The power of fasting
Fasting and intermittent fasting have, as you've probably noticed, become a popular lifestyle trend in recent years. Numerous studies show that fasting can have positive effects on insulin sensitivity, energy management, and the body's recovery mechanisms, among other things [1, 2]. A crucial aspect is often overlooked: the differences between men and women. While men generally respond fairly stably to fasting, the hormonal cycle plays a major role in women's lives. This means that fasting can offer benefits for women, but also carries risks. In this blog post, we'll delve into what fasting exactly is, its known benefits, the various methods available, the differences between men and women, and offer practical tips.
What is fasting and what is intermittent fasting
Fasting is as old as humanity itself. In the time of hunter-gatherers, food simply wasn't always available. Their bodies were accustomed to periods of scarcity and abundance. Religions also recognize fasting as an important ritual. Think of Ramadan in Islam, Lent in Christianity, or Buddhist traditions. Fasting is therefore not just a cultural tradition but also aligns with the natural rhythms of the human body.
Intermittent fasting (IF) is the modern translation of this. It's an eating pattern in which you alternate between periods of eating and fasting. The focus isn't so much on what you eat, but rather on when you eat.
What are the benefits of fasting?
Fasting can have several positive effects on your body and health. First, it can help improve insulin sensitivity. This means your body can process carbohydrates from food more efficiently, which is beneficial for energy and prevents spikes and dips in your blood sugar. Fasting also affects your metabolism. During fasting, your body switches to burning stored fat as an energy source, which helps maintain a healthy body weight. Because we can eat throughout the day these days, our glycogen stores are continuously replenished. As a result, the body primarily burns carbohydrates instead of fat, and excess energy is stored as fat reserves. Fasting gives your body the opportunity to restore this energy balance and relearn how to burn fat.
Fasting can also stimulate repair processes in the body. During periods without food, your cells get the chance to clean themselves up. Damaged components and waste products are broken down and replaced with new, healthy components. This process is called autophagy and can be seen as a kind of cleansing of the body. Autophagy usually occurs after about 12 to 16 hours of fasting, when the body's glucose stores begin to deplete and it switches to burning fat. This process supports cell renewal and can contribute to a healthy aging process.
Research also shows that intermittent fasting can lower blood pressure and has a positive effect on brain function and alertness. Fasting also reduces oxidative stress and inflammation in the body, which can reduce the risk of chronic conditions such as cardiovascular disease and type 2 diabetes.
It's important to know that the effects can vary from person to person. Men generally respond fairly consistently to fasting. Women, on the other hand, can sometimes experience different results due to hormonal fluctuations. Therefore, it's wise to always tailor fasting to your own body and needs.
What methods of fasting are there?
There are several forms of intermittent fasting. The most common are:
16/8 method
A fasting method in which you don't eat for sixteen hours and eat all your meals within an eight-hour period. For example, you eat between 11:00 AM and 7:00 PM, and then fast from 7:00 PM to 11:00 AM.
5/2 method
With this type of fasting, you eat normally for five days. On the other two days, you limit your calorie intake to a maximum of a quarter of your energy needs. These two fasting days cannot be consecutive. For example, you might choose Monday and Thursday.
Alternate day fasting
A form of intermittent fasting where you alternate between a normal day of eating and a fasting or severely calorie-restricted day (max. a quarter of your energy needs). Your weekly schedule might look like this: fasting on Monday, normal eating on Tuesday, fasting on Wednesday, and so on.
Full-day fast
With a full-day fast, you eat absolutely nothing for 24 hours. So, you eat nothing from dinner until dinner the next day.
Long-term fixed
A prolonged fast is one that lasts longer than 48 hours. You don't eat anything at all for two days.
Whatever form you choose, it's important to ensure a nutritious and varied diet during mealtimes. Your body needs to get all the nutrients it needs during that limited time.
What is the difference between men and women during fasting?
First of all, it's important to know that men and women have completely different cycles. While men have a 24-hour cycle, women have one that averages 28 days. The female cycle is divided into three phases: the follicular phase, during which menstruation also occurs (days 1-13), ovulation (day 14), and the luteal phase (days 15-28).
