Intermittent fasting for a longer life: Science, methods and myths
Did you know that 67 percent of people in Germany believe that intermittent fasting makes sense from a health perspective? This life-prolonging measure, which includes phases of food intake and fasting, is becoming increasingly popular. Scientific studies and testimonials suggest that fasting could offer benefits such as weight loss, improved heart health and reduced inflammation. But what is really behind these claims?
Intermittent fasting, in which food is restricted for a certain period of time, can be carried out in various ways. Some of the best known methods are the 16:8 method and the 5:2 diet. These approaches are being closely studied from both a health and scientific perspective to understand the actual benefits.
Important findings
- 67 percent of Germans consider intermittent fasting to be beneficial to their health.
- Intermittent fasting includes various methods, such as the 16:8 method and the 5:2 diet.
- Fasting can provide benefits such as weight loss and improved heart health.
- During fasting, a cellular recycling process called “autophagy” takes place.
- However, there are also risks and myths associated with intermittent fasting that should be considered carefully.
The science behind intermittent fasting
Intermittent fasting has aroused great interest in the scientific community. Numerous studies have shed light on how it influences various biochemical processes in the body and therefore offers numerous health benefits.
Metabolism and autophagy
Intermittent fasting leads to profound changes in the metabolism. During fasting, the body switches from burning glucose to burning fat, which leads to increased ketone production. These changing metabolic states activate the autophagy process, in which cells break down and recycle their damaged components. This response is crucial for healthy cell function and has been observed in a number of studies, including research at Immanuel Hospital, where around 1500 fasting patients are cared for each year.
A clinical study with 150 participants showed that intermittent fasting has similar effects on metabolism and weight loss as a normal reduction diet. Participants who followed the 5:2 fasting principle consumed 20 % fewer calories per week and achieved important metabolic improvements, including improved insulin sensitivity and a reduction in abdominal and liver fat.
Positive effects on the immune system
Intermittent fasting also has remarkable positive effects on the immune system. The autophagy process helps to eliminate damaged cellular components, which can lead to a reduced inflammatory response. Various studies, including research by Dr. Andreas Michalsen, who follows 500 intermittent fasters annually, highlight that fasting can boost the immune system by reducing inflammatory parameters.
In a pilot study, cancer patients who fasted before and after chemotherapy experienced a significant reduction in fatigue and improved quality of life. These results give hope that intermittent fasting offers invaluable benefits for the immune system and general well-being.
Different methods of intermittent fasting
Intermittent fasting offers different methods, each with their own advantages and disadvantages. The most popular fasting methods are the 16:8 method, the 5:2 diet and the Eat-Stop-Eat method. Each sets different priorities in terms of eating and fasting times.
16:8 method
The 16:8 method is one of the best-known fasting methods. It involves a daily fast of 16 hours and an eating window of 8 hours. Two meals can be consumed within these 8 hours. Studies show that this method helps to regulate insulin levels and promote fat metabolism.
5:2 Diet
Another popular fasting method is the 5:2 diet. Here, participants eat normally on five days of the week, while calorie intake is restricted to 500-600 calories on the other two days. For women, a reduced energy intake of 400-500 calories is recommended, while men can consume 600-700 calories. This diet is said to be particularly effective for weight loss and improving insulin sensitivity.
Eat-stop-eat method
The Eat-Stop-Eat method involves fasting for 24 hours once or twice a week. This method is often chosen to establish new eating habits and encourage the body to use fat reserves. During the fasting period, calorie-free drinks are allowed so that the feeling of hunger is kept to a minimum.
These fasting methods are flexible and can be adapted to individual needs, which makes them particularly popular. Many users also report increased energy and improved mindfulness in everyday life.
Fasting: a method for longer life
Intermittent fasting is increasingly recognized as a promising method for prolonging life and promoting healthy ageing. This can be seen, for example, in the reduction of calories in laboratory rats, which increases their average life expectancy by up to 50 %. Equally remarkable is the fact that the inhabitants of the Japanese island of Okinawa, who have the highest life expectancy in the world, consume significantly fewer calories than the rest of Japan. Their philosophy of life “Hara hachi bu – eat only so much that you are 80% full” illustrates this impressively.
It has been scientifically proven that the body needs about 1-2 days without food intake to switch from glycogen reserves to fat burning. Thus, intermittent fasting, especially the 16:8 regimen, supports longevity and healthy ageing. There is evidence that resveratrol promotes sirtuin activation, a key role in prolonging life through calorie restriction, as demonstrated by David Sinclair in the 2000s.
Results from studies show that regular fasting in organisms such as yeast, fruit flies, mice and rats leads to a 20-50% increase in life expectancy. Alternate day fasting (ADF), which involves fasting every other day, is also recognized as effective in the scientific literature. This can also be seen in experimental studies such as the Graz InterFAST study, which investigated the effects of alternate day fasting on the ageing process. In the long term, fasting leads to a reduction in inflammatory parameters in the blood and a reduction in weight through the breakdown of fatty tissue, which has an overall positive effect on health and lifespan.
