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The Complete Guide to Intermittent Fasting for Cognitive Benefits & Beyond


Intermittent energy restriction (IER) involves intermittently limiting energy intake levels.  There are many ways to restrict calories, one method involves limiting your calorie intake to about 500 kcal a day for days to three days a week. In another method, you must consume all your daily food within an 8 hour window every day, the last way is to simply fast for 24 to 36 hours without any food. In this article, I will discuss if there is any evidence that states cognition is improved via fasting and any other interesting thing I found while doing my research that you may like as well. Let’s start by getting to know some terminology so the article makes much more sense for you.

Table of Contents
1. Key Terms & Differences
2. How It Works
3. Overall Benefits of IF
4. Results Breakdown
5. Dealing with the onset of Hunger & Brain Fog
6. Disclaimer Clauses
7. Another form of IF, BulletProof
8. Closing Thoughts

Key Terms & Differences

Intermittent fasting (IF) may sound technical. But all it really means is going for extended periods without eating anything if possible. Throughout the world tribes experience one form of IF or another. Among them, many show no signs of age-associated problems like diabetes, cancer, neurodegeneration,  cardiovascular disease, or hypertension.

Caloric restriction (CR), researchers define caloric restriction as reducing food intake while avoiding malnutrition. In animal studies, this usually means consuming 30-40% fewer calories than the standard daily requirement. That’s the equivalent of limiting daily intake to around 1,200 calories for women and 1,400 for men. CR is very different for men and women, which I explain more about below. CR has prolonged life in dogs, rodents, worms, flies, yeast,  bugs, and non-human primates by 30 to 50% (evidence below).

Alternate Day Fasts Alternative day fasting (ADF), as the name implies you do this every other day or Every other day Fast (EODF).

24 Hour Fasts, done few times a week to achieve the same results, may be more difficult for beginners.

16/8 Fasts (Time Restricted Feeding) is what we will be discussing when referring to IF below.

How It Works

  • The best way to begin fasting is by giving your body 12 to 16 hours between dinner and breakfast every single day. This allows 4 hours to complete digestion and 8 hours for the liver to complete its detoxification cycle.
  • That mean’s give yourself eight hours or more of ‘feeding time’. The rest is a no ‘feed zone’.
  • Tip: Have Plenty of Water, Skipping breakfast is a simple way to do IF. Many people do IF to go into Ketosis (fat burning mode) to shed fat and get your brain running on ketones for energy (This actually takes a few weeks for your body to get use to.)

Ketosis is characterized by raised levels of ketone bodies in the blood/body associated with fat metabolism. Meaning you are obtaining your energy from fat rather then glycogen (think carbs). The brain prefers to run on fat (via ketone bodies) , these energy molecules become fuel for our brains after being converted from fat by the liver. This can only happen when insulin your bloodstream is low, the lower it is the higher the ketone production. You can be in different levels of Ketosis but scientifically if you are at 1.5 – 3 mmol/L it is considered the optimal state but from a nutritional standpoint 0.5-1.5mmol/L is considered good enough.

Benefits to the Brain from Intermittent Fasting

Brain health is very much dependent on neuronal autophagy (the act of self eating, this is when cells recycle waste and repair themselves). Without the process of autophagy, brains do not develop properly and function as intended.  Take a look at the results of the study: Energy intake, meal frequency, and health: a neurobiological perspective. The results state:

In humans, excessive energy intake is associated with increased incidence of cardiovascular disease, diabetes, and certain cancers and is a major cause of disability and death in industrialized countries. On the other hand, the influence of meal frequency on human health and longevity is unclear.

Both caloric (energy) restriction (CR) and reduced meal frequency/intermittent fasting can suppress the development of various diseases and can increase life span in rodents by mechanisms involving reduced oxidative damage and increased stress resistance.

Many of the beneficial effects of CR and fasting appear to be mediated by the nervous system. For example, intermittent fasting results in increased production of brain-derived neurotrophic factor (BDNF), which increases the resistance of neurons in the brain to dysfunction and degeneration in animal models of neurodegenerative disorders; BDNF signaling may also mediate beneficial effects of intermittent fasting on glucose regulation and cardiovascular function.

