Intermittent fasting, or IF for short, is a food-restricting approach that has been trendy for a decade now—which should give you an idea about how apparently influential it has been. Ever since it became popular back in 2012, millions and millions of people have tried intermittent fasting. Some of them hated it but many loved it and eventually adopted it not just as a way to lose weight but as a healthier lifestyle.
Intermittent fasting is, yet, not a modern approach at all. It is as old as history itself. Our ancestors have fasted for various reasons, most of them religious. Muslims fast every year during the Holy Month of Ramadan. For 30 days, food, drinks, and sex are restricted from sunrise to sunset but allowed from sunset to the sunrise of the next day. Christians, Jews, and people believing in many other religions fast as well.
That said, intermittent fasting as a diet appeared back in the 1940s. Over a series of experiments, researchers have restricted food for animals and they found out it helped them become more active and live healthier.
Then more than half a century later, intermittent fasting popped up again as a method of weight loss when British Journalist Michael Mosley examined the science behind fasting in a BBC2 documentary called Eat, Fast, and Live Longer. Mosley also wrote a book on the intermittent fasting approach called The Fast Diet.
Soon after the documentary and the book were released, intermittent fasting became trendy. Many people started trying it and found it helped them in many ways. From having more energy and becoming less stressed to sleeping better, and concentrating more.
Others also reported intermittent fasting helped them better schedule their days and stop the unnecessary weight gain by cutting out snacking. In addition, many people tweaked intermittent fasting to lose weight which we will explore later on, especially those who tried and failed to lose weight before.
Now a decade after and intermittent fasting is still trendy. So what is intermittent fasting, to begin with? What is it about it that is so good? How does intermittent fasting work?
Well, let’s find out.
What is intermittent fasting, to begin with?
Intermittent fasting is pretty aptly named. It is ceasing food consumption for a period of time. Physiologically speaking, intermittent fasting is a hormonal approach that changes the levels of some important hormones in the body, giving them a chance to work more efficiently for the sake of a healthy body.
Though many people use it as a way to lose weight, intermittent fasting is not a diet. It does not have anything to do with what you eat but rather with when you eat it.
With intermittent fasting, every day is divided into two periods of time: the fasting window and the eating window. In the fasting window, one is not allowed to eat or drink anything except for water, plain black coffee, sugarless tea, or any other kind of beverages that have absolutely no calories. Once the fasting window comes to an end, one can eat.
The most popular and effective intermittent fasting style is the 16:8 which includes fasting for 16 hours with an eight-hour eating window. That said, there are many other styles of intermittent fasting that should suit different people. There is the 12:12 fast and the 14:10 fast, which are both good for IF beginners.
There is also the 18:6 fast, the 20:4 fast, and the OMAD (one meal a day) in which a person fasts for 23 hours and has one hour to eat only one meal. Sleep hours are definitely included during the fasting window, which makes the whole intermittent fasting experience less difficult.
Interestingly, because intermittent fasting inevitably incorporates hunger, some people like to call it a short-term starvation period!
On the other hand, some intermittent fasting masters take the daring action of fasting for 30 hours and sometimes even 36 hours! That definitely is not suitable for everyone, if not most people. Fasting for such long hours can result in disastrous side effects, the least dangerous of which include very low blood pressure, dizziness, irritability, and harsh mood swings—we will get to the side effects of intermittent fasting in a bit.
How does intermittent fasting work?
So this is what people do on the outside when intermittently fasting. In order to understand how intermittent fasting works on the inside, contributes to weight loss, and improves overall health, we need to review some biology basics.
Since food is our number one asset for growth, there are a lot of processes that happen in our bodies to make the best out of the food intake and enable functioning in the most efficitent way possible. Such processes are regulated by hormones.
Hormones are chemicals produced by different parts of the body. You can think of them as messengers. They travel through the bloodstream toward specific organs and cells and instruct them to do certain functions.
