Generally speaking, the topic of fasting has been in the limelight for a number of reasons. One of those is that people believe it is healthy and can help promote weight loss. Others argue that this practice is not necessary and could potentially result in more harm than good. But, if you weed through all these debates, you will still notice that quite a number of people still embrace the technique.
The question then shifts from, is it necessary to how long can one participate in this approach and still be considered safe. There is a notion that extending one’s fasting window will quicken how fast one sees their results. It is especially thought to be the case if you are implementing this practice for weight loss.
Like exercise, you may be tempted to overdo this practice and in the end, it will do more harm than good. You are certainly advised to abide by the stated or recommended fasting window to make sure you gain the most without further jeopardizing your health. In this piece, we are going to analyze and answer the question of how long is it safe to fast.
Fasting – What Is It?
Fasting refers to when you willingly refrain from food consumption for a specific duration of time. This could be from some hours to a day or more. The length of time primarily depends on your intentions of undertaking this practice.
Some people embrace this practice as it is ingrained into their view on life. So, fasting for them is a way of declaring their faith to their spiritual being. Outside of this, one may embrace this practice merely for its benefits.
Experts acknowledge that fasting might have some health benefits (3). They include:
Promoting Weight Loss
When you refrain from eating, your body is unable to acquire energy from food. As a result, it starts to break down glucose in the muscles and liver, eight hours after your last meal. When the glucose is all used up, the body now starts breaking down your body fat. This is a normal process that happens every night while you are sleeping between your evening meal and your first meal of the next day.
If fasting results in you eating less food overall than you did without fasting, this can result in weight loss. If you still consume the same number of calories but just pack them in to fewer hours of the day, you will probably not lose any weight.
Improving Your Emotional Well-Being
When the body starts breaking down your stored fat, it provides an opportunity to remove toxins that may be stored in that fat tissue.. Fasting, like exercise, can also promote the release of hormones responsible for making you feel good. Such sensations could positively impact your emotional well-being.
Helping With Autophagy
Autophagy is the process whereby the body gets rid of various body cells and organelles that are no longer functioning. The process gives the body enough time to regenerate new and better functioning cells.
Intermittent fasting is believed to promote autophagy as certain fasting techniques may activate the start of this process (11). You must consult with your doctor to determine the best intermittent fasting method to choose if your goal is autophagy activation. Otherwise, never pick a technique merely because it is said to work or has worked for someone else.
Fasting is also believed to positively impact the digestive system because you are giving the gastrointestinal tract a break from digesting food.. On the other hand, going too long without any food to digest can lead to dangerous consequences for the digestive system so be sure to discuss any fasting plans with your physician first.
Types Of Fasting
There are various types of fasting. Perhaps the most popular one is intermittent fasting. It occurs when you reduce your food intake or abstain from eating and drinking for a certain duration. You may or may not focus on reducing your caloric intake, depending on your goals.
You will find that many intermittent fasting diets pay close attention to the calories you are consuming. The 5:2 Fast Diet is one of the popular types of intermittent meal plans (3). It entails consuming your usual necessary calories for five days of the week and reducing the intake to 25% for the other two days, which should not be consecutive.
It might seem like a nice idea to try this technique, especially if you are contemplating on losing weight. However, never take it on before getting advice from a registered dietitian or doctor. The other type is the time-restriction approach. This involves abstaining from food consumption for a predetermined number of hours each day. You may know it as circadian rhythm eating.
Which Is More Efficient?
All these fasting methods have their pros and cons. So, it is tricky to acknowledge which is more efficient. The best way of recognizing what type to try is to consult a physician. Let them know your goals of trying this practice.
If they agree the technique can meet your needs, then they will advise on the best one. However, if they think this technique can do more harm, then they will recommend other actions.
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How Long Is It Safe To Intermittent Fast?
Since more people are into intermittent fasting, the question of how long you should try this technique is quite common. Luckily, there are various ways that offer options on different timelines to explain how long you should try it. They include:
Fasting For 12 Hours In A Day
This intermittent fasting method is quite straightforward. You are required to refrain from eating for twelve hours. The positive thing about this technique is that it can help in weight loss.
This is because fasting for a timeline ranging from ten to sixteen hours allows the body to start burning fat (6). The small fasting window makes this intermittent fasting method appropriate for beginners.
