average, the participants in the four-week fast cure lost 3.5 kilograms.
- The cholesterol level decreased, reducing the risk of heart attacks and strokes.
- An increase in the ketone bodies, which were also detectable during the eating phases, and a reduction in the thyroid hormone triiodothyronine (T3) are an indication that interval fasting could have a beneficial effect on aging processes in the body.
- Previous studies showing that subjects are more susceptible to infection could not be proven in this study. There were no negative effects after half a year.
Further advantages – proven by studies
The latest study on fasting was published in mid-February 2020. The American neuroscientist Mark Mattson and his colleague Rafael de Cabo from John Hopkins University have the effects of interval fasting examined for health, signs of aging and diseases and published in the specialist magazine “New England Journal of Medicine”. According to the authors, the request to view the current study situation came from the specialist magazine itself. Accordingly, more and more patients are seeking advice from doctors about whether and how they should take intermittent fasting – but many doctors would have to fit because they were not familiar with the topic. So this study should also be a kind of guide.
The study on interval fasting, which relates to studies on animals and humans, let the researchers filter out some positive health benefits:
- A big advantage of interval fasting, or the limitation of 500 to 700 calories per day for several weeks, is the increased ketone content in the test subjects. The rise of this molecule improves blood sugar regulation and prevents the body from generating free radicals – atoms that can damage cells.
- By regulating blood sugar, the meal break helps to make the body more resistant to stress and inflammation.
- A study by the University of Toronto found that 220 healthy, non-obese adults who had been on a reduced-calorie diet for two years showed signs of memory improvement in a series of cognitive tests.
- According to the authors, there is also increasing evidence that interval fasting can change the risk factors associated with obesity and diabetes.
- Studies of people on the Japanese island of Okinawa who fast regularly show a low rate of obesity, diabetes and a generally longer life for the test subjects. According to the research team, there are also indications that fasting could help people with heart diseases, the consequences of certain types of cancer, the prevention of Alzheimer’s and the relief of asthma symptoms.
- In patients with multiple sclerosis reduced Intermittent fasting symptoms in just two months, a research team in Baltimore reported in 2018.
Where does success come from?
But what makes abstaining from eating so healthy? Madeo and his team suspect that fasting triggers a kind of rejuvenation in the body. The lack of food therefore changes the metabolism of the cells: because they are not supplied with food, they look for other sources of energy and break down their own, including damaged reserves. The process is also called autophagy.
The positive effects of interval fasting could also be explained by evolution. Because: “Our human ancestors did not consume three regularly distributed large meals plus snacks every day and did not live seated,” explains the American researcher Mattson. Thus the natural interval fasting at that time was essential for survival. Nowadays, it is precisely this lifestyle that is so firmly anchored in society that experts overlook the health damage caused by sitting and eating too much, warns Mattson.
16 hours without food helps you lose weight
As for the success of losing weight: Mattson and his colleague write that it takes ten to twelve hours to consume the calories in the liver before a “metabolic shift” to using stored fat occurs. After meals, glucose is used for energy and fat is stored in the fat tissue. During fasting, fat is broken down and used for energy once the glucose is used up. If you want to lose weight, you should avoid eating for 16 hours.
The German scientist Madeo also emphasizes the scarce food stocks of our ancestors. And even those who eat a reduced calorie diet will only experience the benefits of the rejuvenation treatment if they stop eating completely from time to time: “Our physiology knows periods of hunger followed by excess food.”
This is how the interval fasting cure works
Matteo and his team are aware that many people find it difficult to avoid food for over 16 hours. But with instructions and a little patience everyone can integrate interval fasting into their lives. According to researchers, it takes up to a month to see and feel results and the body gets used to fasting: “Patients should be advised that the feeling of hunger and irritability is common at first and usually subsides after two to four weeks and body and brain get used to it, ”says Mattson.
To overcome this hurdle, Mattson suggests that doctors advise patients to gradually increase the duration and frequency of fasting periods over several months, rather than jumping into the cold water. What is also decisive is what you eat during mealtimes. According to Mattson, it’s important to drink plenty of water and eat healthy foods like vegetables, fruits, nuts, whole grains, fish and lean meats, and yogurt, and avoid sugar, salt, and fried foods.
According to researchers, anyone can start fasting at any time. Madeo advises not to fast in the event of a virus infection, however, as the immune system will probably need immediate energy to fight viruses.
Research is far from over
Even if the current studies attest that intermittent fasting has great health potential, the processes are not yet fully understood. Mattson admits that the researchers “don’t fully understand the specific mechanisms of metabolism”. This is followed by Thomas Pieber, Head of Endocrinology at the Medical University of Graz. “It is not yet clear why exactly calorie reduction and fasting have so many positive effects,” is his preliminary conclusion.
So questions remain unanswered – accordingly, research continues. The German research team around Madeo, for example, wants to continue to investigate the effects of alternate day fasting in various groups of people, including people with obesity and diabetes. The unanswered questions also repeatedly bring critics to the scene. Therefore, Mattson, who says he has been fasting at intervals for decades, is also very personally concerned with researching the long-term consequences.