Intermittent fasting is a way of eating that involves abstaining from food for a certain time period, followed by eating whatever you want. This diet has been gaining popularity in recent years because it can help with weight loss and offer other health benefits.
In this complete guide to intermittent fasting, we will talk about what intermittent fasting is, how to do it, the pros and cons of intermittent fasting, plus cover common questions and concerns that you might have surrounding this way of eating.
The idea behind intermittent fasting is simple: eat all your calories during a certain window each day, then fast for the remaining time (including sleep) every night. Sounds pretty simple, right? Well, it can be, but there's a bit of information to know before you get started.
Ready to get started? Let's dive right in!
Complete Guide To Intermittent Fasting
What is intermittent fasting?
Intermittent fasting is a dietary pattern that restricts the time window in which you can consume food. There are many intermittent fasting forms, one of the most popular forms is 16:8; for 16 hours, you fast and only eat during an 8-hour window.
This can work with any time frame, but the minimum recommended time to spend fasting every day is 14 hours. You can do intermittent fasting on any schedule, but most people fast from dinner (or supper, as I call it, until lunch the next day. This way, a giant chunk of your fasting time is being done while you're sleeping!
Examples of Fasting/Eating windows:
- 23:1 - OMAD (one meal a day)
- 5:2 - 5 days normal eating, 2 days at restricted calories (500)
- Alternate day fasting - eating one day, fasting the next, and so on
- Extended fasts - 24 hours or longer
However you want to start with intermittent fasting, it's important to implement a schedule that will work with your lifestyle, job, kids, etc. It can be a little difficult to adjust initially, but the majority of people who stick with it for a bit say it gets much easier the longer you do it for.
How does intermittent fasting work for weight loss?
Intermittent fasting is a tool for weight loss. It's not the only way to lose weight or start eating healthier, but it can be an effective method when used correctly.
Intermittent fasting uses time-restricted feeding cycles that allow you to eat all of your food in a shorter time window and then fast for the rest of the day or night.
The general idea behind intermittent fasting is that there are fewer hours in which to consume calories, limiting how much one can eat during any given period, leading them to eat less overall and facilitate weight loss.
It’s not about skipping meals or starving yourself, but rather limiting your eating window to consume the necessary calories your body needs in a set amount of time and not consuming anything outside of that window.
How do I start intermittent fasting?
The first thing you need to decide when you start intermittent fasting is your eating window. It can be any time of day you like, but many fasters like to stop eating around suppertime and start eating again around lunchtime the next day.
If you're a person who likes to hit the hay early, this will be a great schedule for you; you won't be up late with a grumbling belly.
Whatever schedule you decide on, it's important to remember that the real benefits of intermittent fasting start at about 14 hours of fasting (more on that in a bit!).
Next, you need to determine your TDEE (Total Daily Energy Expenditure). This is an estimate of how many calories your body is burning per day to exist. There are handy TDEE calculators available online which simplify this process.
Some people are under the notion that you can eat whatever you want when you are intermittent fasting, and this is true - up to a point. The basics of weight loss still apply. If you are eating more calories than your body is burning off, you will not lose weight. CICO (calories in calories out) - your intake has to be smaller than your output.
After you have this information, it's time to set some goals. For this complete guide to intermittent fasting, we're sticking to weight loss; it's the number one reason people start on this way of eating, though there are other benefits!
Here's some ideas of the goals you might want to write down:
- How much weight do I want to lose?
- How much weight am I looking to lose per week?
- I want to fit into (insert jean size here)
- I want to be able to run xxx amount, etc.
Your goals are going to be personal, and writing them down so you can go back to them is something that can keep you motivated in the long run.
Note - It's recommended to shoot for a goal of no more than 2 pounds of weight loss a week. Slow and steady wins the race here. Crash dieting may get the pounds off fast, but it is much more likely to all come creeping back if you try to lose in an unsustainable way.
Next step - Take pictures!!!! Trust me; you're going to want them to compare your before and after. When trying to lose weight, we get stuck on the scale number and don't notice the real changes that are happening with our bodies. Taking pictures periodically helps you to look back and see how far you've come and can be an incredible motivator if you're losing steam.
