Let’s start with the basics by defining what fasting is. Fasting involves suppressing solid foods from your diet for a longer or shorter period of time, forcing your body to use its reserves as a source of energy. It is a natural thing to do. So, it is not a fad or anything charlatans have just come up with. We will see that fasting has been a common practice since the dawn of humanity, recommended by the great sages of history.


  • To overcome emotional attachment to food.
  • To cure physical and mental stagnation, which manifests as poor appetite, apathy, fatigue, mental depression and many other chronic conditions.
  • To purify the body, as a first step to changing your diet for better health.
  • As a regular detox at the change of season, from summer to winter and from winter to summer.
  • For spiritual reasons, to strengthen spiritual practice, prayer or meditation, before or during those periods of ritual practice. In this case, it is recommended to avoid onions, leeks and garlic because, although they are rich in sulphur (very cleansing), they make it difficult to concentrate and connect between the two hemispheres of the brain.
  • To improve both mind and sleep.


The best time to fast is in spring or autumn, at the change of season, when the organs responsible for detox are most active, especially the liver in spring. This is confirmed by all natural medicine traditions, macrobiotics, Ayurveda, Taoism, etc.

Since the foods we eat in winter and summer are more extreme, it is good to fast as soon as those seasons come to an end to ease the transition to the more moderate seasons of spring and autumn. Fasting in the spring, for example, helps the body to discharge the heavy, fatty and salty winter foods and prepares it for the summer. Fasting in the autumn removes excess debris of sweet and cooling summer foods and prepares us for the winter season. A good thing to do in the autumn is fasting on whole grains or assorted vegetables alone. This fibre-rich fast is particularly good for the large intestine.


  • It helps the liver to detox.
  • It helps the intestines to discharge toxins, self-repair and rest.
  • It improves the function of the pancreas and glucose level in the blood are balanced.
  • The stomach recovers from inflammation.
  • Improved anxiety and depression.
  • Greater cognitive capacity and a more lucid mind.
  • The immune system has more energy.
  • Rest for T-lymphocytes.
  • Improved function of the spleen/pancreas, the kidneys recover from possible imbalances caused by poor digestion.
  • As regards the heart and the circulatory system, the blood becomes more fluid, the heart works more efficiently and the heart-kidney tandem is harmonized.

The mental and spiritual benefit of fasting is undeniable. All the great spiritual traditions throughout history, with their respective teachers (Jesus, Buddha, Plato, Pythagoras…) have promoted fasting as a way of spiritual growth, a way to find inner peace.

George Ohsawa, who introduced macrobiotics in the West, also insisted on the benefits of vivere parvo, of a simple and easy life, eating the necessary food in small amounts and practicing meditative chewing.


  • Use spring water and unprocessed, organic, seasonal and locally grown food.
  • Chew very well.
  • Your intuition will tell you how much liquid you should drink, which will increase considerably while you are fasting. However, when fasting on fruit, vegetables or whole grains, it is not advisable to eat until you are full up. Try eating no more than twice a day.
  • Make sure you get enough mental and physical rest and keep your body warm. If you feel cold, it’s good to add some freshly ground black pepper to whole foods or drink black pepper, dried ginger, cinnamon, fennel, fenugreek and/or rosemary infusions, as these are all naturally warming.
  • Complete a series of short fasts before attempting a long one.
  • It is advisable to make a smooth transition in and out of the fast. Gradually, certain foods will be removed from the diet. Firstly, animal proteins (meat and dairy) are removed, on the second day fish and eggs are removed, on the third day pulses and nuts are removed and finally, on the fourth day, cooked cereal grains are removed if necessary.

Fasting can focus on vegetables and/or vegetables and fruit. In some cases, we will keep the seeds, because their mucilage helps to protect the digestive tract and eliminate more toxins. When “coming out” of the fast, we proceed in the same way, but in reverse. Ideally, we should not return to our old habits, but take the opportunity to establish a healthier diet.

  • – For those who really “feel the cold“, the idea is to fast on whole grains (Ohsawa’s diet No. 7). If this is your case and you still seek detoxing on fruit and vegetable juices, you should introduce naturally warming spices such as cinnamon, ginger, cloves or nutmeg.
  • – On all fasts it is permitted to drink disharging soups or broths (using roots and seaweed) between meals.