Some of the most important hormones in the human body, at least those related to intermittent fasting, are:
- The human growth hormone: hGH or somatotropin
- The hunger hormone: ghrelin
- The fullness hormone: leptin
- The insulin hormone
The human growth hormone (hGH) is produced by the pituitary gland in the brain. It is responsible for promoting the growth of bones and organs. When it is released, it tells the cells to multiply and therefore grow. In addition, the growth hormone activates metabolism in the body which converts food into blood sugar or glucose. Glucose is what gives us the necessary energy to function.
So we can say that the growth hormone is what gives the body energy in the form of glucose. If the glucose level is already high; meaning the body has got energy, the growth hormone will not be released.
The opposite is also true. When the blood sugar is low, the growth hormone is released to activate metabolism and get energy. During fasting, there is no food intake; there is no food to burn. So the body will turn to the stored fat and burn it to produce energy. In addition, the release of the growth hormone helps the body function more properly and improves brain function.
In short, intermittent fasting reduces blood sugar levels, which releases the growth hormone to activate metabolism and burn stored fats. Therefore, intermittent fasting assists in weight loss.
(2) Ghrelin and leptin
These two are the hunger and fullness hormones, respectively.
Ghrelin is mainly produced by the stomach when it is empty. It tells the brain to increase appetite and that it is time to eat. So the ghrelin level is usually very high before eating. When we eat, ghrelin is decreased and leptin, the fullness hormone, is released. It tells the brain that the body is no longer hungry and to stop eating.
The higher the ghrelin levels are, the more likely we are to eat. When ghrelin gets high in a moderate way, we get to eat moderately too. However, when it is high more frequently, we consume more food which leads to weight gain. Even worse than that, it makes weight loss more difficult since one’s appetite becomes uncontrollably increased.
Foods high in fructose corn syrup such as soft drinks, fast food, sweets, and canned fruits in addition to sugar and salt increase ghrelin. On the other hand, food rich in protein like beans, chicken, and fish and healthy carbs such as whole grains, fruits, and vegetables moderate, if not reduce, ghrelin levels.
When ghrelin is kept at a moderate or low level, the leptin level gets high, making us feel full for a longer period. Therefore, we do not consume as much food. So glucose levels stay low, pushing the growth hormone to be released and more body fat to be burnt.
Interestingly, intermittent fasting regulates ghrelin levels. It stops them from getting high and stabilises leptin levels to help us feel full. So again, intermittent fasting increases the chance of weight loss or at least prevents weight gain.
As we have just mentioned, when we eat food, the growth hormone is released to activate metabolism. Metabolism turns the food into glucose, or blood sugar, which we need to have energy and function.
When we eat too much, drink too little water, or do not exercise at all, the glucose level gets too high. High blood sugar can lead to permanent damage in the eyes and hand and feet nerves. It increases the risk for strokes in addition to heart and kidney problems. High blood sugar is literally life-threatening.
That said, we are blessed to have a guardian angel in our bodies and that is the pancreas. Once we consume food, the pancreas releases the insulin hormone which rushes to moderate the glucose levels in the blood.
Insulin retains a certain amount of glucose in the blood that keeps the body safe and functioning. Then, it takes the excess glucose, bulks some of it to become glycogen, and stores it in the liver and muscles for later use—glycogen is, therefore, a complex form of glucose molecules.
Interestingly, the liver, all the body muscles, as well as every other place where glycogen is stored can collectively hold a maximum of 600 grams of glycogen. When there is still more glucose to store but there is no room for it, the body turns this excess glucose into fat and stores it in the body cells such as those in the belly, chest, and hips.
In other words, every time we overeat, especially meals that are high in carbohydrates, or when we snacks all day, the glucose level gets too high. The body will only take what is necessarily enough for it to function properly and store glycogen as an energy boost backup. The remaining glucose, which can still be too much, is stored as fat. That is why we put on weight on a high-carb diet or when we overeat in general.
Furthermore, snacking all day does have other more serious drawbacks than being overweight.
