Intermittent fasting has become one of today’s most popular health and fitness trends. It is being used by many people to achieve weight loss, improve their health, and simplify their lifestyles.
Several studies have shown its powerful effects on the body and brain as well as its benefits for longevity.
In this article, we will explain intermittent fasting in depth.
What Is Intermittent Fasting?
Intermittent fasting is more of an eating pattern—not a diet—that cycles between fasting and eating periods. You don’t usually specify which foods to eat but rather when you should eat them.
There are various intermittent fasting methods but the most common ones involve fasting for 16 hours daily or fasting for 24 hours twice every week.
Throughout human evolution, fasting has always been the practice. Ancient hunter gatherers couldn’t find anything to eat; they didn’t have refrigerators, supermarkets, or food available year-round. With that, humans are able to function even without food for extended periods of time. In fact, it is even more natural to fast from time to time than always eat more than 3 meals a day.
Moreover, fasting is also often done for religious or spiritual purposes because some religions, such as Christianity, Buddhism, Islam, and Judaism, mandate some form of fasting.
How to Intermittent Fasting?
There are different methods to do intermittent fasting. All involve splitting the day or week into periods of eating and fasting. During the period of fasting, it’s either you eat very little or you eat nothing at all.
So below are the most popular methods of doing intermittent fasting.
The 16/8 method
The 16/8 method, which was popularized by fitness expert Martin Berkhan, involves a daily 16-hour fasting and a strict 8-hour eating window. During your eating window, you can have over two meals.
Also known as the Leangains protocol, this method of fasting can be as simple as not eating anything after dinner until lunch the following day.
For instance, if you finished eating your dinner at 8 p.m. and skip your breakfast the next day, you’re technically doing a 16-hour fast.
Generally, women are recommended to only fast for 14 to 15 hours as they seem to do better with shorter periods of fasting.
This method may be hard to get used to at first for people who are used to eating breakfast every morning.
Within the fasting period, you can drink water and other zero-calorie beverages like coffee and tea to help reduce feelings of hunger. But during your eating window, it is highly important that you primarily eat healthy foods. You won’t be able see the effect if you eat an excessive number of calories or junk foods.
The 5:2 diet
The 5:2 diet involves restricting your calorie intake to 500 (for women) and 600 (for men) for 2 days while eating normally for 5 days. Popularized by British journalist Michael Mosley, this diet is also known as the Fast Diet.
For instance, you can eat normally every day of the week except Tuesdays and Fridays. During those days, women are recommended to eat 2 small meals of 250 calories each and men can take 300 calories each.
Although there are a number of studies as to the potential benefits of intermittent fasting, there are no studies conducted on the 5:2 diet itself.
Eat stop eat
Popularized by fitness expert Brad Pilon, this method involves fasting for 24 hours once or twice every week. This has been quite popular for a few years.
This method amounts to a full 24-hour fast, e.g., you fast from breakfast one day to breakfast the next day. You can also fast from lunch to lunch or dinner to dinner—it gives you the same result.
No solid foods are allowed but zero-calorie beverages like water and coffee are permitted.
If your goal is to achieve weight loss, it’s highly important that you normally eat during the eating windows. You have to consume the same amount of food like you hadn’t been fasting at all.
Many people may find this full 24-hour fast unsustainable; however, you need not go all in right away. You can start fasting for 14–16 hours, then level up to 24 hours. In other words, you can do it slowly.
Alternate-day fasting
Alternate-day fasting involves fasting every other day. This method has different versions: some permit calorie intake of 500 during the fasting periods.
Many test-tube studies demonstrating the health benefits of this eating pattern used some version of alternate-day fasting.
However, this is not recommended for beginners because a full fast every other day is considered extreme. Going to bed hungry two to three times a week is not very pleasant, making this method probably unsustainable in the long run.
The warrior diet
Popularized by fitness expert Ori Hofmekler, the warrior diet involves consuming small amounts of vegetables and raw fruits during the day and having one huge meal at night. This is one of the first well-known diets to include a form of intermittent fasting.
In this method, you basically fast all day and feast at night within a 4-hour eating window. Its food choices mostly include whole, unprocessed foods—quite similar to that of the paleo diet.
Spontaneous meal skipping
You really need not follow a structured IF plan to experience some of its potential health benefits. You can simply skip meals when you are too busy to cook and eat or when you just don’t feel hungry.