  1. 0 FASTING: This is a diet based on oxygen. It consists of breathing, that´s all. It is ideal for people with symptoms such as fluid retention, candida, obesity, abundant mucus or sluggishness. It is not good for skinny, lean and feeble people. I do not recommend that you extend it beyond 36 hours (a day and a half) without prior preparation or supervision. It can be very effective. With this fasting in the given time, you generally achieve what with other fasts can take several days to achieve. No food or drink for 36 hours, starting at 6 or 7 p.m. and ending early on the second morning. It is the fasting which best stimulates concentration and mental clarity. Special attention is paid to breathing in a meditative way.
  2. LIQUID FASTING: Maximum 10 days and can be done without the need for rest (except for obese people and diabetics). It is based on cleansing broths or vegetables, freshly squeezed fruit juices, vegetable and fruit smoothies, sea water and herbal infusions. It is advisable to add flax seeds macerated in water overnight to provide mucilage.
  3. VEGETABLE AND FRUIT FASTING: Recommended for people who have eaten a lot of animal products and want to change to a full vegetarian diet. You may try this fast with salads containing raw vegetables and fresh fruit (carrots, cabbage, apples, etc.). It can last up to 15 days and no rest is required. In the cold season, lightly cook the vegetables or steam them. You can drink tea, water or herbal juices depending on how thirsty you are. In case of candidiasis, avoid fruit and its juices.
  4. CEREAL-GRAIN-BASED FASTING: This is G. Ohsawa’s famous “No. 7 diet“. It is suitable for a minimum of 3 days, up to 20 days. Small amounts of seaweed can be added (5g.). It is ideal for people who are usually hungry, who feel the cold, want to focus mentally and have a balanced or slim constitution. Each mouthful should be chewed 30 to 50 times. Apart from brown rice, other grains can be used. Millet goes very well because it is alkaline and detoxifying in nature. Wheat and other sprouted grains are also alkaline and less cooling when steamed. If you’re thirsty between meals, you may drink bancha or kukicha tea or a sip of hot miso broth. If you feel the cold you can drink naturally warming herbal teas such as cinnamon and dried ginger root. The ideal bread here is sourdough bread (whole grain) or sprouted bread.

Yogis often fast on mung beans and rice, which balance every aspect of the body and mind. Mung beans are better for fasting because they can remove toxins from your body. In addition, cooking them with a small amount of seaweed increases their detoxifying effect. The cold yin nature of mung beans can be neutralised for people who really feel the cold by adding warming spices in the last 20 minutes of cooking (black pepper, cinnamon, fennel, cumin and/or dried ginger powder).


Fasting involves responsibility and it is always advisable to rely on professionals. It is not suitable in the following situations:

  • In cold weather, prolonged fasting can be harmful.
  • During serious physical or mental degeneration, unless recommended by a qualified health professional.
  • During pregnancy or breastfeeding. The body during this period needs a healthy, tissue-rebuilding diet.
  • In the case of surgery or when there is more need for protein.
  • In patients under medication.
  • In type 1 diabetics fasting should be monitored closely.
  • In cases anxiety or psychosis.
  • In heart disease cases.
  • Patients with chronic illnesses should be monitored closely.


Intermittent fasting has grown very popular. It consists of having the same amount of food as you would normally have but over a shorter period of time. One of the most popular intermittent fasts is one in which out of 24 hours a day you eat for 8 hours (or less) and fast for 16 hours. During these 8 hours, you can distribute your intake as you wish (one, two or even three meals) and yet you should notice many benefits.


No one type of fasting is suitable for everyone. All fasts have their pros and cons, just as there is no one diet which suits everyone in all circumstances. The first figure refers to the hours of fasting and the second figure refers to the hours of food intake.

  • 23/1 (OMAD – “one meal a day”): This is the most appropriate one if you want to maximise the benefits of intermittent fasting. However, a very common mistake is to eat less during the “eating” hours, and this is counterproductive if you want to lose weight, as it slows down your metabolism. This type of fasting is ideal to improve food cravings, although this depends on each person’s situation.

On the other hand, it would be healthier to have just lunch instead of dinner (the latter is more practical than healthy). Eating too much can lead to problems (e.g. reflux, heaviness, inability to sleep, etc.). However, eating a lot in at midday will cause drowsiness (and this may not be very practical). The biggest problem with this fasting is that we should eat the same amount of food, not less, and logically this is difficult when we only have a short slot to do so. This is why it is perhaps better to fast for 20/4.

  • 20/4 – This would be the “middle way” between a 16/8 fast (with less benefits) and a 23/1 fast (with more benefits, but with the above-mentioned disadvantages). It may consist of an early dinner around 6 or 7 pm and then a supper according to your timetable.
  • 12/12 – consists of eating only for 12 hours and fasting for another 12. This fasting is quite easy and can be done simply by making an early dinner and delaying breakfast a little. As we see below, the benefits are not as profound.
  • 16/8 – is the most popular type of fasting. It can be done by skipping dinner or breakfast, depending on your timetable and preferences. Some people do it for long periods of time.


