Back to Blog
How to Take Control of Your Cognitive Health Through Fasting

How to Take Control of Your Cognitive Health Through Fasting

Jun 16, 2023

Intermittent fasting offers a number of cognitive health benefits. Here’s a look at how to follow an intermittent fasting plan, and how fasting affects your body and brain.

Nutrition isn’t just about what you eat. It’s about when you eat.

That’s the idea behind intermittent fasting. You may have heard about fasting for its health benefits before; it’s been making the rounds in online health and fitness spheres. But the practice of fasting dates back centuries, spanning all kinds of regions and cultures. Today, let’s discuss how fasting impacts our bodies and brains, what its potential health benefits are, and how to incorporate intermittent fasting into your nutritional plan.

The science behind fasting

Fasting refers to a dedicated period of time during which you choose not to eat. Intermittent fasting specifically refers to developing an ongoing pattern of cycling through periods of eating and periods of fasting. 

We’ll dive into the different ways to structure an intermittent fasting plan soon. But for now, let’s take a look at what happens inside our bodies when we fast.

Fasting & our metabolism

When we eat, our bodies break down food into its base compounds and nutrients to sustain themselves. Carbohydrates, found in sugars and starches, are one of the most important of these compounds. Our bodies convert them into glucose, which is released into our bloodstream and used as the energy to keep us functioning. Glucose that isn’t immediately absorbed and converted into energy gets stored in our liver. After that, any excess carbs we eat are converted into fat instead - long term energy we tap into when we run out of immediate glucose energy.

Eating throughout our waking hours, or only going short amounts of time without food, means our bodies rely almost entirely on glucose energy for fuel. But when we fast, deplete our stores of glucose. This leads our bodies to resort to burning fat for energy instead. This metabolic process is called ketosis.

Fasting & cellular autophagy

Beyond its influence on our metabolism, fasting also affects our bodies on a cellular level. When you don’t provide your body’s cells with a steady stream of glucose to fuel them, you challenge those cells to function without it. They have to adapt to use energy more efficiently, and turn to other sources (like ketones) for fuel. 

Over time, cells and their individual parts can become worn down, defective, or even stop working entirely. So, our bodies have a natural recycling system known as autophagy. During autophagy, our bodies get rid of nonfunctional “junk” cell parts, disassembling cells to salvage the best parts and reassemble them into new, better functioning cells.

Autophagy occurs naturally, but adding stress to your cells - like by fasting - can also help induce autophagy. 

What are the health benefits of fasting?

Thanks to its influences on our metabolism and our cell performance, fasting has quite a few health benefits for both our bodies and brains, such as:

  • Weight loss due to decreased calorie consumption, better insulin management, and higher levels of Human Growth Hormone (HGH).
  • Improved heart health, including reduced blood pressure and cholesterol levels, better resting heart rates, and a resulting overall decreased risk for heart disease.
  • Improved cognitive performance, and in particular, improved working and verbal memory.
  • Reduced inflammation, which can improve conditions associated with inflammation such as arthritis and asthma.
  • Increased longevity and protection against disease, as fasting-induced autophagy changes gene function over time.
  • Decreased risk of Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative disorders, thanks to brain cell autophagy addressing damaged DNA and creating new neural pathways.
  • Decreased risk of cancer, as cell anomalies are more likely to be deconstructed and destroyed before tumors can form.
  • Improved resistance to cognitive decline, fostered by insulin sensitivity, reduced inflammation, increased circulation and optimized blood pressure, and addressing mitochondrial and other cell deficiencies.

Now that you understand how fasting works and the ways it can benefit your health, let’s look at how you can create and follow an intermittent fasting plan.

Developing an intermittent fasting plan

There are a few different approaches you can take when developing an intermittent fasting plan, but we strongly recommend daily time-restricted fasting.

Daily time-restricted fasting aims to limit your time eating in a way that aligns with your circadian rhythm. The idea here is that our body’s internal systems work best when aligned with one another. (And that alignment can be thrown off by things like late-night snacking.) In this approach, you will fast between certain times of day, usually for a period between 12 - 16 hours.

How to start daily time-restricted fasting

Establishing your fasting period

The most common daily time-restricted fasting schedule is the 16/8 approach: 16 hours of fasting, followed by 8 hours during which you can eat. For example, your eating cycle could fall between 10am and 6pm each day, meaning you fast from 6pm until 10am the following morning.

Depending on your medical background and your experience fasting, you may also want to begin a time-restricted fasting schedule with a shorter period of fasting, like 12 hours (fasting 8pm to 8am) or 14 hours (fasting 8pm to 10am). These schedules can be easier to start with because they align with our sleep/wake cycle.

You can also try easing into fasting by doing the 16/8 approach, but only once or twice a week to start. Then, you can increase the number of days you fast each week over time until you are fully committed to a 16/8 schedule.

Focusing on nutrition

During your eating periods, it’s important to nourish your body properly. This will ensure you optimize the health benefits of your fast, while also helping prevent you from feeling hungry or sick when you’re not eating. Start by focusing on these four nutritional areas:

  • Lowering carbs - Eating fewer carbohydrates and refined sugars will help you go longer without eating, while feeling less hungry. It will also help you avoid energy spikes and crashes, and reduce inflammation that can harm your brain.
  • Increasing vegetables - Vegetables contain vitamins, minerals, and fiber which nourish our bodies and help us go longer without eating. Try to eat a wide variety of vegetables - all the colors of the rainbow.
  • Consuming lean proteins - Lean proteins like fish and chicken will help you feel full longer. Non-meat proteins, like beans and lentils, are also a good choice.
  • Focusing on healthy fats - Healthy fats - like the kinds found in nuts and avocados - also help you feel full while providing longer-lasting energy.

Most importantly, have these nutritional foods on-hand when you’re ready to break your fast each day. (When we’re hungry, we’re more likely to choose unhealthy meals.) You can also consume water, tea, and coffee - without any milk, sugar, or other add-ons - during your fasting period.

What if I get hungry while fasting? 

Feeling hungry is normal when you first begin intermittent fasting. Your body needs time to adjust to your eating schedule, and to burning ketones for energy.

If you need a snack during your fast, stick to healthy fats like nuts (unsalted/unflavored) or avocados. Remember, as time goes on and your body adjusts to fasting, you will begin to feel less hungry while going longer without eating.

Plan Ahead

Although it may seem simple to eat healthy, it takes some planning in the beginning. Changing your eating habits and your tastebuds can take time. We recommend you research some tasty and healthy recipes before you start fasting. Make sure you go grocery shopping prior to starting your fast and prepare your healthy meals ahead of time. 

Waiting till the last minute to prepare your food can lead to binge eating. It can also lead to opting for high calorie high carbohydrate foods, since your brain might be signaling you to eat anything at all costs.


One of the key ingredients to succeeding in fasting is to take things slow and to surround yourself with a support system. It could be a partner who is also fasting with you. It could be a friend, who also decided to change their life around and start eating healthy as well. 

There are also a lot of online support groups. Choose the style of support that most resonates with you, and have fun. This is an adventure! 

Other approaches to intermittent fasting

Though we recommend time-restricted fasting for most individuals, here are a few other approaches to intermittent fasting that can be beneficial to your health:

Alternate day fasting:  An alternate day fasting approach means eating normally one day, and then doing a full or partial fast the following day. (A full fast would mean eating nothing, while a partial or small fast means sticking to a single small meal, usually 500 calories or less.)

5:2 fasting: A 5:2 fasting approach divides your week between five days of normal eating and two days of partial fasting (eating about 500 calories).

Fasting fad diets to skip

While daily time-restricted fasting, alternate day fasting, and 5:2 fasting can positively impact your health, not all intermittent fasting approaches are equally beneficial. Here are a few popular diet plans involving intermittent fasting we recommend skipping.

Eat Stop Eat fasting

What it is: The Eat Stop Eat approach to fasting involves doing a full 24-hour fast once or twice a week. The rest of the week, you eat normally. People may find this approach appealing because like 5:2 fasting, it means you only have to think about fasting once or twice a week.

Why you should skip it: A once-weekly fast typically doesn’t trigger the same metabolic or cellular benefits of a more regular intermittent fasting cycle. Research shows that the time it takes people to enter ketosis varies, so a single 24-hour fast may not have a lasting enough effect on your body. Similarly, it would not add the recurring stress to your cells necessary to continuously trigger autophagy. Put simply, it’s just not the most effective or beneficial approach to intermittent fasting. Plus, a longer fasting period (a full 24 hours) means you will likely experience more severe side effects, including increased hunger, irritability, headaches, insomnia, and more.

