Intermittent fasting is a popular lifestyle change that many people around the world follow in order to lose weight and improve their health, it is not a diet plan per se but a daily eating pattern. it acts through calories restriction throughout the day it is also called intermittent energy restriction it can be employed in many different ways by changing the meal timing schedules alternating between voluntary fasting periods of time when you abstain from eating only or eating and drinking and non-fasting periods through which you can consume all types of food without restriction.
History of fasting
Fasting has been around for centuries in many cultures of the world and in different religions over the centuries in a plethora of various forms and practices and for different reasons.
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- in Christianity, many people fast and pray as a means to increase spirituality and be more humbled by the presence of God to show obedience and submission to God. It’s not about self-denial.
- Buddhist monks are known to fast from noon till the next morning to learn how to control themselves and quench their human desires and raise their spirits above worldly aspirations
- Hinduism also embraces fasting for days and in many festivals as they believe that sins are forgiven when the body suffers and to direct their souls into spirituality and peace.
- Muslims are obliged to fast during the month of Ramadan as one of the five pillars of Islam and are encouraged to fast on Mondays and Thursdays from sunrise to sunset as a means of getting closer to God and learning moderation and learning to resist temptations and getting to understand how the poor life to encourage giving and empathy towards the needing.
Fasting as a means of losing weight and improving lifestyle has been employed recently in 2013 through the best seller book “the fast diet” by Michael Mosley which made it very popular in Europe and Australia, it describes the benefits of restricting energy intake for two days a week while eating normally through the rest of the week there are many other books with different types of fasting daily patterns and many scientific research papers talking about the importance of fasting and the many health benefits on the body.
A famous Johns Hopkins neuroscientist Mark Mattson who has been studying fasting for years has noticed that people in the past used to have lower obesity rates as they didn’t stay up late like we do in recent days , there were no entertainment options to make them stay up past 10 o’clock so people went to sleep earlier and stopped eating unintentionally ,but now we spend the entire night awake binge-watching shows and playing video games and consuming much food without noticing .in the past also people used to walk more and get out and do various physical activities that kept them fit and on their feet but now especially since the beginning of the covid pandemic people are obligated to stay home and work and learn online which makes them sit for hours and hours without any physical activity which is one of the main reasons for the higher rates of obesity that surged in the past couple of years which increases the risk of chronic disease as hypertension , diabetes and cardiovascular diseases .
Types of intermittent fasting regimens
There are many methods for people to follow intermittent fasting either fasting for somedays through the week and eating the rest of the week freely or fasting for some hours during the day and eating without restrictions in the remaining hours, some people fast from food completely or food and water and some eat very little with a predetermined amount of calorie restriction. Some of the most popular methods are:
1) 16/8 method:
It is one of the most popular methods of intermittent fasting that a lot of people choose to follow over other methods as it is the easiest most straightforward way. it involves fasting for 16 hours and eating for the remaining 8 hours of the day while making sure to skip breakfast so most people eat from the afternoon till about 9 p.m. and sleep for 8 hours then fast for the next 8 hours of the morning .
Another name for this method is (the leangains protocol) this is a very good example of time-restricted feeding protocols as it follows the circadian rhythm that naturally controls the metabolic rate of food which is higher during the day and lower at night. You can drink water, coffee, or tea during the fasting hours to reduce hunger and during the eating hours, you should choose nutritious food with fewer calories and more health benefits.
2) 20/4 method:
Another method very similar in concept to the 16/8 method but it requires fasting for longer periods of time you are supposed to fast for 20 hours, and you can eat for the remaining 4 hours of the day it is also called (the warrior diet) and this type of diet is designed in phases:
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- the first week or phase one the aim is to detox your body by eating very little and drinking water, coffee, tea during the 20 hours fasting period then you break your fast with healthy but hearty meals with many fruits and vegetables in the 4 hours you got
- In the 2nd week or phase 2 you can do the same thing as the first week during the fasting 20 hours period but in the 4 hours of eating you should try to restrict carbohydrates and starches as much as possible and consume more fat and protein to lose more weight
- the last week or phase three where you do the same for the 20 hours fasting period as the past two phases but in the 4-hourwindow of eating you are supposed to alternate everyday between carbohydrates and proteins. this high carb high protein cycle is supposed to finalize the weight loss journey and you start the 3 phases all over again at the end of the three weeks to keep the weight off.
3) The 12 hoursfast:
The easiest method to follow for people who find it hard to fast for long periods of time you basically fast for half of the day and eat during the remaining half
what’s good about this plan is that many people sleep for most of the fasting period which makes it easier to pass and makes it more likely for people who usually hate fasting stick to this plan for longer as it requires almost no effort which takes off the burden of fasting while giving almost the same amount of benefits.