Your body is well equipped to handle extended periods of hunger, let alone not eating a meal or two from time to time. It’s a myth that we really need to eat every after a few hours so as not to starve or lose muscle.
So if you’re not really hungry, you can skip breakfast and just eat a filling and nutritious lunch and dinner. Or if you’re travelling and don’t have something to eat, you can do a short fast.
You’re basically doing a spontaneous intermittent fast when you skip a meal or two when you feel inclined to do so. Just make sure that you eat filling and healthy foods during the other meals.
How Does Intermittent Fasting Affect Your Cells and Hormones?
Several things can happen on the cellular and molecular level of your body when you fast. For instance, in order to make stored fat more accessible, your body adjusts hormone levels. Your cells perform necessary repair processes and change the expression of genes.
Human Growth Hormone. When you fast, your growth hormone levels rise as much as 5-fold. This results in fast loss and muscle gain.
Insulin. Your insulin levels drop dramatically and your insulin sensitivity improves when you fast. Your stored body fat becomes more accessible when you have lower insulin levels.
Cellular repair. Your cells perform cellular repair processes when fasted, including autophagy—your body’s way of cleaning out old, dysfunctional proteins that build up inside cells in order to regenerate newer and healthier cells.
Gene expression. Fasting also allows changes in the gene function that is related to protection against disease and longevity.
These changes are responsible for the health benefits of intermittent fasting.
Intermittent Fasting for Weight Loss
The most common reason for people to do intermittent fasting is to achieve weight loss.
Intermittent fasting makes you eat fewer meals, leading to an automatic reduction in calorie intake. In addition, it changes hormone levels which can be beneficial for weight loss.
Aside from increasing growth hormone and lowering insulin levels, intermittent fasting also increases the release of norepinephrine (noradrenaline)—a fat-burning hormone.
This eating pattern is an effective weight loss tool because it helps you eat fewer and burn more calories, which then changes both sides of the calorie equation.
Intermittent fasting research for weight loss
A review study published in 2014 showed that intermittent fasting can result in 3–8% weight loss in just over 3–24 weeks. This is a significant amount as compared with most weight loss studies. In the same study, people also experienced a 4–7% reduction of their waist circumference, which shows a significant loss of harmful belly fats that can build up around your organs and lead to diseases.
Another study also found that this eating pattern can cause lesser muscle loss as compared with the standard method of continuous calorie restriction.
However, it is noteworthy that the main reason for its success is the fact that this eating pattern helps you eat fewer calories. Thus, you may not experience its benefits for weight loss if you binge and eat massive amounts during your eating periods.
Intermittent Fasting Benefits and Side Effects
Intermittent fasting benefits
Several animal and human studies have been conducted on intermittent fasting. These studies have demonstrated that this eating pattern can have potential benefits not only for weight control but also for the health of your body and brain. In fact, it has been shown to have benefits for longevity.
Aside from weight loss, here are other potential health benefits of intermittent fasting.
It reduces insulin resistance, which also reduces your risk of developing type 2 diabetes.
Type 2 diabetes is characterized by high levels of blood sugar in the context of insulin resistance. Thus, anything that helps reduce insulin resistance should protect against type 2 diabetes.
Intermittent fasting has been found to help improve insulin resistance which results in an impressive reduction in blood sugar levels.
Human studies on intermittent fasting found a 3–6% reduction on fasting blood sugar while 20–31% reduction on fasting insulin.
An animal study in diabetic rats found that this eating pattern has protection against kidney damage, which is one of the most severe diabetes complications.
However, the effects may vary by gender. A study in women found that blood sugar control worsened after doing intermittent fasting for 22 days.
It reduces inflammation and oxidative stress.
Oxidative stress, which is an imbalance of antioxidants and free radicals in the body, plays a key role in the aging process as well as in many chronic diseases. The unstable molecules called free radicals react with and damage other essential molecules, including DNA and protein.
Some studies have demonstrated intermittent fasting to help improve the body’s resistance to oxidative stress.
Moreover, studies have shown that this eating pattern can help fight inflammation—another key factor for all sorts of common diseases.
It has potential benefits for heart health.
Studies have shown that intermittent fasting can help improve a number of risk factors, including blood triglycerides, blood triglycerides, blood pressure, blood sugar levels, and inflammatory markers.
However, these studies are mostly conducted on animals. Further human studies are needed to fully elucidate the effects of intermittent fasting on human heart health.