The average life expectancy of Okinawans, which is characterized by conscious food intake and moderate calorie intake, provides a real-life model. Fasting thus remains the only method of life extension that has been confirmed in all organisms studied to date (except humans) and represents a promising strategy for longevity and healthy ageing.
The health benefits of intermittent fasting
Intermittent fasting has numerous health benefits that make it a popular method for many people worldwide. As well as promoting weight loss, it has a positive impact on metabolism, improves heart health and has the potential to reduce inflammation and support the healing process.
Weight loss and metabolism
A significant benefit of intermittent fasting is weight loss. By fasting and then eating within limited time frames, such as the 16:8 method, calorie intake is automatically reduced. This leads to a reduction in visceral fat and optimizes the metabolism. Studies show that intermittent fasting can improve fat metabolism and increase the insulin sensitivity of cells. In addition, intermittent fasting could stimulate the formation of new insulin-producing cells in the pancreas.
Improving heart health
Another significant benefit of intermittent fasting is the improvement in heart health. Research suggests that this method can lower blood pressure and regulate cholesterol levels. In addition, intermittent fasting can reduce the risk of diseases such as type 2 diabetes and metabolic syndrome, which are closely linked to heart disease.
Reduction of inflammation and promotion of healing
Chronic inflammation is the cornerstone of many life-threatening diseases. Intermittent fasting helps to reduce inflammation and supports the healing process. Studies indicate that fasting can increase the production of the hormone BDNF, which has an antioxidant effect and thus contributes to the reduction of inflammation. In addition, studies on breast cancer patients show significant decreases in tumor markers after a 5:2 diet.
| Health advantage | Explanations and studies |
|---|---|
| Weight loss | Reduction of visceral fat, improvement of fat metabolism, increase in insulin sensitivity |
| Heart health | Lowering blood pressure, regulating cholesterol levels, reducing the risk of metabolic diseases |
| Inflammation reduction | Increase in BDNF production, antioxidant effects, decrease in tumor markers |
The principle of autophagy and its significance
Autophagy is a vital biological process that contributes significantly to cell regeneration and supports healthy ageing. This mechanism enables cells to break down and recycle damaged or superfluous components. Yoshinori Ohsumi was awarded the Nobel Prize in Physiology or Medicine in 2016 in recognition of his significant discoveries in this field.
Scientific research has identified 15 key genes that are involved in autophagy. The activation of these genes allows cells to use their own energy reserves, especially when insulin levels are low. This is particularly relevant in methods such as intermittent fasting, where autophagy is promoted after about 11 to 12 hours without food intake.
Research on cell regeneration shows that autophagy plays a key role. When there is a nutrient deficiency, autophagy is activated and helps to eliminate defective enzymes and damaged DNA, which helps to maintain cell health. Studies suggest that this process may slow down aging, leading to a longer, healthier life.
Here are some relevant facts about autophagy at a glance:
| Aspect | Scientific findings |
|---|---|
| Nobel Prize | 2016 to Yoshinori Ohsumi |
| Genes involved | 15 essential genes |
| Research results | Autophagy-deficient mice develop tumors more frequently |
| Autophagy inhibitors | Hydroxychloroquine blocks autophagy |
| Cell renewal | Autophagy promotes cell repair and renewal |
Myths and misconceptions about intermittent fasting
Intermittent fasting has gained popularity in recent years, but there are many fasting myths and concerns, particularly around detoxification. There are numerous misconceptions circulating about the health benefits of fasting. Two of these common myths are “detoxification” and the use of fasting for chronic diseases.
Detoxification and “purification”
The term ‘detox’ and the concept of ‘purification’ are widely used to suggest that intermittent fasting can help rid the body of toxins. However, there is no scientific evidence that our bodies actually accumulate “waste” that requires detoxification. In reality, our bodies have their own very efficient method of detoxification, mainly through the liver and kidneys.
In addition to the lack of scientific basis for these fasting myths, many studies show the actual benefits of fasting: from improving insulin sensitivity to reducing inflammatory parameters. For example, a study from 2015 documented that intermittent fasting can positively influence blood lipids, body weight, body fat and insulin sensitivity.
Fasting for chronic diseases
Another misconception about intermittent fasting concerns its use for chronic diseases. While fasting offers many health benefits and studies show that it has positive effects on various lifestyle diseases, it is not suitable for everyone. Particular caution should be exercised with certain chronic diseases. People with metabolic syndrome may benefit from an improvement in blood pressure, as studies show, but other chronic diseases could be negatively affected by prolonged periods of fasting.
It is particularly important to seek medical advice before starting intermittent fasting if you have a medical condition such as diabetes or cardiovascular problems. In addition, studies suggest that female hormones can react more sensitively to changes in diet, which requires particular caution in women. An Indian study from 2013, for example, showed that prolonged fasting in female rats led to hormonal imbalances and the absence of periods.