Eating more frequently on a daily basis leads the pancreas to release insulin more often. Gradually, the body cells become unable to respond to insulin. Think of it as if they refuse to open their doors and receive glucose because insulin keeps knocking repeatedly.
This case of cells not responding to insulin is called insulin resistance. When cells do not take the excess glucose, it is sent back to the blood. Over time, the consistent high glucose level leads to obesity and type 2 diabetes.
All in all, intermittent fasting works like this:
- Food is restricted, glucose gets low, ghrelin levels are regulated, and appetite is controlled.
- Glucose is low, growth hormone is released, metabolism is activated, and fat is burnt.
- Glucose is low, insulin is not released, no fat is stored, and more fat is burnt.
Benefits of intermittent fasting
As we have just explained, intermittent fasting as it restricts food intake leads to several benefits related to activating metabolism, ceasing fat storage, and allowing more fat burn.
Secondly, intermittent fasting leads to less food consumption and more moderate eating. It helps manage appetite, makes you feel less hungry and more full, and assists in getting rid of bad eating habits such as binge eating and frequent snacking. As a result, it reduces bloating and slugginess.
Thirdly, intermittent fasting either protects from or helps with diabetes. Low blood sugar levels also keep insulin at a low level. In return, less and less fat is stored, preventing weight gain.
Intermittent fasting when combined with consistent exercise helps not just reduce but reverse insulin resistance. This lowers the risk of getting type 2 diabetes. Besides, it lowers the glucose levels in individuals with diabetes, allowing them to live a better life.
Other research-proven benefits of intermittent fasting include:
- Improving heart health and blood vessel functions.
- Improving memory and concentration.
- Reducing chronic pain intensity.
- Reducing side effects of chemotherapy.
- Reducing the risk of cancer.
That said, it is highly recommended to consult a nutritionist or a healthcare professional before attempting intermittent fasting, especially for diabetic people and those with a history of eating disorders.
Side effects of intermittent fasting
In spite of everything we just said, intermittent fasting might still not be suitable for everyone. Even those who do not have any medical conditions which might lead to unpleasant consequences when fasting might not be ‘OK’ with such prolonged hunger. And that is totally fine.
For instance, one YouTuber who tried intermittent fasting for 30 days clearly stated that he was not happy with the experience despite losing a few pounds already. He said it interfered with his personal and social life. He was unable to schedule his work, his exercise routine, and his after-work social activities with his 16:8 intermittent fasting plan.
Furthermore, intermittent fasting can have unpleasant side effects if done by:
- Pregnant women
- Nursing mothers
- People with anemia
- Anyone with poor metabolism
Common intermittent fasting mistakes
For some people, intermittent fasting works like a miracle. Speaking from my own personal experience at least, I pretty much feel active, light, and generally energetic.
I am also more appreciative of getting rid of bloating which was super uncomfortable and rather irritating before.
In addition, I feel I have more head space to focus on the important things, not having to think about food nor being controlled by my false hunger and increased appetite and cravings all day long.
So when people experience similar benefits of intermittent fasting, they cannot help but want more of them, especially those related to weight loss.
That leads them to overdo intermittent fasting. That, in turn, results in some mistakes that can potentially lead to serious consequences. In this section, we are going to explore some of the common mistakes people make when doing intermittent fasting.
(1) Fasting, but still eating a lot
People mistakenly think that just because they do not eat for a long time enables them to eat whatever they want. Ironically though, they still expect themselves to lose weight. This is probably coming from the notion that fasting inevitably forces their bodies to burn fat and therefore lose weight. While this is generally true, it is not as simple as it sounds.
During fasting, there is no food intake so the glucose level, our energy driver, gets low. On the first few days of fasting, we might feel dizzy, lightheaded, and weak. To prevent that, our superhero pancreas shows up again and releases another hormone called glucagon.