4) 5:2 method:
This method is a different approach to intermittent fasting as it splits the weekdays into 5 days where you eat normally and 2 non-consecutive days where you only consume 500_600 calories so it is not time restricting it is a calorie restricting plan it is also called (periodic fasting) or( the fast diet) which became popular in recent years by Michael Mosley’s book.
It highly encourages choosing high fiber high protein foods during the fasting period to get the most nutrition and to feel full for longer periods of time it also encourages to not compensate the fasting days by overeating during the other 5 days but be more mindful about the types of food you consume in modest amounts.
5) Alternate day fasting method:
This is a straightforward method of intermittent fasting where you fast for a full 24 hours without food, but you can drink unsweetened coffee, tea, or water basically any calorie-free beverage about every other day, and eat freely for the next day.
There are many variations to this method some people don’t fast completely but restrict their caloric intake to 25 % of their energy requirements consuming about 500 calories on fasting days which makes this plan more sustainable and tolerable than full fasts, but it was found that alternate-day fasting didn’t produce superior weight loss results compared with daily calorie restriction over time and many people found it very difficult to follow for a long time.
6) The 24 hoursfast:
This variation is similar to alternate-day fast but you do it steadily once or twice a week where you fast for full 24 hours then have a feast day where you eat all you want on the following day there are no solids allowed in the fasting day but you can have calorie-free beverages and make sure to stick to a stable nutritious diet during the eating days and not compensate for the fast by overeating so as not to put on more weight.
7) The OMAD METHOD:
The one meal a day (OMAD) method is a very strict way of intermittent fasting that some people follow, they usually fast for 23 hours a day and have a 1-hour eating window left where they eat all the types of food they want in whatever amounts they desire there is no calorie restriction at all but it is very difficult to sustain and you feel hungry and lose focus most of the day as your sugar levels get very low so it is not ideal for everyone.
8) Spontaneous meal skipping method:
This is a carefree way of trying intermittent fasting without sticking to a specific preset eating plan it is totally dependent on your mood and daily routine. you can skip a meal or two during the day like breakfast for instance if you don’t feel hungry enough or if you are too busy to prepare a meal and be doing this from time to time you restrict calories in a way that is stress-free and spontaneous.
Benefits of intermittent fasting
1. Circadian biology:
All mammals have a natural biologic clock in their bodies to control their circadian rhythm through restricting activity during the night and being more active in the morning.
the time of day and the amount of light present around are the main controllers of this rhythm through their action on the suprachiasmatic nuclei in the hypothalamus which are in sync with the peripheral tissues own clocks that control the integration of metabolism and energy along with physiologic indices as hormonal secretions, physical coordination, and sleep.
it is hypothesized that an imbalance between those two circadian clocks can lead to energy imbalance and increase the risk of many chronic diseases like obesity, diabetes, cardiovascular disease, and cancer that is where the role of time-restricted feeding in intermittent fasting shines as it helps the body regain its natural diurnal rhythm of food intake resulting in a better oscillation of the circadian clock that improves metabolism and body weight regulation.
2. Gastrointestinal microbiome:
Intermittent fasting through its restriction of food during the night enhances food digestion and metabolism as gastric emptying and gastrointestinal secretions and blood flow are way greater during the daytime than at night .it also directly influences the gut microbiome which is a complex and variable community of microorganisms that reside the gastrointestinal tract and are responsible for absorption of the toxins from the body and enhancing the overall health of the GIT.
studies have found that microbiota in obese people harvests more energy from the diet than in lean people which makes obese people need more energy absorption and storage another important factor is obesity-related gut changes that increase the permeability of the gut and promotes bacterial translocation one of the hallmarks of obesity-related inflammatory activity and the cause of many obesity-related comorbidities.
3. Promotes weight loss:
Intermittent fasting is a great lifestyle change that if done the right way can result in many health benefits and make you lose weight .by fasting you restrict your daily caloric intake if you focus on mindfully choosing the right ingredients to put in your meals and if you don’t compensate the fasting hours by overeating and consuming more food when you eat, you can definitely lose weight easily.
intermittent fasting also enhances hormones functions that lead to weight loss through lowering insulin levels and increasing norepinephrine which increases fat cells breakdown and usage as a source of energy and this loss in visceral fat will give you a smaller waist circumference and boost your energy levels and lowers your risk of having chronic diseases like obesity, hypertension, diabetes and heart diseases.
4. Reduces insulin resistance in type 2 diabetes:
High blood sugar levels due to insulin resistance is one of the main type 2 diabetes mellitus causative factors. intermittent fasting is effective in lowering fasting glucose and insulin levels and decreasing the risk of insulin resistance it also decreases the level of leptin and increases the level of adiponectin and lowers the level of CRP and diabetes-associated inflammation.
as insulin levels decrease the build-up of fat in adipose tissue decreases which leads to weight loss and lower rates of complications associated with obesity and diabetes from macrovascular complications like atherosclerosis, coronary artery disease, and strokes or microvascular complications like renal glomerulopathy, eye retinopathy, and peripheral vascular disease.
5. Promotes cardiovascular health:
As fasting has positive effects on many of the causative risk factors of heart disease it has been shown to decrease the risk of coronary artery disease and atherosclerosis through lowering blood pressure and creating a better lipids profile that is lower on triglycerides, cholesterol, low-density lipoproteins LDL and higher on high-density lipoproteins HDL along with its positive effect on blood sugar levels and inflammatory markers. fasting for sure enhances heart health.
6. Repairs cells through autophagy:
One of the main areas of interest in fasting is the effect on cells. Fasting not only allows the body to heal but also helps the body get rid of the accumulated defective cells and proteins what is known as autophagy which basically means waste removal that makes the cells recycle the nucleus with the DNA and mitochondria which produces energy and lysosomes which remove waste from cells to free up building units to use for making new healthy cell components and increase the lifespan of the newly formed cells while getting rid of the defective destructed old cells by that it rejuvenates the whole body and lowers the risk of many diseases like cancer and neurodegenerative disorders like Alzheimer’s disease.
7. Lowers oxidative stress:
Fasting cleans the body from the accumulated effects of free radicals and reactive oxygen species that damage the cells and destroys the DNA structure leading to many mutations and more frequent bouts of inflammation by choosing the right types of colorful healthy nutritious food that is rich in antioxidants you help the body function more properly with faster more efficient damage repair.
8. Enhances brain health:
Fasting helps the cells stay young and cleanses the body from the build-up of toxins that harms the brain and leads to aging it also helps the brain build more synapses and have better cognitive function and memory and with the added benefit of lower inflammation and better vascular health it lowers the risk of strokes and neurodegenerative diseases like dementia.
9. Decreases risk of metabolic syndrome:
Intermittent fasting along with the right daily healthy habits can greatly lower the risk of obesity and associated diseases from hypertension, cardiovascular disease, and diabetes which are known to lower the quality of life and makes your life expectancy shorter.
10. Helps fight cancer:
Many studies have shown the great effect of fasting on cancer and immunotherapy in fact fasting makes the immunity stronger through autophagy, as it gets rid of the mutagenic cells and helps enhance the effect of immunotherapy making treatment more effective in fighting cancer and increasing lifespan and resulting in overall better prognosis.
11. Enhances mood:
Fasting has been proven to improve mental health as it teaches you patience, gratitude, makes you appreciate the importance of food, and makes you look forward to planning your meals to be as tasty as possible as a reward for your long fast. it also teaches you willpower, determination and gives you a feeling of satisfaction at the end of the day that you managed to pull through till you finished the whole fast.
Risks of intermittent fasting
◉ Intermittentfasting can be dangerous for people with diabetes mellitus who are using insulin or oral insulin secretogages like sulphonylureas which increases the risk of getting hypoglycemic attacks easily, so it is advised for people with diabetes to not fast for too long so as not to have sudden attacks of sugar crashes if their diabetes is not properly controlled.
◉ A very important factor to consider while fasting is choosing the right type of nutrients to have a healthy meal plan that supplements you with all the minerals and vitamins you need as many people focus on loading up on carbs and forget to get the right amount of vegetables and fruits so many of them suffer from deficiencies that requireproper supplementation
◉ Protein is also an important factor to consider as many people can lose a ton of muscle weight and becomewasted if they don’t supplement their food with the right amount of protein to build up muscle and get all the essential amino acids the body needs.
◉ Many intermittent fasting regimens allow fluid intake during the fasting period as long as it is calories free like water, tea and coffee withno added sugar; as they fear the harmful effects of dehydration but many people forget to drink enough during these fasts which lead to dehydration and excessive hunger pains, dizziness, weakness, nausea, insomnia, migraines, hypotension, and even syncope attacks so it is very important to drink at least 2 to 3 liters of water during the day for the body to function properly especially for people who suffer from chronic diseases and those at risks of strokes.
◉ There are special groups of people who should altogether refrain from fasting as it can be a heavy physiological load on their bodies and could endanger their lives if done with no supervision mainly old aged people, pregnant and lactating females as they require a higher caloric intake for the fetus to grow and develop in a healthy way,any adult who suffers from a debilitating disease that compromises their way of living, anyone who is immunosuppressed those suffering from AIDS or on immunosuppressive therapy or having had an organ transplant, people with dementia and people suffering from eating disorders can have very bad exacerbations of the disease if not careful, those who have a traumatic brain injury or post-concussion syndromes should refrain from fasting as it can make their condition worse with higher rates of adverse effects.