Learn what intermittent fasting is, how it can benefit your health, and how you can get started as a beginner.
It’s official. Intermittent fasting has made its way into the mainstream conversation about health and wellness. It’s making headlines, it’s the subject of clinical studies, and it’s a popular biohack for many low-carb high-fat believers (myself included).
But, if you’re new to intermittent fasting, you might feel a bit overwhelmed as you think about embarking on your first fast—which is very understandable.
Modern Western diet culture has shunned fasting for a long, long time. We are so accustomed to pressing a button and having a sugary, processed, carb-rich Frankenfood snack whenever we want, that we cringe at the idea of not eating—even for a short period of time.
The truth is, intermittent fasting, when done right, has some profound health benefits. It’s been scientifically linked to weight loss, improved blood sugar control, healthy brain function, and cancer prevention, to name a few.
In this beginner’s guide, we’ll cover all the basics so you know what fasting is (and what it is not), how it can benefit your health, and how you can get started as an intermittent fasting beginner.
What is intermittent fasting?
Before we launch into the benefits of intermittent fasting, let’s determine exactly what intermittent fasting is and what it certainly is not.
Intermittent fasting is defined as a willing abstinence or reduction in food, beverage, or both for a defined period of time. In other words, intermittent fasting is an eating pattern where you cycle between periods of eating and periods of abstaining from food. The parameters are determined by you and your healthcare provider. You are in full control of when you fast, how you fast, and when you break your fast.
Contrary to popular belief, intermittent fasting is not the same as starvation. Starvation is food restriction not by choice for an undetermined period of time. It can have serious implications for both physical and psychological well being and is markedly different than the fasting process.
In terms of food intake, the body has two primary modes. You’re either in a “fed” state, meaning you are actively eating and digesting food, or you’re in a “fasting” state, meaning you are not presently eating or processing food.
Really, when you think about it, you already practice fasting to some degree. For example, if you eat a big dinner at 7:00 pm and conk out on the couch until 7:00 am the next morning, you’ve been fasting for about 12 hours.
It makes sense, then, that the words break and fast are squished together to form the compound word we know and love: breakfast. You break your fast every morning when you wake up and have your first meal.
So, when you incorporate intermittent fasting into your daily routine, you’re intentionally choosing when you’ll eat and when you won’t eat. Intermittent fasting is simply a more structured eating schedule that allows you to take breaks from digesting twenty-four-seven—a process that leaves your body run down and, quite frankly, makes it sick.
What are the benefits of intermittent fasting?
Today, we’ll cover three profound benefits of intermittent fasting, though it’s important to know that fasting has been linked to many other desirable and positive outcomes.
In addition to the benefits below, intermittent fasting has been shown to improve blood cholesterol profiles, reverse type 2 diabetes, aid in cancer prevention, and increase longevity.[1, 2, 3]
Let’s get down to the good stuff. Here are three benefits you can enjoy when you practice intermittent fasting.
Way back when, humans were hunters and gatherers. We got most of our food from foraging plants and hunting animals. Because the species was nomadic, humans were at the mercy of natural events like hurricanes, tornadoes, and droughts. When they couldn’t hunt or gather food, they went without it.
Fast forward to our post-modern industrial food landscape, and we’ve changed the way we do business. Since our hunter/gatherer days, we’ve used our big brains to mass-produce food. We put chemicals on our food so it grows fast, preserve it so it doesn’t go bad, and alter it so it tastes different. We’ve even engineered the molecular components of our food with things like artificial trans fats and artificial sweeteners.
Because we’re inundated with food all the time, we’ve grown a bit spoiled. Our bodies have become conditioned to expect foodfrequently, and they get a little demanding when they want more. Have you ever been crippled with hunger by noon because the last thing you ate was a bowl of corn flakes at 9 am? Or maybe you’ve felt cranky and thought to yourself, “Oh, I haven’t eaten dinner yet.” That’s simply your body demanding to be fed. It’s hangry. It doesn’t need food, but it sure does want it.
Our ancestors likely didn’t have these reactions. They weren’t so picky about their eating habits because they were metabolically flexible. In other words, their bodies were well-versed in burning stored fat when food wasn’t available. In modern America, we’ve become disconnected from the natural biological process of burning body fat as fuel.
When you practice intermittent fasting, you hit the pause button. You stop the onslaught of food and let your body use some of its stored fat for energy instead. This, of course, is perfectly natural, since our bodies are still wired the same as our hunter/gatherer ancestors; they’re designed to burn stored fat for fuel when they must.
It’s no surprise, then, that intermittent fasting leads to weight loss. It allows the body to dip into its fuel reserves and burn fat. This results in a leaner, more efficient, and healthier body composition.
Immune system reboot
Another benefit of intermittent fasting is its ability to recoup the immune system. Six years ago, a study showed that a simple three-day fast can all but reset the immune system entirely. This, of course, can lead to other benefits like decreased inflammation, lower blood pressure, and better cardiovascular health.
Fasting allows your body to begin a process called autophagy. This is essentially your body’s “self-cleaning” process. Autophagy rids the body of weak or damaged cells to make way for new ones. You can think of autophagy as your body taking out the trash. If it doesn’t take the trash out, it’ll pile up and you’ll be inundated with damaged cells. Damaged cells often lead to disease, disorder, and discomfort.
A recent study by Valter Longo proved that fasting lowers the white blood cell count, thereby signaling the immune system to produce more. With more white blood cells being produced, the immune system is replenished with new, strong fighters to keep you healthy.
Fasting also lets your body rest so it can focus on important maintenance processes. In a world where we are constantly on the go, some profound rest can go a long way.
Mental sharpness and increased concentration
Most people worry that going hungry will dull their thinking abilities or make them lethargic. But, contrary to popular belief, fasting has incredible benefits to brain function.
When we think, again, about our hunter/gatherer ancestors, this makes good sense. It was important for them to have sharp senses and mental clarity during times of fasting. Otherwise, they wouldn’t be able to secure their next meal.
If fasting promotes keen sense, mental sharpness, and increased concentration, then the opposite is also true. When you are full or satiated, you feel lazy and sleepy. Think about it. How did you feel the last time you ate four slices of pizza? Or 3 donuts? Or a burrito the size of a small shoebox? You probably felt like you were in a food coma.
Clear thinking and increased concentration have been known benefits of intermittent fasting throughout history. Ancient Greek philosophers would fast for days on end, not because they felt obligated to, but because they thought it would sharpen their thinking abilities. It’s taken modern science a long time to prove what they knew intuitively so long ago.
How to practice intermittent fasting
If you’re excited to get started, it’s important to know that there really is no one right way to practice intermittent fasting. Most beginners start by fasting for a few hours and work their way up from there.
Here are a few popular fasting strategies to work intermittent fasting into your routine. But always remember that you are in total control of your fasting journey, so you can follow the regimes below or modify them to fit your preference.
Fasting for less than one day
Fast for 16 hours: To fast for sixteen hours, you’ll eat all your meals within an eight-hour time period and fast for the remaining sixteen hours of the day. For example, you might eat all your meals between 11 am and 7 pm.
Fast for 20 hours: This fast involves a four-hour eating window and a twenty-hour fast. For example, you might eat between 2 pm and 6 pm and fast for the other twenty hours. This usually involves eating one larger meal or two small meals per day.
Fasting for more than one day
Fast for 24 hours: You may choose to fast for twenty-four hours at a time. Some people popularly call this fast the “one meal per day” fasting regime. For example, you might choose to eat dinner and then not eat again until dinner the following day.
Fast for 48 hours: Some people like to incorporate a forty-eight-hour fast into their weekly schedule. This fast involves eating regularly for five days and fasting for two days. During fasting days, calories should be restricted to 500 calories per day, though you can choose to spread them out however you’d like.
Extended fasting: If you plan to fast for more than two days, you should consult a healthcare provider. While people have surely fasted for extended periods of time, extended fasts introduce some additional difficulties, so checking in with your healthcare provider is essential. They may recommend a multivitamin or other supplement to avoid micronutrient deficiency during your extended fast.
How to set yourself up for fasting success
It’s okay if you’re not a fasting pro on your first go. Like anything else, fasting takes practice and patience. You’ll up your chances of success and achieve metabolic flexibility sooner if you eat a low-carb, high-fat diet in between fasts.
I’m a big proponent of this simple method: test, assess, and address. Make your body a living laboratory. Test a method, assess how you feel, and make changes accordingly. In time, you’ll find the perfect rhythm and go from intermittent fasting beginner to metabolically flexible fasting pro.
If you are taking daily medications, especially for diabetes, have had trouble with eating disorders like anorexia or cachexia in the past, are pregnant or breastfeed, or if you are under 18 years old, you should talk to a health care professional to determine if intermittent fasting is right for you.
To talk with a metabolically trained professional, click here. These physicians are experts in metabolic approaches to wellness and would be delighted to speak with you and help you achieve metabolic flexibility.
For more information on fasting, check out our article “Intermittent Fasting FAQs: Your Most Common Questions Answered” or drop your questions and fasting experiences in the comments section below!