Try instead: If the idea of fasting regularly but for less time is appealing to you, we recommend trying a shorter period of time-restricted fasting. A 12- or 14-hour fasting period will help mimic your sleep/wake cycle, helping you to feel less hungry..

The Warrior Diet

What it is: The Warrior Diet is a variation on daily time-restricted fasting, where people fast for 20 hours and eat for 4 hours each day. During the 20-hour fasting period, you may consume some raw fruits and vegetables and small amounts of dairy products. This “undereating” phase then leads into 4 hours a day of “overeating” where you can consume other foods.

Why you should skip it: The structure of the Warrior Diet easily lends itself to unhealthy binge-eating; the severe restrictions increase the likelihood you’ll overindulge during your eating period, which diminishes any weight loss and metabolic benefits you may receive from fasting. Its emphasis on “overeating” versus “undereating” can also foster feelings of regret and shame about food, and might increase the risk of developing disordered eating habits

Try instead: If the idea of fasting for certain hours each day appeals to you, we recommend trying the 16/8 method instead.

Additional considerations when fasting

Fasting may seem like a straightforward decision between choosing when to eat and when not to eat. However, like all significant changes to your lifestyle, there are some other considerations to keep in mind. Here are a few additional factors to be aware of, to ensure you’re fasting safely and in the way most beneficial to your health.

Fasting side effects

The biggest side effect of fasting is (you guessed it) hunger, as you adjust to going longer periods without food. Other common side effects include fatigue, irritability, difficulty concentrating, and headaches. Generally, these symptoms disappear over time as your body adjusts to your new eating/fasting schedule; many people say side effects from fasting disappear after the first month. Remember you are re-conditioning your body to years of unhealthy eating habits and it may take time for your body to adapt. 

Though fasting adds intentional stress to your body, it should not make you feel severely ill. If fasting becomes physically painful, you feel too sick to carry out day-to-day activities, or you feel like you might pass out, stop fasting and consult your doctor. You may want to consider shorter fasting periods to start with and focus on developing healthier eating habits. As time goes on, you can increase your time restriction by 15 minute increments.

General nutrition

On its own, fasting only dictates when you eat, and does not itself suggest guidelines as to what you should eat during your non-fasting hours. 

However, consuming only junk food isn’t advisable for anyone trying to stay healthy, or anyone who wants to optimize the potential benefits of fasting. Your non-fasting periods should be spent consuming nutritionally balanced foods, full of protein, leafy greens, and healthy fats. Fasting is not a substitute for a nutrition plan; it’s one part of a whole approach to your health.

Risk of binge eating

On a similar note, people who are unaccustomed to going for longer stretches without eating may find fasting challenging at first. If you only eat when you are very hungry, you have a higher risk of binge-eating - consuming too much too fast, and often of foods with little nutritional value.

If you feel like you can’t help but overeat after a fasting period, try shortening the length of your fast or doing a partial fast instead. You can always return to a full fast or lengthen the time of your fast as your body adjusts. The bottom line is fasting should make you feel more in control of your diet and nutrition, not less.

Exercise & physical activity

Physical activity is an important part of a healthy lifestyle. However, people who are fasting need to be careful that exercising does not place too much added stress on their bodies. Especially when you are fairly new to fasting, make sure to keep your workout intensity and duration fairly low and always stay hydrated. It may take you some time and trial-and-error to determine whether exercising before, after, or during your fasting period works best for your body. Remember, if you feel dizzy or weak, listen to your body and take a break from activity.

Take control of your meals and your cognitive health

Fasting promotes metabolic flexibility and cellular autophagy, which in turn can have innumerable health benefits for your body and brain. Ultimately, choosing to fast isn’t just about choosing when to eat. It’s about making a choice to be a more active participant in how your body uses and processes nutrition.

While intermittent fasting is safe for most adults, it can be unsafe or unhealthy for others, such as people with diabetes, people with a history of eating disorders, and people who are underweight. Always consult your doctor before making any significant changes to your diet and eating habits.

Better nutrition, better brain

Are you looking to revolutionize your nutrition, change your lifestyle, and optimize your cognitive health? If you know it’s time to not just work around your health challenges, but to do something about them, check out NeuroFlow Foundations. We’ll send you new tips and tricks for improving your cognitive health each month, all backed by our years of medical expertise and grounded in our holistic six pillar approach.


Learn more about NeuroFlow Foundations