It induces various cellular repair processes.
When fasted, the cells in the body initiate autophagy—a cellular waste removal process. During this process, the cells break down and metabolize dysfunctional proteins that accumulate inside cells over time.
Increased autophagy may help protect you against several diseases, including Alzheimer’s disease and cancer.
It can potentially help in cancer prevention.
Cancer is characterized by uncontrolled cell growth, making it a terrible disease.
Fasting was shown to have potential benefits on metabolism that may result in reduced risk of cancer.
Promising evidence from animal studies shows that this eating pattern may help in cancer prevention. Some evidence also showed that fasting reduced various side effects of chemotherapy for human cancer patients. However, further human studies are necessary before making a recommendation.
It is beneficial for the brain.
Something that is beneficial for the body is often beneficial for the brain as well.
Intermittent fasting helps improve various metabolic features that are essential for brain health, including reduced insulin resistance and blood sugar levels, reduced inflammation, and reduced oxidative stress.
Some studies in rats have found that this eating pattern may help increase the growth of new nerve cells, which can be beneficial for brain function.
Animal studies have also demonstrated that it can help protect against brain damage due to strokes.
It can potentially help prevent Alzheimer’s disease.
Alzheimer’s disease is one of the most common neurodegenerative diseases worldwide. Since no cure is available for this disease, it is highly important to prevent it from showing up in the first place.
A study in rats found that intermittent fasting may reduce the severity or delay the onset of Alzheimer’s disease.
A series of case reports demonstrated that daily short-term fasts were able to help improve Alzheimer’s symptoms in 9 out of 10 patients.
Some animal studies also found that fasting may potentially protect against other neurodegenerative diseases, such as Huntington’s disease and Parkinson’s disease.
However, further human studies is needed to fully elucidate its effects on humans.
It may help you live longer.
Its ability to extend lifespan is probably one of the most exciting benefits of intermittent fasting.
Studies in rats showed that this eating pattern may help lengthen lifespan in a similar way as continuous calorie restriction. The effects were quite dramatic in some of these studies.
One of these studies showed that fasted rats lived 83% longer as compared with those that weren’t fasted.
Considering that intermittent fasting has known benefits for metabolism and all sorts of health markers, it makes sense that it can potentially help you live a healthier and longer life.
It simplifies your healthy lifestyle.
Eating healthy can be hard to maintain. It requires planning and cooking healthy meals every day.
If you do intermittent fasting, you need not plan, cook, and clean up after every meal as before. The fact that this eating pattern improves your health while simplifying your life at the same time makes it very popular among the life-hacking crowd.
Side effects
1. Hunger
Your body comes to expect food at certain times, especially when you’re used to eating over 4 meals a day. Your hunger typically peaks at breakfast, lunch, and dinner time. As you start doing intermittent fasting, you will absolutely feel hungry. But you’ll get used to it in the long run.
Whenever you feel a pang of hunger during your fasting period, you can combat that by drinking a lot of water to help satiate that habit of having to put something in your mouth and help you feel full and more alert.
One thing you’ll learn during your intermittent fasting is that sometimes what you thought was hunger was actually just thirst or boredom.
To help curb your hunger, you can drink black coffee and tea. In addition, try to keep yourself busy, get enough sleep, and refrain from doing strenuous workouts in the first few weeks to avoid feeling hungry. Another way to prevent hunger is to eat enough the day before and get your fills of healthy fats, protein, and carbs.
2. Cravings
Extended periods of not having to eat something can sometimes lead to cravings. There’s a tendency for you to just think about eating, and that’s when your cravings kick in. You might also find yourself more likely to crave refined carbohydrates or sweets since your body is looking for that glucose hit.
Keep yourself occupied so that you can’t find time to think about food. And during your eating window, be sure to indulge a little of your cravings so you can satisfy those cravings.
3. Headaches
As you transition to this new eating pattern, it’s not uncommon for you to experience dull headaches that come and go. Make sure to drink adequate amounts of water during your fasting and eating windows to avoid dehydration. Headaches can also result from decreased blood sugar levels and stress hormones so try to remain stress-free as much as possible during your intermittent fasting.
4. Low energy
Intermittent fasting makes you feel a little sluggish for the first couple of weeks as you can no longer get the constant source of fuel you used to have from your usual eating pattern. As much as possible, do not exert much energy and try to keep your day as relaxed as possible. Take a break from your intense workouts first and get extra sleep.