Simply put, glucagon reverses the insulin work. It takes the glycogen from the liver and muscles and turns it back into glucose. Then it pushes it into the bloodstream to give energy to the body. When the glycogen storage is over, the body will turn to the stored fat and burn it for energy.
So, when some people naively think they are allowed to eat whatever they want since they fast for 16 or 18 hours, they are in fact encouraging weight gain. That is because by eating too much, they are constantly refilling their glycogen stores, which the body consumes first for energy. And as long as there is enough glycogen in their liver and muscles, it will be absolutely unnecessary for the body to burn any of the stored fat.
The point is to run out of the glycogen store quickly so that the body fat is used for energy and thus burnt. That is why people who follow a low-carb diet while intermittent fasting are much more likely to lose weight since they are reducing the glycogen stores and allowing more fat burn.
Moreover, fasting for 8 or 10 hours does not really help much with fat burn and weight loss either since the body does not get enough of a chance to use all the stored glycogen. Fasting for longer hours guarantees the body uses all the glycogen and then turns to fat burn for energy. In this matter, a 16:8 intermittent fasting plan was found to be pretty efficient.
(2) Fasting more often, fasting too long
While a 16:8 fast is considered the most efficient plan, some people try to push their fast a little longer to 18, 20, or sometimes even 24 hours. That might be OK for several individuals, maybe a little or a lot challenging for others; yet, it is doable after getting used to hunger.
But some people take it to the extreme by fasting longer than 24 hours, seeking more and faster weight loss or whatever other benefit they are on the lookout for. However counterintuitive this might sound, fasting for too long, in fact, reduces weight loss. Here is how this happens.
When there is no calorie intake, the body burns glycogen and then fat to get energy as we have just explained. However, once the body realises this fast is apparently prolonged, it slows down metabolism, entering what is known as starvation mode.
During starvation, the body limits calorie burn to conserve energy. Since fat is the only source of energy left, it burns less and less of it to keep the body alive and functioning as long as possible. As a result, people do not lose as much weight, if not any, during such very long fasting windows.
Besides not losing weight, starvation mode leads to:
- Low body temperature (feeling cold)
- Poor concentration
- Low blood pressure
- Mood swings
Starvation also increases food cravings. These can lead to a subsequent, uncontrolled behaviour toward food such as emotional eating or binge eating. Besides obesity, such eating disorders can have several other serious consequences such as developing a negative body image, boredom, self-loathing, stress, and depression.
On some extreme levels, some individuals might try to force themselves to throw up the food they ate or starve themselves afterwards in a way to reverse the events.
In addition, when people who have fasted for too long consume food, most of it is stored as fat. In this manner, the body is taking precautions in case it goes through starvation again in the future. Consequently, little to no weight is lost. Weight gain becomes even more likely.
(3) Fasting, but eating too little
Another common mistake that many people make is lowering their calorie intake to a drastic level during the eating window. This way, they think they are optimising their fast so they can achieve better and faster results.
But just like eating too much leads to fat storage, eating too little also, surprisingly, stops weight loss and can potentially lead to weight gain.
When we eat less during our eating window, we work on keeping the blood sugar level low and therefore reduce the insulin release so the body can turn to fat for energy. But when we eat too little too often, the body will soon realise it is not getting enough fuel, it will turn on starvation mode.
And like what happens when fasting for too long, the body will slow down metabolism and store all the already-little calories it gets to make up for the upcoming days of this extended starvation.
In addition, consuming very few calories keeps the blood sugar level constantly low which results in:
- Hair loss
- Blurred vision
(4) Not sleeping well
We always hear that sleep is super important. Most of the reasons why this is the case are associated with feeling active, being able to concentrate, study or work better, etc. And this is absolutely true. Do we not feel lethargic, sleepy, and unable to focus when we are sleep-deprived?
Yet, it may sound surprising for some that poor sleep has a negative effect on weight loss. In other words, if you do not sleep well, you are less likely to lose weight. That is because the lack of sleep decreases the level of the leptin hormone and increases that of ghrelin. As a result, appetite and hunger increase. Consequently, we are prone to eat unhealthily or even binge-eat.
