Fasting is an age-old tradition practised for centuries for soul purification & body cleansing. It is a well-known practice in cultures & religions like Hinduism, Buddhism, Jainism, Islam, Christianity, and Judaism. However, the past decade has witnessed intermittent fasting as one of the most popular fitness & health trends globally. It has moved beyond rituals and has established itself to be effective in improving & maintaining a healthy lifestyle, promoting weight loss, and increasing longevity.
Intermittent fasting or energy restriction involves abstaining from eating either partially or entirely for a stipulated time before resuming a regular eating schedule. It can last anywhere between 12 to 40 hours. It would be best to refrain from consuming calorie-containing drinks or solid food during this period. Instead, you can opt for water, black coffee, or any other calorie-free beverage.
Here is the general concept with an example. For a 24-hour fasting regimen, if someone finishes the meal by 7 pm Monday, the next meal is instructed on Tuesday after 7 pm. The time frame chosen for intermittent fasting depends on the person, and it can last from lunch to lunch or breakfast to breakfast.
In its most conventional sense, intermittent fasting governs when you should eat. Hence, this form of calorie restriction becomes a part of an eating pattern. You can classify intermittent fasting into types depending on the calorie allowance and duration. The choice of which calorie-restricting diet yields the best result is decided by finding the most suitable diet according to your lifestyle.
Types of Intermittent Fasting
The five most prevalent eating patterns of intermittent fasting which you can add to the diet include:
This fasting regimen involves restricting the daily eating periods to 8 hours or longer. One of the most popular examples of such a type of intermittent fasting is the 16/8 method. This fasting pattern features a window of 8 hours of eating, followed by 16 hours of fasting. During the 8-hour eating period, one is allowed to fit in 2 or more meals as per choice.
The proponents of the 16/8 method often claim it to be the most sustainable, convenient, and easy way to burn calories, shed extra kilos, and significantly improve health. Moreover, it also assists in combating high blood pressure and efficiently controlling blood sugar levels. You can repeat this fasting cycle as per your preference. It can range from once or twice every week or even every day.
The 16/8 regimen is more accessible to follow than other intermittent fasting routines. Moreover, it provides comparatively better results with nominal disruption to your lifestyle. The growing popularity of 16/8 fasting is due to its flexibility, fewer restrictive protocols, and ease of adoption into varying lifestyles. However, a few factors are essential to negate this method’s potential health risks. These include choosing a whole-food balanced diet and avoiding packaged food, sugary drinks, deep-fried items, & other ultra-processed foods.
Several studies have also associated drawbacks of this fasting technique which include:
Possibility of potential weight gain due to overeatingIncidence of physical symptomsHormonal alterations and effect on reproductive health
Studies have found that intermittent fasting may cause hormonal variations. Among females, this can impact menstrual cycles and, at times, fertility.
2. The 5:2 Diet
Also known as the Fast Diet, it ranks among one of the most preferred intermittent fasting regimens. Michael Mosley, a British journalist, initially popularised this diet form.
In this method, you need to follow five days of normal eating with two days of the restricted calorie intake of up to 500-600/day. A quarter of the standard calorie requirement is prescribed during these two days. The choice of the two days of limited diet in a particular week is as per the candidate’s preference, with at least a day of non-fasting. However, it is essential to note that, on days of non-fasting, the eating routine should be “normal” instead of consuming anything, especially junk or unhealthy food.
The 5:2 diet regimen showed benefits in line with other calorie restricting techniques. Moreover, studies conducted on the 5:2 diet and very similar alternate-day fasting routines like the 4:3 diet demonstrated several benefits, including:
Improvement in blood lipid levelsStudies have shown that this diet regimen effectively improves insulin sensitivity and ensures efficient control of insulin levels.Reduction in fat mass with no alteration in muscle massReduction of blood triglyceride levels by approximately 20%Better effectiveness on inflammation by reducing C-reactive protein (CRP) levelsAbout 40% reduction in leptin levels, a hormone secreted by fat cells that assist in regulating body weight.