5. Irritability
Feeling hungry sucks. When your blood sugar levels drop or you’re experiencing other side effects of intermittent fasting like low energy or headache, you can expect to feel a little cranky. You can deal with this by staying away from things and people that can annoy you and focus on doing something that makes you happy instead.
6. Bloating, constipation, and heartburn
Acid produced by your stomach helps digest your food. So when you’re not eating anything, you are likely to experience heartburn, which can range from mild discomfort to full-on pain. To cure this, just keep drinking tons of water and avoid greasy, spicy food during your eating window. If symptoms persist, speak with your doctor right away.
If you’re not staying hydrated during intermittent fasting, you may also experience constipation, bloating, and discomfort.
Drinking adequate amounts of water is the best way to prevent this side effect. It also helps prevent headaches and makes you feel more energized.
7. Overeating
At the beginning of your intermittent fasting journey, you tend to overeat either because you are so excited about food or you heard calories don’t matter. To keep your portions under control, planning out your meals ahead of time is a good idea.
Feeling so famished from your fasting period may also cause you to overeat; you might end up eating way more than your normal portions.
8. Feeling cold
You may also experience cold fingers and toes when your blood sugar decreases. To combat this, you can simply take warm showers, avoid being outside in the cold for prolonged periods of time, sip hot tea, or wear extra layers.
These side effects of intermittent fasting may only be temporary. It takes some time for your body to adjust to the new eating pattern. If you have an existing medical condition, you should not start doing intermittent fasting unless you get a recommendation or approval from your doctor.
This is particularly important if you are underweight, suffering from diabetes, having problems with blood sugar regulation and low blood pressure, taking medications, or if you have a history of eating disorders. Pregnant and lactating women, as well as those with a history of amenorrhea, are also discouraged to do intermittent fasting without prior consultation with a doctor.
Basically, intermittent fasting is absolutely safe. Nothing is really dangerous about not eating for extended periods of time if you are well nourished overall.
Who Should Avoid or Be Careful with Intermittent Fasting?
Although intermittent fasting has potential health benefits, it is certainly not for everyone.
People with a history of eating disorders or those who are underweight should not fast without prior consultation with a health professional. Otherwise, it can be harmful for them.
Some evidence shows that this eating pattern may not be as good for women as it is for men. For example, a study found that intermittent fasting improved insulin sensitivity in men but worsened blood sugar control in women.
Some studies in rats showed that intermittent fasting can cause female rats to miss cycles and make them infertile, masculinized, and emaciated. However, further human studies are necessary.
Several anecdotal reports showed that the menstrual period in women stopped when they started doing intermittent fasting and went back to normal when they stopped IF and resumed their usual eating pattern.
Women, therefore, should be cautious with intermittent fasting. They need to follow separate guidelines like easing or stopping intermittent fasting immediately if they experience any problems like absence of menstruation.
Women who are trying to conceive or having issues with fertility should consider holding off on intermittent fasting.
Frequently Asked Questions
Below are answers to some of the frequently asked questions about intermittent fasting.
1. Am I allowed to drink liquids during the fast?
Yes. Non-caloric beverages like water, tea, and coffee are fine. You can put small amounts of milk or cream to your coffee, but don’t add sugar. Coffee can blunt hunger so it can be even more beneficial during a fast.
2. Is it okay to skip breakfast?
Skipping breakfast is okay as long as you eat healthy food for the rest of the day.
3. Can I take supplements while doing intermittent fasting?
Yes, you can. But keep in mind that there are some supplements that work better when taken with meals.
4. Can I work out while fasting?
Yes, working out during a fast is fine. You can take branched-chain amino acids (BCAAs) before a fasted workout. These products are available online.
5. Will fasting result in muscle loss?
All methods that lose weight can result in muscle loss. That is why it is highly important that you keep your protein intake high and consider lifting weights.
6. Can fasting lead to reduced metabolism?
No. Studies actually found that short-term fasts can improve metabolism. However, fasts that are longer than 3 days can suppress metabolism.
7. What should I eat when breaking the fast?
When you’re done with your short-term intermittent fasting and now ready to eat, try to stick to all the metabolic benefits you’ve gained from intermittent fasting. Stay away from sugar and junk food, and break your fast with cooked veggies, meat, and other low glycemic foods. If you’ve had a fast for a longer period, slowly consuming something that is easy to digest like a smoothie is a great idea.