Now that you've got all that down, there's nothing left to do but start! When it is time for your eating window to begin, start eating. When it is time for your fasting window to begin, stop eating and don't eat anything until your eating window opens back up.
Yes, it really is that simple.
Can I eat anything I want when intermittent fasting?
There are many benefits to intermittent fasting. It can help you lose weight, improve your gut health, and reduce the risk of chronic diseases like diabetes.
However, one concern that people have is whether they can eat whatever they want when intermittent fasting. The answer is yes!
Intermittent fasting typically involves periods of eating less food followed by a period where normal caloric intake resumes. This means that there are no restrictions on what you can eat during these times as long as it fits within your calorie limits for the day and your goals for weight loss.
Intermittent fasting focuses on when you eat rather than what you eat. You don't need to go on any crazy diets, nor do you need to go Keto for intermittent fasting to work for you (though this can have benefits).
The beauty of intermittent fasting is that it will work for you without changing your food habits that much; that being said, 1000 calories of ice cream isn't the same as 1000 calories of vegetables. Though you can technically still lose weight this way, you're wreaking havoc on your body by doing so.
To simplify things, especially for people who are new to intermittent fasting, don't change a thing at first. Get used to the fasting/eating window, and then you can start making adjustments from there.
Is there a right way or wrong way to do intermittent fasting?
There is no "right or wrong" way to intermittent fasting.
People can do intermittent fasting in many ways; some choose to do it by skipping breakfast, while others choose only to drink water or black coffee (or nothing at all), and still, others choose to eat one meal per day.
The only way you will be successful and stay consistent with intermittent fasting is by figuring out what works for you personally.
There are some common mistakes that people make, however; keep these in mind:
Going way overboard at first
We get it. This is exciting! But starting on the wrong foot with intermittent fasting can set you up for disaster. If going from eating 3 normal-sized meals or 6 small meals per day to only a four-hour window, you might crash and burn.
Instead of jumping into 16:8 without easing yourself into it first, gradually extend the times and start by trying 12-hour fasts, then 14-hour ones; once you're comfortable, you can extend this.
You're eating too much outside of your fasting window
One of its benefits of intermittent fasting compared to other diets, like restricting food groups, is flexibility. You choose when and what to eat, and the only rule is you stick to your eating window.
But with this flexibility comes responsibility: if your daily caloric intake stays consistent regardless of whether you are following IF or not, you won't lose weight.
Make sure those calories add up so they're less than what goes out each day!
You're consuming calories in your fasting window
Even something as simple as the taste of sweetness can cause your brain to release insulin, which will break a fast (looking at you, diet soda...). Many things have added sugar or sweeteners, including medications, pain relievers (sugar coating), and even toothpaste and mouthwashes!
True intermittent fasting means you ingest nothing aside from water. This can be stretched and is by many, to include black coffee and some teas.
We'll have more in-depth guides into all of the specifics in the future, but these are the main ones to watch out for.
Why you should fast for at least 14 hours
Studies have shown that 12-hour fasts are not long enough to reap many of the benefits of intermittent fasting. To get the most out of intermittent fasting, it is best to fast between 14 and 18 hours per day.
This can lead to significant weight loss benefits as well as ketosis, shifting your body into fat-burning mode. This, of course, can be impacted by a few factors, like what you ate last. 16-hour fasting windows are great daily routines that give you ample time to eat (8 hours).
For those looking to benefit from autophagy, this doesn't generally kick in until around 24 hours of fasting time.
Do I have to do Keto when intermittent fasting?
To lose weight with intermittent fasting, you don't need to eat keto or be in ketosis. The benefits of following intermittent fasting will be realized whether you go with keto or not.
The Keto Diet is a low-carb, high-fat diet. The goal of this type of diet is to put your body into a state known as ketosis. Ketosis occurs when you don't have enough carbs for your cells to use as energy and instead burn fat stores for fuel.