3. Eat Stop Eat
The Eat Stop Eat intermittent fasting module has been gaining popularity recently. This fasting routine involves fasting for an entire day (24 hours) twice a week. Brad Pilon spoke about this method in his famous book ‘Eat Stop Eat.’ This form of intermittent fasting focuses more on the correlation between health and meal frequency & timing.
You need to fast for two days and then have a regular diet for the rest of the five days. However, a sensible decision of food choices and appropriate quantity consumption is ideal for the five days. In addition, you need to maintain optimum hydration levels while fasting. Also, you can consume calorie-free tea or coffee.
This practice also encourages weight loss through calorie deficit and metabolic shift processes. However, preliminary research also suggests that, during prolonged fasting, the process of metabolic shift may promote additional fat utilisation than conventional dieting strategies.
The fasting protocol implemented in the module is safe for most healthy adults. However, before adopting it, potential downsides should be considered, which include:
Insufficient intake of nutrientsHormonal alterationsSense of deprivation due to eating restrictions
4. Alternate Day Fasting
Another way of intermittent fasting is alternate-day fasting. In this, an individual fasts every other day and consumes anything the day after. All calorie-free beverages like water, tea, and unsweetened coffee are permitted. You can also consume 20-25% of the minimum energy requirement or roughly 500 calories. Studies have found that this modified approach is more sustainable and effective than conventional alternate-day fasting.
The benefits shown are similar to other forms, which include:
Reduction of risks associated with type 2 diabetesLowering risks of heart disease among obese individualsDecrease in LDL cholesterol levelsLowering of blood triglyceride levelImpact on autophagy, a process associated with degradation & recycling of old cells. This process plays a vital role in preventing neurodegeneration, cancer, heart disease, and other conditions.
Fasting promotes autophagy which plays a significant role in maintaining a healthy and long life. Although this fasting method looks promising, additional research on establishing a correlation between longevity is required further.
5. The Warrior Diet
This form of intermittent fasting involves short bursts of overeating, followed by a long duration of undereating. This method may lead to effective weight loss. However, it is often inappropriate as it leads to disordered eating. The genesis of this diet is from the eating patterns of ancient warriors, who feasted during the night after minimal food during the day.
Former Israeli Special Forces Ori Hofmekler first designed the warrior diet. Practitioners follow a 20-hour fasting period and consume healthy food during the leftover four-hour window.
The warrior diet yields similar benefits compared to other forms of intermittent fasting. However, it is more extreme than others. There is an absence of relevant research studies on this making it tough to follow perfectly.
Intermittent Fasting: Salient Points
Promising health outcomes and improving lifestyle are a few of the tempting promises made when you follow intermittent fasting. In addition, it is simple to implement. Fasting claims benefits by simply changing mealtimes. However, several dietitians ask you to exercise caution. A careful approach to intermittent fasting provides many potential benefits. Below are 10 points to keep in mind when starting with intermittent fasting.
1. Choosing the appropriate regimen according to one’s lifestyle
A few of the most popular modules include The Leangains Protocol, the 5/2 approach, and Eat Stop Eat module, and others.
The Leangains Protocol is one of the most widely followed fasting schedules worldwide. This fasting form is subdivided into several other types depending on the duration of fasting & non-fasting periods. However, the 16/8 method is considered one of the most popular regimens among all other calorie-restricting diets.
2. Controlling late-night eating episodes may prove to be highly beneficial
Eating right before bed causes indigestion, acid reflux, and circadian disruption, leading to discomfort & fatigue. Fasting in the morning followed by eating right before bedtime disrupts the circadian cycle. It promotes the occurrence of several ailments and also increases their severity. Conditions that can arise from eating a late meal at night include Type 2 Diabetes and various cardiovascular diseases. Moreover, eating late also messes with the body’s biological clock and may result in anxiety & depression.
3. Maintaining a controlled eating approach during non-fasting periods
Being mindful of food choices during non-fasting hours is extremely important for obtaining desired results from intermittent fasting. The quality of the meal is something you need to monitor.
