Written by Dr. Inez Van Roy on
November 19, 2021
Reading Time: 6 minutes

Medically Reviewed by our Medical Affairs Team

Written by Dr. Inez Van Roy on:

Intermittent fasting mental clarity is in a lot of talks nowadays. 

Intermittent fasting is used mainly to lose excess weight as the rules are easy to remember and maintain. Many people don’t eat late at night and skip breakfast.

Today, people are also looking at intermittent fasting for mental clarity. What are the facts here and does it work? Are there any other possible advantages to using intermittent fasting?

Keep reading to know the answers.

What is intermittent fasting? 

Intermittent fasting is a technique to lose weight that limits the time in which someone can eat.

Usually, it is combined with eliminating refined carbohydrates and fructose. It focuses on excluding preservatives or processed foods.

You can choose to eat lean protein, healthy fats, and complex carbohydrates where needed. 

In short, people choose food deprivation. Eating like this is supposed to promote ketosis. In other words, your body uses fat as an energy source (as there is no sugar to use). This should lead to weight loss.

However, ketosis can also be obtained by eating a keto diet. Many forms of intermittent fasting don’t restrict fluids.

Many times schedules define intermittent fasting. You can fast 12, 16, 20, or 23 hours per day. Some also fast only one or two days a week. Most popular forms provide a big eating window and don’t eat breakfast.

They only eat dinner and lunch, or one big meal. Another popular form of this diet is alternate day fasting, food intake is only every other day.

How you fast, will depend on your lifestyle. It is recommended to start with fasting for a few hours as possible and to ask a professional for guidance. 

Fasting is not recommended for those with diabetes, pregnancies, lactating, or minors. Those with (suspected) eating disorders aren’t advised to follow these plans either.

Time-restricted eating could promote food deprivation of certain food groups. It could harm those with eating disorders.

Does intermittent fasting help with mental clarity?

Does fasting affect learning and memory? Dietary restrictions and/or intermittent fasting can have a positive effect on brain health. If you are a healthy adult, you might not get the results you are hoping for.

But if you are overweight, old, or struck by any neurodegenerative disease, you might see a positive effect. For those who want to try, they might want to consult a health professional.

Mental clarity is difficult to define. However, some might associate it with aging or stress. If that is your case, then an intermittent fasting diet might help your cognitive function. 

It is shown to prevent neuroinflammation and oxidative stress. Dietary restrictions are also shown to delay neurodegenerative diseases, like Alzheimer’s disease. 

In contrast, eating a high-fat diet could be the cause of your decline in mental clarity. It could be the reason your short-term memory is not necessarily working how you want it to.

So, it is clear that only fasting is not enough. We should also still choose food that supports our system (e.g., a low carbohydrate diet or less inflammatory foods).

Is intermittent fasting good for mental health?

Intermittent fasting could have potential benefits for mental health. People report more irritability. In contrast, they also report less worrying, more control, reward, pride, and achievement.

These people might have been focused on losing weight and felt the effects of obtaining their goal. Further, there are also reports that people have less anxiety and depression as a result of intermittent fasting.

Overall, it seems like intermittent fasting can have positive effects on mental health.

Fasting and Brain Health

Acute fasting might improve memory. In mice, there seemed to be a reduction of caspase-1. This is associated with anxiety, object location recognition, and increased object novelty. 

Research shows that caspase-1 is mostly high in overfed mice. Those on high-fat diets seemed to have the hardest time regulating these levels (and their inflammatory levels). As such, they experience more adverse effects. 

This seems congruent with comorbidity for humans with obesity and anxiety for example. These effects might be related to the survival mechanisms triggered by the fast.

Better memory and less anxiety might be critical in real life for the mice to find food and maintain good form while searching. 

If this were to be a survival method, your body would need to perceive an acute drop of energy (or lose weight) as significant enough to react like this.

Fasting Emotional Effects

Fasting is known to have positive and negative effects on our emotions.

Research shows that people feel more irritable. That might be what some refer to as “hangry”, not real anger but the plummeting of your blood sugar, or the feeling of running on a low battery. In short, they were hungry and fasting became increasingly difficult. 

The same researchers also observed positive effects on women. Women reported more sense of reward, achievement, pride, and control.

We read and hear everywhere that intermittent fasting can improve mood, and maybe that is the case. It does not have any superpowers though. What possibly explains this effect is the sense of control over their health or weight that people are reporting.

People report worrying less about their food intake or their meals when they limit the number of meals or time in which they do eat.

How long to fast for mental clarity?

It is not clear how long you should fast to obtain positive results for mental clarity. Most studies use an alternate-day fasting regimen.

In those cases, the test subject can eat for an entire day, and the next day they are restricted in eating, and so on. There are also other ways to fast as described above.

We still don’t know what would be the best outcome to use fasting in our daily life. This might depend on your sex, age, disease status, and more.

Further, it would be important to decide for yourself whether fasting has the desired effect on your quality of life. It might have a negative influence on social behavior, mood, and so on.

If you experience the negative effects of fasting, it might be wise to stop fasting. You can still choose to follow a healthy diet or to include other health interventions to improve mental clarity.

Can Intermittent fasting lower anxiety and depression?

There is proof that it may have positive effects for some people. 

The gut-brain axis theory attracts a lot of attention in the scientific community, and outside of the community. 

The idea that we can regulate anxiety, depression, and more by what we eat or don’t eat feels right. In the 90s and 2000s, the research couldn’t find consistent positive results from fasting on anxiety or depression.

Today, the public is retaking these practices. They are reporting higher levels of psychological well-being. 

A French meta-analysis and review seem to confirm the sentiment of the public. They found lower levels of anxiety, depression, and a lower body mass index, without increased fatigue.

It is not clear whether these effects are mostly due to calory restrictions, or due to fasting. Studies in mice appear to support these results.

Intermittent Fasting Mental Clarity Benefits

Intermittent fasting could be good for your metabolic health. It makes our body switch in how we use energy. Instead of using glucose, we will use stored lipids.

This “metabolic switching” happens after 12 to 36 hours after beginning your fast. This switch is associated with fewer neurological diseases.

It might also stimulate the removal or recycling of dysfunctional or damaged components. It also could protect against oxidative stress.

Further many forms of intermittent fasting follow the circadian clock. This natural system is known for regulating our sleep, mood and so much more.

Lastly, it could also support your gut microbiome. Supporting your system and body to function well.

Why do I feel mentally clear when fasting?

It is not clear yet what the exact mechanisms are that interplay. Many changes are happening in our bodies when fasting.

It might refer to getting rid of toxins or brain cells that are damaged or due to creating new functioning ones. Further, there might be a combination of chemicals, as explained above, that could be the cause.

How do you maintain mental clarity or at least reduce brain fog while fasting?

We don’t know how long you should fast to maintain (or gain) mental clarity. 

At this point, there are studies on humans and rodents. Mostly the studies on rodents are positive. 

In contrast, there are no long-term trials on humans yet. So, it could be that an intermittent fasting diet does more harm than good. 

What we do know is that certain effects seem similar to the positive effects of exercise. Until we know more, it might be safer to go for a run to get similar effects.

If you are experiencing more brain fog while fasting then you could consider quitting the fast. There are other (more researched ways) to optimize your mental clarity.

Concluding Thoughts

Intermittent fasting can be an easy health intervention for those who are overweight and want to work on their mental clarity. It is not the goal to starve yourself but to limit the amount of time in which we eat.

Further, certain foods are also avoided to support digestion and avoid inflammation. While the effect of losing weight is well established, it might be that you don’t feel different regarding any cognitive function.

Some people also report health effects on their mental well-being. You might feel less anxious or depressed. 

While all these effects sound wonderful, researchers don’t find these effects consistently. So the way you choose to fast (your health status) might have a direct impact on your results. 

It might also not be the safest way to achieve these goals. Other health interventions show similar results and are better-researched (e.g., exercise).

Want to learn more about how to achieve mental clarity and maintain overall brain health? Check out these helpful resources and feel free to join this community of mental health enthusiasts!

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