Overall, it should be noted that intermittent fasting is a promising method for promoting health, but like any diet should be approached with caution and sound knowledge.
| Study | Result |
|---|---|
| Indian study 2013 | Hormonal imbalances in female rats |
| Study 2015 | Positive effects on blood lipids, body weight and insulin sensitivity |
| JAMA study 2017 | Weight reduction for obesity |
| Study 2021 | Possible therapy option for cardiovascular diseases |
Intermittent fasting and healthy eating
With intermittent fasting, it is not only the fasting phase that plays an important role, but also the quality of the diet on the days you eat. A healthy diet is crucial in order to make the most of the health benefits of fasting.
Food selection on meal days
The choice of food on meal days should be made consciously. It is advisable to eat a balanced diet that is rich in nutrients. Fruit, vegetables, wholegrain products, lean meat and fish as well as healthy fats and oils should be the focus. It is particularly important to avoid highly processed foods and sugar in order to keep blood sugar levels stable.
A 2015 meta-analysis showed that intermittent fasting is a valid, but not superior, alternative to continuous energy restriction in terms of weight loss and improved glucose homeostasis. This illustrates that the quality of food on meal days also has a major influence.
Organizing fasting days correctly
On fasting days, it is particularly important to drink enough fluids. Water, unsweetened tea and coffee are good options here. With the 5:2 method, women can consume 500 to 800 calories and men 600 to 850 calories on fasting days. This means that small, nutrient-rich meals, such as vegetable soups or salads, can be spread throughout the day.
However, people with low blood pressure, metabolic disorders or other chronic illnesses should consult a doctor before starting intermittent fasting in order to avoid possible risks. Pregnant women, breastfeeding mothers and people with eating disorders should also be excluded from fasting cures.
The benefits of intermittent fasting can be maximized by consciously structuring the fasting days and eating a healthy diet on meal days. A well-thought-out diet can help the body to respond better to the fasting phases and optimally support the metabolism.
The risks and side effects of intermittent fasting
Although intermittent fasting promises numerous health benefits, it also carries certain risks. The most common risks of fasting include nutrient deficiencies, disordered eating patterns and hormonal imbalance. According to a study from Shanghai, intermittent fasting increases the risk of dying from cardiovascular disease by 91 percent. These results are based on the eating habits of over 20,000 Americans who took part in the NHANES national nutrition survey between 2003 and 2018. However, critics of the study note that the data of 31 cardiovascular deaths is not sufficient to clearly substantiate the 91 percent.
Another key issue is the side effects of fasting, which can vary from person to person. People who eat within a window of eight hours or less each day have a higher risk of dying from cardiovascular disease. In particular, people who have already been diagnosed with cardiovascular disease and eat within a 10-hour period every day have a 66 percent higher risk of dying.
Interestingly, the risk of dying from cancer in cancer patients decreases if food intake is spread over more than 16 hours a day. This shows that intermittent fasting is not equally good or bad for everyone and that fasting precautions must be weighed up individually. Smokers and people with a high body mass index (BMI), for example, may be more affected by the negative consequences of fasting.
It is also advisable to work with a nutritionist during longer periods of fasting, especially if dietary supplements are to be taken. This will help to avoid possible deficiencies and make the most of the health benefits of fasting.
| Method | Calorie intake | Meal/fasting times |
|---|---|---|
| 16:8 method | Normal calorie intake | 8 hours of eating, 16 hours of fasting |
| 5:2 Diet | Women: 500-800 kcal, men: 600-850 kcal | Eat normally for 5 days, fast for 2 days |
| Alternating fasting | 25% of the usual calorie intake | Eat 1 day, fast 1 day |
As can be seen from the various methods and their effects, the risks of fasting and the side effects often depend on the individual circumstances and the method chosen. Therefore, fasting precautions should always be considered to avoid health problems and to take full advantage of the positive effects of fasting.
Intermittent fasting: who it is (not) suitable for
Intermittent fasting, also known as intermittent fasting, is becoming increasingly popular. However, suitability for fasting varies greatly and should be considered on an individual basis. People with certain health problems such as diabetes, low blood pressure or eating disorders should refrain from this style of eating. Pregnant and breastfeeding women and people who need to take certain medications should also be cautious. It is advisable to practice intermittent fasting only under medical supervision.
The best-known methods of intermittent fasting, such as the 16:8 method and the 5:2 diet, offer many health benefits, but they are not equally suitable for everyone. Studies have shown that the 16:8 method is largely safe for healthy people, as it involves a regular eating period and is therefore easier to integrate into everyday life. On the other hand, the 5:2 and 3:4 methods in particular are more difficult to manage, as evidenced by higher drop-out rates.
Nevertheless, there are clear contraindications to fasting. People with chronic illnesses, metabolic disorders or people with low blood pressure should be careful. The elderly, children and adolescents, as well as people who are underweight or have eating disorders are also groups for whom intermittent fasting is not suitable. Personal health should always be a priority and medical advice is essential for those interested in intermittent fasting.