During sleep, the growth hormone level increases. And we have understood earlier how important this hormone is for our overall body health and for weight loss in particular. So if we cannot fall asleep, sleep poorly, or wake up multiple times at night, growth hormone levels are altered. As a result, our health gets badly affected and weight loss becomes difficult.
Another point about sleep is when we sleep. God created our bodies to be awake during the day and sleep at night. Sleeping at night allows the body to repair, improves brain function, and regulate its internal biological clock. While sleeping during the day is fine, it is not as efficient as having a good night’s sleep which is absolutely necessary for good physical and mental health.
(5) Not drinking enough water
Adults need to drink 2-3 litres of water on a daily basis. Water regulates body temperature, normalises blood pressure, helps with digestion, takes nutrients to the cells, and improves skin health.
On the other hand, not drinking enough can lead to dehydration. Since there is not enough water to normalise the internal temperature, the body becomes vulnerable to overheating. This is a condition called heat exhaustion which causes heavy sweating, making the body lose even more water. Individuals with heat exhaustion also experience fast breathing, rapid heartbeat, pale skin, dizziness, tiredness, and headaches.
Besides these negative effects, dehydration can potentially lead to poor kidney function, which may develop kidney stones. In some cases, prolonged dehydration can even cause kidney failure.
Dehydration may also cause sleeplessness which, as we explained a few paragraphs ago, has several negative physical and mental effects too.
Even more than that, dehydration can lead to weight gain. Since the amount of water in the blood is low, glucose gets more concentrated, causing insulin to be released to regulate it. And insulin leads to fat storage and weight gain.
How to start intermittent fasting
Whether or not you want to lose weight by doing intermittent fasting, it is still a good approach to improve your overall health, regulate body hormones, protect yourself against potential diseases, and become more active, focused, and feeling generally good.
So if you are still reading, I will assume you are interested in starting or at least trying intermittent fasting. In this section, I will demonstrate some progressive steps to help you start intermittent fasting. But before this, there are a couple of points I need to clarify.
It is always a good idea to consult a nutritionist first before doing intermittent fasting. They will be able to assess your overall health conditions and may even ask you to get some tests to check your body hormone levels and whether or not you have insulin resistance.
Secondly, always keep in mind that the point of doing intermittent fasting is to improve the body’s health so avoid taking things to the extreme or going too hard on yourself. Your body is systematised to your current lifestyle and eating habits. Going too far from the beginning will definitely shock the body and may even cause it to collapse.
What I mean by ‘too far’ is, for instance, doing 16:8 fast, following a low carb or a keto diet, and exercising for hours every day while a few days ago you were binge-eating on your living room couch while binge-watching Netflix!
Are we clear now? Let’s move on.
(1) Stop snacking
If you are into intermittent fasting, but still feel reluctant to feel hungry for a long period of time, you can start by stopping snacking between your meals. Based on everything I have explained so far, which I hope made sense to you, snacking manipulates insulin, encourages fat storage and weight gain, and risks getting insulin resistance.
So do your best to avoid that cookie an hour after you had your breakfast already or that midday maple cream latte, thinking that it will give you a boost of energy and sweetness.
You may combine your snacks with your meals if you want, but just make sure you have no calorie intake between your meals. That said, you can use zero-calorie beverages such as sugarless tea and black coffee. Also, make sure you eat only three meals throughout the day. This will gradually train you to stay for a period of time without snacking.
That is fasting in between meals. It is ‘intermittent’ fasting after all.
(2) Do the 12:12 fast
Now that you trained a little bit on having your meals and only your meals during the day, try to combine all of them in a 12-hour window. Whether you have breakfast early in the morning or skip it completely to lunch, just set your timer to 12 hours once you eat your first meal of the day.