8. Can my kids fast?
Allowing your kids to do intermittent fasting is probably not a good idea.
Should You Try Intermittent Fasting?
Although there’s nothing dangerous with not eating for extended periods of time, intermittent fasting is not something that everyone can do and should do.
There are a lot of lifestyle strategies to improve your health, like exercising, eating nutritious food, and having enough sleep. These strategies are still the most important factors that you should work on.
When it comes to nutrition, there is no such thing as a one-size-fits-all solution. The best diet plan for you is the one that suits your physical health and lifestyle, and the one you can sustain in the long run.
It is important to note that intermittent fasting can be great for some healthy and well-nourished individuals, and not for others. If you’re doing great with intermittent fasting, it can be a very powerful tool to achieve weight loss and improve your health.
If you’re planning to start with intermittent fasting, hope this article has given you all the information you need.
Getting Started
It’s not unlikely that you’ve done many intermittent fasts in your life. If you haven’t eaten your breakfast for the day, then you’ve probably already fasted for over 16 hours. Some people usually eat this way because they just don’t feel hungry in the morning.
For most people, the 16/8 method is the easiest and most sustainable way of intermittent fasting. You might consider trying this out first before going to a more advanced fast like the 5:2 diet or eat-stop-eat.
16:8 diet power foods
If you do the 16/8 method, try to stick to these 16:8 diet power foods:
- Whole grains, e.g., rice and oats
- Fruit, e.g., berries and oranges
- Protein, e.g., meat and poultry
- Vegetables, e.g., leafy greens and broccoli
- Healthy fats, e.g., avocados and coconut oil
You can also fast whenever you feel like doing it by just simply skipping meals from time to time when you don’t have time to prepare your meals or when you don’t feel hungry at all. You basically need not follow a structured intermittent fasting plan to reap some of its potential benefits.
You can try the different approaches and see for yourself which one works best for you.
Conclusion
There are various methods of intermittent fasting: the 16/8 method, the 5:2 diet, the eat stop eat, the alternate-day fasting, the warrior diet, and the spontaneous meal skipping.
If you’re doing intermittent fasting for the first time, you can start off with the easiest and most sustainable method—the 16/8 method. Once your body adjusts with the new eating pattern, you can slowly jump up to a more advanced one. The best way to identify which method is best for you is to try them.
Some people believe that this eating pattern may not be as beneficial for women as it is for men. Intermittent fasting can be a very powerful weight loss tool for some well-nourished individuals, but it certainly is not for everyone. People who are underweight, those who have underlying medical conditions, and lactating or pregnant women should not fast without consulting with a doctor first.
This eating pattern can have mild side effects that will last for the first couple of weeks. It’s important to be informed of its side effects so you know how to combat them when they occur.
Diet quality is very important in doing intermittent fasting. Make sure to refrain from overeating unhealthy foods during the eating periods. You can’t expect to lose weight and boost your health if you don’t stay away from unhealthy foods.
READY TO GIVE INTERMITTENT FASTING A TRY? WAIT!
You are not being told about many of the most important fasting breakthroughs being discovered by leading doctors and medical research centers.
There’s no big conspiracy.
It’s just that these breakthroughs usually don’t get much publicity.
That’s because they’re reported in medical journals intended for doctors such as The New England Journal of Medicine… The Journal of the American Medical Association… Lancet… The American Heart Journal… among many others.
Or, in some cases, these discoveries are made in prestigious health centers in other parts of the world, and receive little or no coverage in the US media.
In still other cases, highly respected medical doctors uncover these breakthroughs in clinical studies in their own private practices. They report their findings to professional medical societies, but these discoveries often escape the notice of the mass media.
All of this leaves gaping holes in the health information you should be getting. Yet these “under-reported” discoveries can be of tremendous importance to you and those you love.
That’s why we created My Health G.O.A.T. (Greatest Of All Time).Until My Health G.O.A.T. came along, if you wanted to try to keep on top of new intermittent fasting developments and scientific breakthroughs, you would have to subscribe to a shopping cart full of professional medical journals and newsletters.
And you’d have to spend a king’s ransom for the privilege!
You might also have to get a medical degree to understand many of the articles. But now that’s changed, thanks to My Health G.O.A.T.
Here are our top 11 articles you can read right now that will help give you a shortcut to success during your health and wellness journey as you learn more about intermittent fasting:
