How Does Intermittent Fasting Work? (+6 Intermittent Fasting Benefits)

Did you know back in the primal days of hunter-gatherer, there was no such thing as eating several small meals a day? The ancestral routine was to hunt food all day and eat just one meal every night. In fact, some days there may have been no food at all while other days may have been filled with bountiful harvests. This primal eating pattern is traditionally known as “feast or famine,” but we utilize a form of it today known as intermittent fasting.

Now, did you also know that the human body is naturally programmed this way—and that something amazing happens inside this way of eating? When you start intermittent fasting, it allows your body to go back to its primal programming and begin to use fat stores for energy! Plus it allows your body to rest and repair. 

Want to know more about intermittent fasting, including how it works and if it's right for you? Keep reading to learn more about the eating pattern so many have found success with!

What Is Intermittent Fasting? 

We’ve often been told that breakfast is the most important meal of the day. But what if I told you this is the furthest things from the truth—and that the many ways that intermittent fasting benefits your body is proof of this?

So, what is intermittent fasting? As noted above, intermittent fasting is an eating pattern based on primal practices when food wasn’t always readily available. It’s the practical approach of shifting between periods of unrestricted eating and restricted eating—meaning that you go short intervals of time without eating food. 

Now, people often wonder how to intermittent fast and, more specifically, how long they should do intermittent fasting. Research suggests that 16 hours is the optimal amount of time for creating the caloric restriction that happens during fasting and to also activate autophagy, which gives your cells a chance to perform a self-cleaning process. This is known as the popular intermittent fasting 16/8 approach, which allows for 16 hours of fasting and eight hours of eating. I personally practice this strategy and highlight its merits in my bestselling book, Glow15.

One of the easiest ways to follow the major rule of intermittent fasting—which is to go a significant amount of time without eating, such as 16 hours—is to simply skip breakfast and wait until mid-day to eat. You then eat from mid-day until dinnertime and then fast until the next day around noon.

How Does Intermittent Fasting Work?

Now that you know what intermittent fasting is and how to do it, let’s review how it works.

First, you should know that glucagon is a hormone released by the pancreas in response to low blood glucose, whereas insulin works in opposition to reduce blood glucose levels. When you fast intermittently, insulin levels decrease and glucagon increases, which has been shown to benefit metabolism, energy, mood, healthy body weight, and more.

Keep reading to learn about even more benefits of intermittent fasting.

6 Benefits of Intermittent Fasting

Here are six of the top intermittent fasting benefits you should know about.

“Is intermittent fasting good for weight loss?” It’s a common question I receive—and with good reason. I’ve found that intermittent fasting is more beneficial for healthy weight management when used in conjunction with a keto diet. 

Here’s why: When you eat a very high-fat diet, such as the keto diet, or fast for at least 12 hours, your body switches from primarily burning glucose (sugar) as fuel to burning ketones (fat) as fuel.

When digging into the science, the benefits of both a keto diet and intermittent fasting can look very similar. Both not only support metabolic health but also help to support healthy weight management, which is a particular benefit that many women are searching for.

Here is the piece that I find truly astounding and the reason why keto and intermittent fasting for women are so complementary: Being in ketosis prior to fasting can make fasting a lot easier, and fasting can help support the transition into ketosis. It doesn’t have to be one or the other, but you can use both tools strategically for your personal needs.

2. Supports autophagy

Remember, autophagy is your body’s cellular self-cleansing process. You can also think of it as the body’s own way of taking out the trash. 

During the process of autophagy, the body not only detoxifies but also supports immune function, cardiovascular health, longevity, and more.

Now, the trick is that autophagy can only be activated when the digestive system is turned off—and that’s where intermittent fasting enters into the equation. According to research, your brain responds to short-term food restriction by increasing autophagy. That’s why skipping breakfast might just be one of the best things you can do to activate autophagy and support whole-body health!