Once your timer goes off, do not get anything into your system. Though you might feel that not eating for 12 hours is too long and rather self-sabotaging, you can make it easier by including sleep during your fasting window.
So if you finish your dinner by 9:00 in the evening and you go to bed by 11:00, consider eight hours of sleep. Then, after you wake up, wait a couple of more hours before you have your breakfast. And your fast s complete.
(3) Fast at the same time, every time
This is another trick that can get you through your fasting window with less difficulty.
Try to start and end your fast at the same time every day. While there is nothing wrong with having a different schedule every time you fast, it is way recommended you follow the same timing. This helps regulate your ghrelin level so the hormone is released only at that same time prior to eating. In other words, you manipulate your body not to feel hungry all day long.
(4) Enlarge your fasting window gradually
Once you are more used to your 12-hour fasting window in which hunger is bearable and even almost ignored, start widening your fasting window a little bit. Still, avoid jumping to a 16:8 fasting plan when you are only used to a 12-hour fasting plan. You can go on a 13:11 fast for a couple of days. If everything is ok, move it up to 14 hours, and so on.
Research shows that the insulin level drops significantly after at least 14 hours of fasting. So getting your fasting window to 16 hours and 18 hours gives you a lot more benefits. But again, make sure you do this pretty gradually to avoid any counter-reactions such as overeating or binge eating.
(5) Cut down on carbs
No one does intermittent fasting for the sake of starving themselves. Everyone is seeking at least one benefit from the experience. And the number one benefit that intermittent fasting offers is reducing insulin and improving overall health by releasing the growth hormone.
That is why people who do intermittent fasting are advised to eat a low-carb diet during their eating window. Come to think of it, if you starve yourself for 16 hours and successfully drop your insulin level significantly, eating high-carb meals will spike it again. And by now we know what happens when there is too much glucose in the blood.
So cutting down on carbs is a way to make your fast pay off and give you whatever benefit you are seeking out of the whole experience.
That is why your very first meal after your fast ends is much more important than you think. In short, you need to avoid breaking your fast with carbs. Examples of this include bread, grains (yes, overnight oatmeal is a no-no), sweets of any kind, breakfast cereal, pancakes, waffles, fruits, etc. You also need to avoid combining protein and carbs like when eating burgers and pizzas.
Such foods that spike insulin are called hyperinsulinemic foods which you should avoid at all costs.
Another thing about carbohydrate-rich fast breakers is that they encourage overeating. The reason is that carbs are digested incredibly quickly. Besides spiking insulin as we explained, they do not provide a feeling of fullness for long. Soon enough after breaking your fast with carbs, you will feel hungry and may eat again.
The point of consuming less carbs is to shift your body from being glucose-adapted to being fat-adapted. That means you push your body to burn fat for energy instead of depending on glucose which directly translates to carb consumption. Fasting for at least 16 helps make this shift. Yet, it does take a while to sink in so go easy on yourself and give your body the time to go at its own pace.
To help make this shift also, you should break your fast with foods that release low levels of insulin such as those rich in protein and healthy fats.
Interestingly, healthy fats have absolutely no effect on blood sugar and therefore on the release of insulin. On the other hand, protein does provoke insulin but the glucagon hormone is also released along with it. If you remember from what we demonstrated earlier, glucagon is the opposite of insulin. So, whatever insulin does is undone by glucagon.
In other words, breaking your fast with a combination of protein and healthy fats maintains the low level of blood sugar and the low insulin level achieved during your fast.
Examples of good fast breakers include:
- Eggs and cheese
- Greek yoghurt
- A handful of nuts
- Tuna and salad
- Chicken breasts
So far, we explored some breaking fast dos and don’ts. But what about the meals?
Well, whatever the length of your eating window is, it is always recommended you eat two meals: the first is the one you break your fast with and the second should go prior to starting your next fast. And of course, no snacking is allowed.
For me, I like to have a small fast breaker and two meals. When I learned about intermittent fasting and how properly I should eat, I knew that I would follow the rules to get my desired results. At the same time, I was not quite OK with eating plain protein and fats for my first meal so I made a compromise.