So basically, there is a increase in BDNF, but since the study was not conducted on humans, we can’t definitively state that it can increase human lifespan or overall health. BDNF is a protein that interacts with neurons in the hippocampus, responsible for regulating memory and learning. It helps neurons survive and grow new neurons via neurogenesis and increases the development of synapses between neurons.  Sounds like something those looking to keep their brain healthy and functioning optimally may want. Being low on this stuff has been linked to many diseases such as Alzheimer’s. BDNF is naturally occurring and has been extensively tested on mice and in each case it has shown to significantly improve the learning capacity, working memory (Working memory is how many pieces of information you can juggle in your mind at any given time) and cell signalling [reference].

Other Benefits:

  1. Lose Weight (Shed Fat) – Easier to maintain low body fat, via insulin sensitivity for skeletal muscles. Might be better, burning fat, using fat rather then carbohydrate.
  2. Longevity (Mediated mostly by AMPK pathways). Helps deplete damaged mitochondria and is anti-inflammatory, although not proven definitively.
  3. Blood Pressure Regulation
  4. Bodybuilding – Increase mTOR.
  5. Increased Growth Hormone – Fasting for more than 6 hours begins the cleansing phase.  The cleansing phase is catabolic in nature in that it tears down old damaged cells.  These genetic repair mechanisms are turned on through the release of human growth hormone (HGH). HGH also improves skin function, reduces wrinkles & heals cuts and burns faster. Researchers at the Intermountain Medical Center Heart Institute found that men, who had fasted for 24 hours, had a 2000% increase in circulating HGH. Women who were tested had a 1300% increase in HGH.
  6. Save Time (and money?) in the morning
  7. For Epilepsy – Decreased, Normal brains, when overfed, can experience another kind of uncontrolled excitation, impairing the brain’s function, Mattson and another researcher reported in January in the journal Nature Reviews Neuroscience.”(source)

Breakdown of Results on Cognition from IF

When it comes to IF and the it’s benefits, I repeatedly came across the name Mark Mattson. Mark Mattson (a neurologist at Johns Hopkins University and the National Institute of Health (NIH) research is cited in most if not all ‘important’ papers discussing IF online. His research states (in short): Fasting reduces oxidative stress, cognitive decline and mitochondrial dysfunction that normally results from brain trauma, so when researches put rats on a 24 hour fast it proved to provide neuroprotective results.

This study discusses how Human (and non-human) studies show that IER increases synaptic plasticity (marker of learning and memory), enhances performance on memory tests in the elderly, leads to the growth of new neurons, decreases risk for neurodegenerative diseases.

  1. GeoMetric Memory – Worse
  2. Spatial MemoryLack of effect
  3. Reaction Time – Increased
  4. Processing Speed – Decreased
  5. Psychomotor abilities – Improved (Psychomotor abilities is the ability to manipulate and control physical objects.). Study on mice and rats, results seen when rats reached Ketosis. Key take aways from this study you may find interesting:
    1. With EODF implemented after rat cervical spinal cord injury was neuroprotective, promoted plasticity, and improved behavioral recovery. Without causing weight loss, EODF improved gait-pattern, forelimb function during ladder-crossing, and vertical exploration. In agreement, EODF preserved neuronal integrity, dramatically reduced lesion volume by >50%, and increased sprouting of corticospinal axons. As expected, blood beta-hydroxybutyrate levels, a ketone known to be neuroprotective, were increased by 2-3 fold on the fasting days.
    2. In addition, we found increased ratios of full-length to truncated trkB (receptor for brain-derived neurotrophic factor) in the spinal cord by 2-6 folds at both 5 days (lesion site) and 3 weeks after injury (caudal to lesion site) which may further enhance neuroprotection and plasticity.
  6. Depression – Decreased – Anti depressants are known to increase BND signaling and synthesis in the hippocampus. Most of the studies have been done on rodents but it is plausible that intermittent fasting may help alleviate depression to an extent.

Dealing with Brain Fog & Hunger


To reduce “brain fog” (Brain fog may be described as feelings of mental confusion or lack of mental clarity. While on the diet, there are two options, one is to have a low calorie drink (less than 50kcal, if your energy level is dropping and ketone energy just isn’t doing it for you, and consume it with nootropics which may potentially help with brain fog.) Consume water. Keep in mind the mind-numbing hunger feeling subsides over time, in up to 6 weeks (on 5:2 diet — 5 days off, 2 days on with CR).