Intermittent fasting should go hand in hand with a balanced diet. Nutritionists & dieticians recommend whole grains, lean protein, fibre-containing foods, and vegetables. In addition, you should include fruits with a low-glycemic index that do not spike up blood glucose levels. A stable blood sugar level is necessary as it helps avoid unnecessary cravings.
4. Maintaining a window of a minimum of 12-hours between meals
Depending on the size of the last consumed meal, 8 hours are required for the meal to be digested, absorbed & assimilated. However, in most cases, 8-hours is not enough for the body to complete these processes. Hence, professionals recommend at least a 12-hour window between meals for this detoxification process to sustain the system’s cleanliness.
5. Being aware of boundaries and restrictions
Individuals need to realise & be aware of the boundaries of intermittent fasting. Therefore, many should avoid such prolonged periods of fasting. For example, young adults, breastfeeding or pregnant women need to avoid fasting regimens as they have strict nutrient requirements.
Diabetic patients need to refrain from such fasting methods. They require regular insulin administration and are instructed on a strict diet of regular small meals at even intervals to avoid feeling dizzy or fatigued. Intermittent fasting among women can cause hormonal imbalance, affecting mood, fertility, and menstruation. Therefore, consulting professionals is advisable before such regimens.
6. Drink Plenty of Water
Drinking plenty of water: The body gets confused between feeling thirsty and hungry. Hence, the body needs ample hydration during intermittent fasting.
7. Add Healthy Fat
Please add two to three spoonfuls of healthy fats to the last meal to keep blood sugar levels steady during the fasting window.
8. Devising an appropriate workout routine
Exercising during a fasting diet is recommended by keeping certain factors in mind. Right exercises and the timing are some of them. For instance, exercising during a fasting state and early in the morning is advised by experts. A well-designed routine & workout schedule is also highly endorsed. People must be aware of the required exercises.
9. Listening to your body
It is necessary to listen to one’s body. Being mindful determines an individual’s health. For instance, symptoms like weakness or fatigue, irritation, anxiety, dizziness, and lack of concentration are usual at the outset of intermittent fasting. They indicate that the body is undernourished and starved. Hence keep a watch out and decide on modifying the fasting schedule accordingly.
It is natural for the body to react to the changes of fasting. Hence, experts recommend monitoring them and giving the diet schedule roughly a week to adjust to normalcy. However, suppose such symptoms persist for longer. Then, it is highly advisable to discontinue the diet and opt for other means to lose weight.
10. Maintaining the status of the journey
In intermittent fasting, a food journal plays an effective role in gauging progress, for instance, keeping track of the food consumed, symptoms, and emotions.
A few other pointers include playing around with different methods and breaking the fasting period steadily, regularly & uniformly. Also, it would help if you ate when the need arises. Finally, be gentle while commencing an eating plan and be aware of the difference between wanting to eat & needing to eat.
Benefits of Intermittent Fasting
The benefits of intermittent fasting are not limited to just weight loss. Several promising findings suggest that such time-restricted diets may offer several additional benefits.
1. Weight Loss and Control on Obesity
When the body gets used to alternate fasting & non-fasting periods, it consumes less, resulting in fewer calorie intake. Therefore, it is a primary factor for weight loss within intermittent fasting norms.
Moreover, it also facilitates weight loss by enhancing hormonal functions and promoting metabolic rates. Increments in metabolism positively control several hormone-induced insulin changes, norepinephrine, and HGH cholesterol. High metabolism rates burn additional calories and encourage weight loss.
A study on intermittent fasting demonstrated that it led to a highly appreciable 3-8% weight loss within 6-24 weeks. In addition, this research revealed loss of visceral fat where participants lose 4-7% of waist fat. Moreover, another study also highlighted that intermittent fasting results in lower loss of muscle mass than continuous calorie restricting diets.
2. Combating Type 2 Diabetes
According to the International Diabetes Federation (IDF), in 2021, globally, type 2 diabetes between 20 & 79 years stood at roughly 537 million. This number will reach 643 million and 783 million by 2030 and 2045. Also, the healthcare expenditure on diabetes was a staggering US$ 966 billion in 2021.