This leads to weight loss because the body becomes more efficient at breaking down stored fats than carbohydrates. Many benefits come with being in ketosis, such as increased mental clarity, better moods, and improved physical endurance.
Boosting your keto diet with intermittent fasting can help make the process faster and lead to even more weight loss. However, it may not work for everyone; possible side effects from combining the two include overeating on non-fast days or feeling moody and fatigued because of a lack of consistent energy intake.
After you've gotten comfortable with intermittent fasting, you might want to explore some ways to get better results. Keto may be an option, but it is absolutely not necessary for intermittent fasting.
The benefits of intermittent fasting
Intermittent fasting isn't just for weight loss. Many benefits come with it, including increased focus and clarity, higher energy levels, and the ability to handle dangerous eating habits that can have lifelong effects.
Intermittent fasting can reduce insulin resistance and lower your chances of Type 2 Diabetes
Studies have shown that intermittent fasting can decrease insulin resistance and improve the body’s response to sugar in people who are overweight or obese with prediabetes or type 2 diabetes.
Intermittent fasting has also been found to positively affect insulin sensitivity, glucose regulation, and type 2 diabetes in animal models.
Intermittent changes your hormones, function of cells, and your genes
There are beneficial changes in several genes and molecules related to longevity protection against disease with intermittent fasting.
Fasting has been shown to reduce your blood sugar and insulin level while simultaneously increasing human growth hormone levels (HGH). Higher levels of HGH can lead to more fat loss and greater muscle gains.
Intermittent fasting reduces inflammation and oxidative stress
It has been shown to reduce inflammation and oxidative stress, which can help prevent disease. Intermittents fasting helps the immune system by reducing inflammation and reactive oxygen species (ROS).
Inflammation occurs due to an irritant or infection from the body's response. ROS is caused by excessive production in cells that may lead to cell damage depending on how they react with other molecules around them.
When someone undergoes intermittent fasts, it reduces both problems for their health: lessening inflammatory responses; decreasing ROS levels, which leads to cellular damage- all without having any negative effects!
Intermittent fasting may be beneficial for heart health
Intermittent fasting can also help improve blood pressure and resting heart rates, making it a healthier choice for those who are looking to get into shape while improving their heart health at the same time.
Intermittent fasting can induce autophagy
One of the lesser-known benefits of intermittent fasting is autophagy. Autophagy is the process by which cells break down their own components for recycling to sustain life under starvation conditions or during other stressful environmental changes such as infection or injury.
This breakdown and turnover of cells mean that damaged cell parts can be replaced with new ones when made available from sources like amino acids from our muscles (a process called proteolysis). It may also help reduce the risk of certain cancers through this method.
Intermittent fasting may help reduce the risk of cancer, and possibly prevent it
Intermittent fasting could decrease the risk of cancer and side effects caused by chemotherapy. This is because it can lower insulin levels, which reduces inflammation that may lead to tumour growth. Animal studies also suggest intermittent fasting might delay tumours from developing.
Intermittent fasting is great for your brain health
Intermittent fasting has various metabolic features that can be important for your brain health. This includes a reduction in oxidative stress, inflammation and blood sugar levels, and insulin resistance.
In addition to this, intermittent fasting may increase new nerve cells' growth, which is beneficial to brain function when damage occurs due to stroke.
Intermittent fasting could extend your lifespan
That's right, intermittent fasting could help you live a longer and healthier life!
Studies show that it may extend lifespan in the same way as continuous calorie restriction. And regular fasting is associated with lower heart failure rates, meaning your chest will be happy (and so will everyone else).
And last, but certainly not least:
Intermittent fasting can help you to lose weight and keep it off
The body breaks down carbohydrates into glucose, which cells use for energy or convert into fat and store later. Insulin is a hormone that allows cells to take in glucose. Having low levels of insulin in the body causes this process to be reversed. In this state, the cells are more readily able to release glucose and fuel your body.
By repeating this process, you can definitely lose weight. Intermittent fasting can also help you reduce your BMI by restricting the number of calories you're able to take in during your eating window.