After I consulted my nutritionist, I made up my mind to have a teeny-tiny meal high in protein and fats to break my fast with. This is usually a handful of nuts (about 25-30 g), a cup of full-fat Greek yoghurt, a boiled egg with some cheese and a drizzle of virgin olive oil. Then after an hour or two, I eat my first nutritious low-carb meal. Then I eat my second, still low-carb, high-protein meal by the end of my eating window.
OK. Now to the long-awaited point: working out while doing intermittent fasting.
We have always been told that we need to eat something prior to a workout especially if it is a strength training or cardio session. An apple, a banana, or a granola bar make some good pre-workout snacks that many people consume to get energy.
In addition, coaches and nutritionists highly recommend we eat a high-protein meal after a workout to help repair the muscles. So how exactly can we best fit exercise time with intermittent fasting?
Before we move on, we just need to clarify the reason behind working out. Is it just for building muscle and improving overall body health and endurance? Or do you seek to shed some weight out of it?
If fat burn is the aim, taking a high-carb snack such as a granola bar will just raise the glucose level. As a result, all the energy used during the workout will come from that glucose and no fat will be burnt.
On the other hand, working out while fasting leaves the body with the fat store as the main energy source and therefore it burns fat.
Thus, you would better schedule your workouts at the end of your fasting window. If you are doing a 16:8 fast or fasting for long hours, it is guaranteed that your body will burn since it will have run out of its glycogen stores already. As a result, your body will turn to the stored fats for fuel which leads to weight loss.
A study has also found that exercising while fasting can increase the fat burning rate from 9 and up to 24 hours after your exercise. That means you will continue to burn fat even after you break your fast.
So in short, it is much recommended you work out during, especially prior to the end of, your fat, to encourage more weight loss.
However, I must mention here that such a thing might not be bearable at the beginning of your intermittent fasting experience. During these days, your body is dealing with hunger and cravings. It is trying to regulate the hormones to get to the correct healthy levels.
So trying to work out during your fast at first might make you feel lightheaded or that you are going to pass out. So again, take it gradually. You either go light on the exercise during your fast and immediately stop if you feel dizzy. Or you may work out during your eating window and once you feel strong during your overall fasting window, you can shift your workouts there.
If you were used to working out after a meal or after consuming an energy-boosting snack, there is no way for you to work out on a 16-hour-long empty stomach and not get harsh consequences. So again, take it gradually. First off, work out at the beginning of your fasting window, around four to five hours before your last meal. Then increase the period between your last meal and the workout until you are able to get your routine done towards the end of your fasting period.
Another benefit of working out during your fast is helping get rid of insulin resistance since the fat burn rate is highly increased during and even for a prolonged period after the workout.
This also helps with the necessary need to eat after a workout. Working out near the end of your fasting window allows you to make the best of your first meal, forcing you to eat it clean (no added carbs as we explained earlier) by focusing on muscle-building protein.
Last but not least
Intermittent fasting is a result-proven approach to developing better eating habits, losing weight, and improving insulin resistance in addition to many other benefits. However, it is not obligatory at all. People should surely prioritise their health but they still need to listen to their bodies. Forcing the body to go far beyond its capabilities can potentially lead to serious consequences.
Intermittent fasting, as we have seen, is all about reducing the insulin levels too much which is directly associated with reducing blood sugar. However, if you feel your blood sugar is getting too low that you are about to faint, break your fast immediately.
The opposite is also true. If your fast is coming to an end but you still feel quite active and focused, you can continue fasting for a couple of more hours. Just because the timer goes off while you are still feeling good does not mean you should eat. Remember that fasting longer than 16 hours drives more benefits.
A final point is, again, to always consult a nutritionist before trying intermittent fasting. Based on your health condition, they will be able to advise you on the best way to apply this approach in order to avoid mistakes as well as any unpleasant outcomes.