  • There is huge difference between simple and complex carbohydrates. I cannot stress this enough. I believe it is a very serious mistake to just refer to “carbohydrates”, not discriminating simple from complex. Their speed of absorption is very different. The emptier a carbohydrate is and the less fibre, fat and protein accompanies it, the greater its speed of absorption and consequently the greater its impact on your glucose levels in your blood (this will “wear out” the pancreas, which is responsible for regulating these processes). While simple carbohydrates are transformed into fat, and transported to be stored in your adipose tissue, complex carbohydrates are gradually released into the blood until they are used by the cells in the form of glucose, or stored in the liver in the form of glycogen.
  • Having said that, in intermittent fasting glycogen will be used up in about 12 hours. Beyond that, we will switch to using fat as an energy source (lipolysis), every obese person’s dream.
  • 12 hours onwards, there is also an increase in SIRT3 hormone, the benefits of which can be seen in the “hormetic zone” (maximum 24 hours). This “youth” hormone has been associated with multiple benefits for the body, increased metabolism and the formation of new blood cells.
  • 16 hours onwards, a process of “autophagy” begins, your body starts using the reserves in its tissues (circulating proteins and fats, etc.) as energy. Let’s say that the body’s “debris” is transformed into energy.
  • After 20 to 22 hours of fasting, there is already a lot of scientific evidence which shows that the amount of stem cells in the tissues increases. This means that they are renewed faster and in a more healthy way, as your body does not only detox, but also stem cells grow and “old tissue” is destroyed. In this case, a more beneficial anti-aging effect is produced.
  • Although you could do so, it is not necessary to eat less, or even change your diet. You just redistribute your food intake.
  • Long fasting makes sense once or twice a year, at times when we need to discharge or cleanse more intensively or specifically, or when we want to speed up healing a disease of bacterial origin.


  • In addition to losing weight, your total body fat percentage will drop.
  • It improves your relationship with food (cravings and snacking).
  • It improves your cognitive capacity, by increasing neurotrophin hormone.
  • Reduction of ageing, because it increases SIRT3, the “youth” protein, and reduces mortality.
  • It promotes autophagy (beyond 16 hours), another anti-ageing system, also in the brain.
  • It reduces triglycerides.
  • It improves brain cells plasticity.
  • It curbs cancer cell growth and makes chemotherapy more tolerable.
  • Promotes weight loss but not loss of muscle mass.


The general consensus is that there are no downsides to fasting beyond those mentioned above. If you fast for a longer period of time, put yourself in the hands of trusted professionals and take into account the following:

  • Toxines can be released in the bloodstream due to “fast” cleasing and detox.
  • Healing crises can occur.
  • Possible energy crashes.
  • Adaptation and/or advice is needed.
  • Possible headaches.


I have mainly tried 16/8 fasting. My main motivation was to solve digestive problems, discomfort and gas. I used to have very slow digestions and I can say that I have experienced many of the benefits mentioned above, especially in terms of mental clarity and vitality. I eat organic, seasonal and local products, I cook them following the guidelines I promote in my classes and workshops. I have felt much cleaner and more vital and I sleep better at night. My digestions have been much lighter and regular, with less bloating and gas. I’ve noticed special improvement in my relationship with food and a better chewing, as a meditative practice, taking advantage of the time to eat as a time for self-reflection and awareness.

However, with 16/8 fasting you have to be careful if you are quite skinny. I have noticed that this type of fasting, and even longer, 20/4 or 23/1 is not at all suitable for lean people, as is my case. This is because, as I mentioned above, from 12 hours onwards, lipolysis begins and from 16 hours onwards, autophagy begins. So, be careful if my case is yours. Look at yourself and check your energy and vitality levels and see how you feel until your next meal. My advice is for you to try and find your own way of fasting, if you should decide to give it a go.

What about you? Have you tried fasting? Have you experimented with intermittent fasting? How was it? Let me know!


I would like to stress that fasting should always be adapted to personal needs and lifestyle. Short fasts are more suitable when you have to continue with your normal daily activity. Long fasts should be controlled and take place during a retreat or in a relaxed environment. If repeated energy crashes occur, the fasting should be abandoned. After fasting, food should be gradually reintroduced as mentioned above and you could take advantage to improve your diet by introducing quality, organic food.

I hope you enjoyed this article. Remember that the information in this article is never a substitute for face-to-face consultation. Fasting may or may not be recommended, depending on the patient’s constitution, condition and specific circumstances. Please contact me if you require personalised attention.

Take care and see you soon!