When you fast for a day or two at a time on an intermittent basis, your body will gradually adapt and become accustomed to lower calorie intake levels. It seeks out alternative sources of energy to maintain basic functions like heart rate regulation.
This is called metabolic adaptation, where our metabolism changes; we consume less food over long periods and primarily use stored fat instead of sugars from carbohydrates produced by digesting more processed foods.
The drawbacks and risks of intermittent fasting
Intermittent fasting is all the rage right now. But before you jump on board, it's important to know that there are some risks and drawbacks associated with it.
Intermittent fasting can make it harder to get over a craving. It's been shown that people who fast are more likely to binge eat, and overeating is unhealthy in general because of the increased risk for obesity and other problems related to weight gain like diabetes.
Fasting also leads some people to experience an increase in cortisol, a stress hormone linked with food cravings; this may lead them back into eating mode again quickly after breaking their fast on days where hunger strikes hardest.
Another thing you might notice during intermittent fasting periods: your stomach growling! This happens when our shift your eating window to a restricted time; when you'd normally stuff a snack in, now you won't be able to.
Intermittent fasting can make you feel tired because your body is running on less energy than usual. Since intermittent fasting may also boost stress levels, it could disrupt sleep patterns.
Intermittent fasts are sometimes associated with dehydration if people forget to drink when they're not eating; this might happen more often than we realize. Water is beneficial for you in so many ways - make sure you're getting enough of it!
People who do an intermittently fasted diet will likely have periods of feeling irritable due to being hungry or having trouble sleeping at night after a prolonged period without food.
Women, in particular, have one drawback that men don't. It is possible that when intermittent fasting, women may experience irregular menstrual cycles. If you are trying to conceive, this can be very detrimental.
Despite the drawbacks, there are a ton of benefits that may outweigh them. Keep an eye on how you're feeling and if you need to adjust something, change your eating window, or take a break - DO IT! This isn't supposed to feel like punishment.
How do I manage hunger while intermittent fasting?
When you are intermittent fasting, there will be long periods of time when you go without eating during your fasting window. This can lead to some serious hunger pains that can be hard to manage.
Keep in mind that being hungry won't kill you. We as a society are so used to immediate gratification that many of us don't even know how to recognize true hunger anymore.
One of the most important things to remember while fasting is that your feelings of hunger will pass like a wave. Many people worry about feeling hungry during intermittent fasting, but this won't happen as long as you ignore it and drink something hot or cold--coffee, tea, water. It'll often just go away!
Can I exercise while intermittent fasting?
Yes, you can exercise while intermittent fasting. Your body has plenty of stored energy that can be used for fuel during a workout. In some cases, though, eating before exercise may increase performance - like during long-duration aerobic exercises. Fluid intake and replenishing sodium are also important when fasting around those times.
Is there anyone who shouldn't intermittent fast?
Intermittent fasting is not for everyone. Here is a breakdown of who should NOT be intermittent fasting:
- Anyone at risk of an eating disorder
- Pregnant or nursing women
- Underweight individuals
- Individuals under the age of 18
The following individuals should always consult with a doctor before starting intermittent fasting:
- Have diabetes or blood sugar regulation issues
- Are on any medications
- Have low blood pressure
- Are trying to conceive
- Are a woman with a history of amenorrhea
How to get the most out of intermittent fasting
Hopefully, this complete guide to intermittent fasting answered the majority of questions you had about this way of eating.
Here's a few final tips to help you get the most out of intermittent fasting:
- Stick to your eating window
- Extend the length of your eating window
- When you've adjusted, get your diet in check and add in healthier foods
- Hit the gym - more specifically, the weights.
- Avoid foods that spike your insulin - sugar, white bread and pasta, pop, etc.
- Drink a lot of water - like, a LOT of water
- Keep yourself busy. When hunger strikes, ride it out by drinking lots of liquids or having a cup of hot tea
- Avoid binge eating by making sure you are consuming enough calories during your eating window
- Stop if you're having serious problems adjusting and it is affecting your mood, sleep cycles, or you have other health concerns that pop up
Still have questions? Let me know in the comments below!