Fasting For 16 Hours
The technique gives you eight hours of eating. As a result, it has been dubbed the 16:8 method. In this method, men are usually suggested to adhere to this fasting window. However, women are only recommended to fast for only fourteen hours.
You should never jump into this method, and especially if you have never tried fasting. What is more appropriate is if you are looking to advance past the 12-hour intermittent fasting window.
Fasting For Two Days In A Week
The other way you can try intermittent fasting is by fasting for two days a week. The diet plan recommended in this method is the 5:2 diet. For 5 days of the week, you eat normally. For the other two days, you must refrain from eating anything above 500 calories for women and 600 calories for the guys.
Again, you should not fast continuously for two days. You need to take breaks in between the week. For example, you can fast on Tuesday and then try it again on Friday. You have to give yourself at least a one day break before continuing with your fast.
Alternate Day Fasting
There are several definitions of alternate fasting. For some, it entails abstaining from food consumption every other day. Alternatively, others define it as entirely refraining from solid meals whenever you are fasting.
In some cases, some people may allow for food consumption during these fasting days. However, the food or beverages consumed on fasting days should provide at least 500 calories ((6). Due to its extreme nature, this method is not effective for beginners. It is also not suitable for you if you have a severe medical condition. If attempted, it should be done under medical supervision, so talk to your doctor first.
Fasting For 24 Hours In A Week
This fasting technique involves a total refrain from food for 24 hours. It is also known as the Eat-Stop-Eat diet. Unlike the other intermittent fasting ways, this approach accommodates beverages. So, you can have tea and other calorie-free drinks besides water.
The 24 hours of fasting is no joke. This will take a toll on your physical and mental health. You most likely will feel dizzy, irritable and fatigued. It is better off to try this fasting method when you have medical supervision. Even so, experts recommend the 12 or 16 hours fasting methods over this.
The other technique of intermittent fasting is skipping your meals. This is widely practised by fasting beginners. The key to this approach is not continuously skipping meals but instead doing so occasionally.
You have the freedom to choose whatever meal you want to skip. It could be breakfast, lunch or dinner. You are expected to eat whenever you feel hungry or when you beat your set timeline.
Always pick a method you can stick to for one month (5). So, if this method is better suited to last you through the month, then prioritize it over the others. Again, always begin the technique only after attaining your physician’s go-ahead.
The Warrior Diet
You may guess from the name that this method is no joke and requires only warriors. It is the case. It is quite extreme and not suitable if you just gave fasting a chance. The method requires you to fast for twenty hours and eat in the 4-hour window.
As such, you are advised to eat a very huge meal at dinner. Before you take on this extreme technique, let your doctor know. They might advise against it due to your health history or if it cannot meet your goals.
The One-Meal-A-Day Diet
The other type of intermittent fasting entails eating only one meal in a day. You are supposed to fast for 23 hours and spend the remaining hour filling up your calories. So, if you have your meal at dinner time today, you would be expected to eat your next meal tomorrow only at dinner.
You should never exceed these 23 fasting hours as it could increase your risk to several conditions. You might end up with increased fatigue, low blood sugar and extreme hunger (7).
Therefore, even if this technique is bringing you some weight loss results, moderate on how often you practice it, and always discuss with your physician first. The goal is to ensure you lose weight safely and not use methods that further put you at risk.
How Long Is It Safe To Water Fast?
Water fasting entails a practice where you eat nothing and drink no beverage other than water. It was quite common in spiritual practices, but over time, it has been embraced in health and fitness.
The technique may help in weight loss, which explains why it is popular in the health and fitness industry. However, you should not try this approach without checking in with your doctor. You need their go-ahead to ensure your body is ready for such a transition.
There is no set time on how long you should water fast. This does not mean that you can try the practice for any amount of time. The recommended timeline for water fasting is from one to three days before eating (1).
You should not engage in water fasting any longer than this, and not at all without medical supervision.
Benefits Of Water Fasting In The Recommended Duration
If you try this technique and do it for the recommended timeline, then you may benefit from:
- Increased weight loss. Lack of access to carbohydrates will make your body break down stored fat for energy supply. The intended effect of this technique is weight loss due to continuous burning of stored fat. However any initial weight loss is likely water weight, because your body will first break down stored carbohydrates, which have water associated with them.
- May help people with various conditions. Some people believe that short-term water fasting might benefit people with conditions such as high cholesterol levels. Always first discuss with your doctor as many other common conditions can make it dangerous to fast.