Supplements & Drugs that May Help

If you are trying IF and just feel like your brain fog is not subsiding, and you are just feeling too drained, you may want to consider taking supplements that may help, some can think it is a form of cheating, but it is up to you to decide if you want to go this route.

First one would be a drug called Modafinil will suppress your diet and provide you the mild CNS stimulation you may need to ‘get work done’. I will leave you to check out the link to learn more about this one, and its similar compounds like Adrafinil or Armodafinil (Provigil).

Number two is taking nootropics such as Phenylpiracetam, Caffeine (pill, and definitely not with sugar and creamer or milk!), one will give you a jolt of energy and the other will keep your brain focused. Some people on reddit and around the web have provided anecdotal evidence of ALCAR being effective to stave off hunger, other’s have even recommended a herbal tea’s known as Kratom.


Note on these supplements: The benefits should be worth your time and counteract any negatives.

As for women: Research has stated that in the long run, IF can disregulate a women’s reproductive system, but these aren’t conclusive. If you are a women, you should listen to your body and tread carefully, also watching out for signs of hypothryoidism and amenorrhea.

Bulletproof Intermittent Fasting

A new type of fast, since we are fans of Bulletproof we are mentioning it here. You could try another coffee company and any other MCT Oil (or better) just make sure you consume the right one (as described in the video). Bulletproof has been known to be somewhat of a “reliable source” for us and that is why it is being recommended and we do get referral fee if you use the link below (with no added cost to you!).


  1. 8:00 AM: Drink Bulletproof Coffee.
  2. 2:00 PM: Break fast with foods from the Bulletproof Diet.
  3. 8:00 PM: Eat your last meal before beginning the fast.

What You Need (click to buy):

  1. Bulletproof Coffee – Said to be very low in mycotoxins and considered a premium coffee.
  2. Brain Octane Oil (18X of MCT) or MCT Oil – Ketone Energy
  3. Grass Fed Butter – Anchor brand works and use very low amounts.

My take: Although not a real fast to get your body running on ketones, this does get’s you into a mild ketosis, and maybe more ‘practical’ for most people, but needs more research. However it is simple enough to try and many communities online swear by it.

Closing Thoughts

  • Most fasters do allow themselves coffee, teas and other non-caloric beverages during the fasting. Generally acknowledged that drinking a beverage with fewer than 50 calories will keep you in a fasting state.
  • Many do not claim to really notice an increase in ability to comprehend data faster, but many have reported the ability to focus and pay attention better when on IF. (Reddit)
  • Anecdotal Evidence by members of “The fast Diet” 5:2 diet however state that they noticed up to a 50% improvement in memory. For both of these we don’t know if the member’s have any sort of memory problems, and of other confounding variables.

Additional Tools

TrackMyStack (TMS) – If you want to really try Intermittent Fasting and want a measurable way to record your general health (and performance, or ODL’s) consider using a Stack Journal to do so.  You can’t see what’s working and what’s not if you are not actively quantifying your mood, side effects, anxiety etc and we are the perfect platform to do so. I have a journal which I have been using for the past month and it shows me that I have been able to put off eating for longer amounts of time because now based on my diet, I feel satiated for longer amounts of time and my mood is generally better as well. It’s not just me that is tracking this stuff, check out this super in-depth stack of a user trying to increase BDNF.

I wish you the best of luck, IF is something anyone can try and play around with without harming themselves too much (or needing much to start). Remember, there are many types of fasts that can be undertaken if one does not fit to your liking. You may will experience grumpiness and headaches at first, but with some will power it can be overcome.

Most studies as referenced to, do link to non-humans trials but some have been tested on humans and the results are somewhat similar. The supplements mentioned above and Bulletproof intermittent fasting are some ways people cope and try out IF and you are welcome to try them (but I recommend only do so after you have attempted ‘regular’ IF.). Go ahead and get started, create a TMS account and track your progress towards better health cognitive health.

– TrackMyStack Editorial Staff
Jeff & Asher