3. Promotes diverse gut bacteria

Intermittent fasting can also increase the diversity of bacteria in your gut, which is important for your immune and overall health. In fact, researchers have linked daily fasting to the activation of the gene that strengthens the gut barrier to protect you from harmful microbes, toxins, and other substances that can trigger immune reactions.

In addition, intermittent fasting helps to restore the integrity of the intestinal lining, favorably influencing the inflammatory response linked to the development of many chronic diseases. 

4. Supports healthy insulin and blood sugar levels

High blood sugar, whether in a diabetic range or not, is correlated with brain shrinkage over several years—the one place you don’t want to lose weight! By supporting healthy blood sugar levels and insulin sensitivity, intermittent fasting has been shown to help reduce brain cell damage stemming from glucose (glycation). 

Additionally, blood sugar control in middle-age can predict elderly disease risk—so today is the day to act and consider adding the practice of intermittent fasting to your eating habits.

5. Aids healthy digestion

Another one of the major intermittent fasting benefits is that it gives your digestive system a rest. Remember, your digestive system is the largest system in the human body, and if you’re eating eight small meals a day, your digestive system is constantly at work.   

Here’s why that matters: If your body is always digesting food, it doesn’t leave much time to work on anything else. It has little room to perform all of the other functions such as resting, building, repairing, restoring, and getting rid of toxic cells in the body. 

6. May support brain health

Simply put, the more blood flows to your brain, the more nutrition it receives and the better you can perform. Interestingly, research has shown that intermittent fasting helped to reduce brain inflammation in animals and may help protect neurons from both memory deficits and inflammation due to both infection and chemical damage to the hippocampus. (The hippocampus is the part of the brain that controls learning and memory.) 

Intermittent Fasting Schedule & Types

If you’re looking for an intermittent fasting schedule that will work best for you, there are a few options to choose from.

First, remember that intermittent fasting isn’t a diet; it’s a practice. While it complements keto rather nicely, it truly can be incorporated into any dietary philosophy, making it a helpful step as you work on implementing a keto diet, modified keto diet, or another whole food lifestyle approach.

When it comes to intermittent fasting for women, it is helpful to see that different intermittent fasting times and schedules work for different people. And, actually, it is very important to note that what works for you right now will likely ebb and flow throughout your life, so the less you can be attached to one “right” way to fast, or to keto for that matter, the better.

Earlier, I talked about how the 16/8 is the most common schedule for intermittent fasting, but other protocols work as well. Some start slowly with 12/12 or 14/10 while others find they feel best with a longer fast such as 18/6. 

Some people may even choose a one-meal-per-day approach and then fast for the 23 hours before their next meal. When restricting food to just one meal, or even two, it takes some careful consideration to make sure you are getting enough food and enough nutrients, especially if these restrictions are happening daily. So be sure to speak with your physician before trying this protocol.

And although some people will intermittent fast daily, others, especially women looking to do intermittent fasting for weight loss, may find that alternate day fasting provides just enough benefit without being too stressful on the body. 

With so many options, there are many ways you can incorporate intermittent fasting into your weight loss strategy. When it doesn’t seem to work anymore, you can mix it up and give your body a new rhythm to adapt to.

Just keep in mind that sometimes less is more. If you desire more weight loss or weight loss has slowed, you might be tempted to fast more and more, but that extra restriction may not always produce the desired results. It is about finding your sweet spot with fasting—where you look and feel your best and where your body naturally moves to your optimal weight.

What to Eat During Intermittent Fasting

Finally, there are a few more common questions that arise when someone is interested in trying intermittent fasting: Does intermittent fasting work, and can you eat anything while intermittent fasting? 

I’ve found that the answers to these questions go hand-in-hand. Yes, intermittent fasting does work—when you follow a healthy diet during your eating window. And this only begs the question about what to eat during intermittent fasting.

Because they are so well aligned, I always recommend following a high fiber keto diet while practicing intermittent fasting. But, as I noted above, intermittent fasting works well with any whole foods-based eating protocol. Just try your best to avoid inflammatory high sugar and processed foods, which will only undo the work you’ve put in by beginning your intermittent fasting journey.