Risks Of Water Fasting Beyond The Recommended Timeline
Even if you feel like your body can manage to go extra days, do not try it especially without any medical supervision. It can result in the following:
- Increased health complications, especially if you are underweight and/or older in age. It can also result in worsened health if you have a preexisting health condition.
- Excessive loss of weight. If you exceed this behavior, you might end up losing more weight than you intended.
How Long Is It Safe To Fast Your First Time?
If it is your first time fasting, then it is safer if you start with a time-restricted fasting method (10). There are numerous types of time-restricted methods. They include methods with a fasting window of 12 hours, 16 hours, 23 hours, and so forth.
It is quite unrealistic for a beginner to start with a fasting window that has so many hours. The key is always to start small and take baby steps to these huge fasting window periods. As a beginner, you can start with a 12-hour fasting period.
In this case, you will only be required to fast for twelve hours. To apply this method, you can wait until 8 a.m. to have breakfast, have your lunch whenever you like and finish eating dinner by 8 p.m. With time, you can sit down with your doctor and ask for approval to advance to another time-restricted fasting method.
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How Long Is It Safe To Dry Fast?
Dry fasting is another type of extreme fasting method. This means a complete refrain of solid food and water during the period you are fasting. It can be quite dangerous as it potentially causes dehydration and other severe health conditions.
Healthy people may be able to fast with water for some days without getting any complications (2). However, dry fasting for even a short time is dangerous, this is especially due to dehydration.
Fasting and especially dry fasting can be life-threatening if you prolong it. It is even more severe for diabetic people. Therefore, if you have diabetes, do not try any fasting method. Similarly, ensure you consult on the best dry fasting window with your physician to avoid health complications.
How Long Is It Safe To Fast For Weight Loss?
Studies have acknowledged that fasting can aid weight loss if it results in reduced calorie consumption. However, the results may differ. You may end up losing more or less weight than expected depending on how often and how long you fast.
Using fasting as a weight-loss method is no better than reducing your calorie intake to promote weight loss. Both methods have their pros and cons. If you want to lose weight safely, the goal is to first identify the best fasting method.
This will dictate how long you should fast to get your weight loss results. The best fasting techniques for weight loss usually recommend fasting for either 12 or 16 hours (9). These two fasting windows are quite manageable.
However, you can also use the 24-hour fasting method to promote weight loss. Before doing so, evaluate if this method is safe for you.
Other Tips On Safe Fasting
Besides being cautious of your fasting window, make sure you also take note of the following:
Dedication is vital, especially if your main focus of adopting this technique is losing weight. You will not lose weight by fasting once and less than the stated safe window. This has to be a continuous process.
What makes it tricky is because you must take care to pick a fasting method you can sustain without risk to your health. If you plan on fasting for three months for weight loss, pick a technique you will see through these months.
It is always advisable to start with a simple technique that is neither too demanding nor complicated. For example, you could start with meal skipping before extending to a fasting period of 12 or 16 hours. Remember that slow and steady wins the race, so, take it slow.
A healthy man weighing about 154 pounds has calories stocked to last him between one and three months (4). Ensure you learn your body type and other demographics like age, sex and weight before choosing a fasting technique.
You might end up choosing a method suitable for someone with different demographics. So, despite being obedient to the fasting window, you might end up suffering from other health complications.
The Bottom Line
Fasting is not a version of starvation. It is a willing process where you decide to keep away from food for a certain timeline and for various reasons. Despite what your goal is, ensure you never extend the fasting period without any medical supervision. It is dangerous and increases your risk to various health threats.
All these views and recommendations do not represent the advice of a physician on fasting. So, before you fast for the timeline we state, consult with your doctor.
- All you need to know about water fasting (2018, medicalnewstoday.com)
- Do Fasting Diets Work? (2020, webmd.com)
- Fasting: Health benefits and risks (2015, medicalnewstoday.com)
- How long can you survive without food? (2020, medicalnewstoday.com)
- How to begin intermittent fasting (2019, medicalnewstoday.com)
- Seven Ways to do Intermittent Fasting (2020, medicalnewstoday.com)
- Should I eat just one meal a day? (2020, medicalnewstoday.com)
- The 3 Day Diet (2019, webmd.com)
- What happens if you fast for a day? (2020, medicalnewstoday.com)
- What is intermittent fasting? Does it have health benefits? (2020, mayoclinic.org)
- What to know about 48-hour fasting (2020, medicalnewstoday.com)