High blood sugar levels in diabetes result from increased insulin resistance. Therefore, any physical activity, fasting regimens, or food habits that reduce insulin resistance, assists in combating diabetes better. In addition, research says that intermittent fasting is highly beneficial to promote insulin resistance encouraging efficient reduction in blood sugar levels. For example, the prediabetes study demonstrated that intermittent fasting led to a 3-6% reduction in fasting blood sugar over 8-12 weeks.
3. Management of Heart Health
Hypertension is a common ailment affecting worldwide. According to a study in 2014, the prevalence of hypertension in rural & urban households in India stood at roughly 25% and 33%, respectively. In 2010, the problem ranked 3rd in entire South Asia. It is highly worrying as it indicates an abnormally high prevalence of cardiovascular diseases (CVD) and healthcare expenditure costs among Asian countries.
Animal studies on the effectiveness of intermittent fasting diets have demonstrated that it offers noticeable results in lowering blood pressure. A yearlong follow-up intermittent fasting study conducted by Buchinger Wilhelmi clinic in Germany on 1422 people showed outcomes similar to animal studies. Additional research on intermittent fasting suggests that it plays a pivotal role in lowering cholesterol and improving overall heart health.
Intermittent fasting significantly improves other risk factors associated with heart health, such as blood triglycerides, inflammatory markers, and LDL cholesterol levels. However, the majority of research was on animals. Therefore, the effects of intermittent fasting on humans need to be studied further before any recommendations.
4. Promoting Longevity
The ability of the intermittent fasting methods to positively contribute to a long life is perhaps one of its most exciting & researched outcomes. Furthermore, the impact of such a fasting regimen on health markers and metabolism suggests that it can play a substantial role in the same arena.
Studies on rodents found that both calorie-restricting diets led to long life. A 2017 study on mice concluded similar findings. During the experiment, they fasted alternatively. The results showed a whopping 13% increase in lifespan. Nonetheless, research studies on the effect of intermittent fasting on human lives’ longevity are pointedly understudied.
5. Increase in Cell Turnover
Intermittent fasting helps in the body’s detoxification by inducing autophagy. Autophagy is a lysosome-dependent regulated mechanism that removes damaged organelles, abnormal proteins, and other dysfunctional components. When the body goes through an intermittent fasting schedule, it initiates a process of healing and cleansing.
According to research on 11 participants, time-restricted feeding between 8 am to 2 pm only led to the expression of protein MTOR and autophagy gene LC3A. However, another study on mice verified that restriction of food intake led to a significant increase in neuronal autophagy specifically.
6. Reduced Inflammation and Protection Against Cancer
Several animal studies have demonstrated that calorie-restricting diets inclusive of intermittent fasting routines can lower inflammation levels. For example, a survey of 50 participants fasting for Ramadan involved eating at night and fasting between sunrise and sunset. They showed lower blood pressure, body fat, and pro-inflammatory markers during fasting hours.
Moreover, studies have also demonstrated that fasting every alternate day decreases the chances of lymphoma development, thereby reducing the risk of cancer.
The Final Word
Research studies demonstrate intermittent fasting is quite advantageous compared to many kinds of calorie-restricting diets. Additional benefits include protection against CVDs, amplification of brain functions, and better sleep patterns. It is vital to remember that intermittent fasting may have several potential side effects, but they vary within individuals. It can lead to insomnia, hunger, headaches, fatigue, and nausea. These possible side effects are temporary and generally settle down within a month. In addition, intermittent fasting assists in weight management. Finally, it helps address several chronic ailments like high cholesterol, irritable bowel syndrome (IBS), and arthritis.
However, intermittent fasting and other calorie-restricting diets are not suited for everyone. Experts always recommend consulting a primary care practitioner beforehand. A few groups of people who must avoid these fasting routines strictly include:
Teens & children under the age of 18Breastfeeding or pregnant womenIndividuals suffering from abnormal blood sugar levels or diabetesPeople with a history of eating disorders
Frequently Asked Questions (FAQs)
Q. How much weight can you lose in a month with intermittent fasting?
A. Intermittent fasting can lead to up to 2 to 6 kilos of weight loss in a single month if done in adherence to all protocols and mindfully. However, consider age, sex, stress level, and physical activity before choosing from the different intermittent fasting methods.