Different hormones dominate in each phase. For example, the main sex hormones (estrogen, progesterone, and testosterone) are at their lowest on day 1 of the cycle. Estrogen levels rise during this phase. Given a woman's hormone levels at this time, fasting is considered safe. This means longer fasts are possible. During ovulation, estrogen and testosterone dominate, allowing for moderate fasting. This could include intermittent fasting of 16/8 cycles. After ovulation, it seems best not to fast as a woman.
During periods when fasting is safe for women, it's important to focus on healthy proteins and fats in your meals, but to limit carbohydrates. This is because the hormone estrogen is at its highest during this time. Estrogen functions best when blood sugar fluctuations are minimal, so it's wise to reduce carbohydrate intake. During other periods, it's good to eat meals that contain slightly more fiber-rich carbohydrates. This could include adding some sweet potato, seasonal vegetables, or extra fruit to your meals.
How do you prepare your body for fasting?
Make sure your last meal includes plenty of protein, healthy fats, and fiber-rich carbohydrates to prevent severe blood sugar fluctuations and make it easier to maintain the fast. For example, you could eat a piece of wild salmon with quinoa and some seasonal vegetables. Avoid too much salt, as it can cause your body to retain fluid. Also, make sure you drink plenty of fluids in the days leading up to the fast to maintain your mineral balance.
How do you break your bond?
During a short fast (less than 48 hours), you can eat a full meal right away. It's important to focus on a meal that's probiotic-rich and protein-rich, but also contains healthy fats. Think of a good piece of meat sauerkraut with some raw sauerkraut.
If you choose to fast for an extended period (48 hours or more), it's important to break your fast responsibly. This is because fasting for 48 hours or longer is enough to significantly slow down your digestive system. You want to gradually reintroduce solid food to prevent gastrointestinal problems. These four steps will make it easier for you to reintroduce solid food:
- Start with bone broth. After drinking a cup, it's important to wait an hour.
- Eat something with probiotics and healthy fats. This might include some raw dairy. After eating, wait another hour.
- Add some fiber. It's important to choose prepared vegetables for this, not raw salads. Wait another hour.
- You're ready to eat a full meal. Make sure you eat enough protein to stimulate muscle growth.
When Fasting Isn't Wise
Fasting isn't suitable for everyone. For example, it's not recommended during pregnancy or breastfeeding, as your body needs extra nutrients. Fasting is also less advisable if you have a low body weight or are prone to eating disorders. People with low blood sugar or type 1 or 2 diabetes should be extra careful. It's also important to be careful if you participate in high-level sports or do strenuous physical work. During intense exercise, your body needs a lot of energy and nutrients to perform well and recover. Prolonged fasting can deplete glycogen stores, which can reduce strength, endurance, and concentration, and slow recovery. The risk of muscle breakdown can also increase if insufficient energy and protein are available. If you have health problems or are taking medication, it's always wise to first consult your doctor about whether fasting is suitable for you.
Practical tips
- Build up your fasting slowly and see how your body reacts.
- Drink plenty of water, tea, and possibly coffee without additives. Consider electrolytes, especially if you're fasting for longer than 14 hours.
- Avoid intense exercise. Gentle exercise, such as walking and yoga, is often better during longer fasting periods.
- Avoid fasting during stressful periods, such as lack of sleep and high workloads.
- Make sure you eat nutritiously when you're not fasting. This means plenty of protein, healthy fats, and fiber-rich carbohydrates.
Book tips
- “Fast Like a Girl” by Dr. Mindy Pelz
- “The Dr. Ludidi Fasting Method” by Samefko Ludidi
References
[1] Vasim, I., Majeed, C.N., & DeBoer, M.D. (2022). Intermittent fasting and metabolic health. Nutrients , 14 (3), 631. DOI: 10.3390/nu14030631
[2] Hales, C. N., Garland, P. B., & Randle, P. J. (1963). Newsholme EA: The glucose fatty acid cycle: its role in insulin sensitivity and the metabolic disturbances of diabetes mellitus. Lancet i: 7285¿ 7289 . Doi: 10.1016/s0140-6736(63)91500-9