Q. How soon will I see results from intermittent fasting?
A. It takes approximately ten days to notice a difference in body structure. However, it may take roughly 2 to 10 weeks to lose significant weight. Generally, a week is usually required to lose a pound.
Q. Do I have to do intermittent fasting every day?
A. Since intermittent fasting can come in different forms, it would be wrong to conclude that all the methods are for daily practice. You can follow a few techniques every day but under the supervision of an expert. However, intermittent fasting, like The Warrior Diet, is not for every day.
The Leangains Protocol, especially the 16/8 method, is often considered the most sustainable, convenient, and easy way to burn calories, shed extra kilos, and improve health. This regimen features an 8-hour feeding window, followed by 16-hours of fasting. Compared to other intermittent fasting routines, the 16/8 regimen is easy and maintains a normal lifestyle. You can repeat this fasting and the non-fasting cycle as per your comfort. You can adjust the frequency from once or twice a week to every day. However, expert advice is of utmost importance before adopting the regimen.
Q. Can fasting bring on your period?
A. The impact of fasting and other diets on menstruation and overall reproductive health is minimal. Hence, whether fasting affects the menstruation cycle or not isn’t conclusive. However, studies say that diet restriction may impact the female reproductive organ. For example, the long duration of fasting affects the brain’s hypothalamus, which is responsible for regulating hormones like oestrogen, which in turn regulates menstruation. Similarly, studies have also confirmed that calorie restriction lowers the level of progesterone, which again reduces the chances of ovulation.
Q. Is 12 hours enough for intermittent fasting?
A. Researchers have found that subjecting the body to 10 to 16 hours of fasting transforms fat into energy. It releases ketones into the bloodstream and encourages weight loss. The 12-hour fasting period is suitable for beginners as it gives the body time to adjust to the new routine with ease. Once the body gets adapted to this, weight loss follows naturally.
Q. Does sleeping count as fasting?
A. Yes, while following intermittent fasting, sleeping is considered a fasting period. Therefore, one does not consume food or drinks during this state.
Q. What are the basic rules of intermittent fasting?
A. Intermittent fasting is a form of eating pattern where periods of eating and fasting are alternate according to a well-designed procedure. This fasting is to avoid any form of food or beverages containing calories strictly. One should eat a balanced, wholesome diet during the eating period and avoid unhealthy food. The most appropriate intermittent fasting method should be chosen and exactly followed. Few other basic rules of this form of fasting include:
Staying hydratedAvoiding sweetenersAvoiding late-night eatingKeeping a tab on day-to-day activities
A. It is necessary to be gentle with oneself. Therefore, maintaining a window of a minimum of 12-hours between meals is highly beneficial. Furthermore, since the duration of the fasting window is small, it is easier for beginners to adjust to such a routine with minimal difficulty. Moreover, including the sleeping period within these 12-hours is effective. Finally, maintaining at least a 12-hour window between meals ensures proper digestion, absorption, and assimilation. Therefore, professionals highly recommend this as it helps detoxify the body.
Q. Can I eat fruits during intermittent fasting?
A. Consumption of highly nutritious foods during the eating phase of intermittent fasting is highly encouraged. Since fruits contain high minerals, vitamins, fibres, and phytonutrients, these components play a crucial role in controlling cholesterol & blood glucose levels and maintaining a healthy bowel. However, it is also recommended to avail of fruits with a low-glycemic index, as these do not lead to a rapid increase in blood glucose level.
Q. Will a banana break a fast?
A. According to experts, bananas as a single food product are not recommended as a medium to break a fast. Also, bananas are more popular for their iron & sugar content rather than proteins or fats. Hence, combining bananas with other high-quality sources of proteins, fibres, and fat can break an intermittent fast. However, the consumption of bananas is encouraged before beginning the fasting phase since it digests significantly slower and provides a source of lasting energy.