Intermittent Fasting: Try This at Home for Brain Health

If you’re a regular listener to the CLB podcast, you’ll hear me, in our next episode (coming soon!) discussing the latest neuroscience research on intermittent energy restriction (IER). IER, as the name implies, involves intermittently restricting energy intake, or calories. You can do this in several ways. In one method you severely restrict calories (think 400-500 total intake per day) two to three days a week; in another you confine your food intake to an 8-hour period every day; and in yet another you fast once a week for  a 24- to 36-hour period.

Sound intriguing? Difficult? Impossible? Read on . . .

The benefits of intermittent fasting for metabolic health are already pretty well established. In non-human animal models as well as in humans, IER leads to weight loss and reduced body fat; lowers blood pressure and resting heart rate; and improves risk markers for cancer, diabetes, and cardiovascular disease. This is true even when the faster’s overall calorie consumption is the same as a non-faster (because, for example, the faster consumes more calories during his non-fasting periods than he would otherwise). Just by giving yourself an occasional break from eating, then, you do your body a big favor, even if you don’t eat less overall.

But as described at a symposium held last November at the Society for Neuroscience’s annual meeting (a summary of which is published here), it’s becoming clear that the advantages of IER are even further reaching, with enormous implications for brain health. Human and non-human animal studies have shown that IER increases synaptic plasticity (a biological marker of learning and memory), enhances performance on memory tests in the eldery, leads to the growth of new neurons, promotes recovery after stroke or traumatic brain injury, decreases risk for neurodegenerative diseases like Alzheimer’s and Parkinson’s disease, and may improve quality of life and cognitive function for those already diagnosed with these diseases. IER has also been shown to play a preventative and therapeutic role in mood disorders like anxiety and depression.

The rewards of IER for metabolic and brain health are mediated by a number of complex biological mechanisms, but the underlying idea behind the science is simple: Periodically challenge your cells and biological systems (by food deprivation) in a controlled way, and these cells and systems will become stronger, more efficient, and better able to handle the daily stresses that come their way. It’s the same basic idea that underlies weight-training and other forms of exercise. We damage our muscles (a little bit) to build them up.

Trying at Home

Given the increasing scientific consensus and the huge potential payoff for brain and body health, I decided after recording our podcast that I had better put my money—or my empty fork— where my mouth is and give IER a try. Though the human IER studies report fasters complaining of initial side effects like grumpiness, headaches, and preoccupation with hunger, they also say that after about a month, most fasters adapt and learn to tolerate the fasting lifestyle pretty well. So, with this in mind, starting last November, I gave it a try.

8-on 16-off

The first method I attempted was the 8-on, 16-off method. For me, this meant no food beginning after dinner (about 8pm) for 16 hours. I could eat again at about noon the next day.

I tried this method for a week. I reported grumpiness, headaches, and preoccupation with hunger. The biggest problem with this method for me was that I’m a big breakfast eater. I like to wake up, work out, and eat . . . and the first two items on this list are a lot less motivating when the third isn’t there. Though I did get more used to the routine by the end of the week (I solved the headache problem by forcing myself to drink more water), the thought of going without breakfast every day made me depressed. And depression is not good for brain health.

24 hours

So I decided to try the weekly 24-hour fast instead. This way, I reasoned, I could get the fasting over with in one shot. I started in late November, and have been fasting once a week, dinner-to-dinner, since. I even managed to keep it up over the holidays.


Have I adapted to my new lifestyle? Well, yes and no. I don’t get headaches, I’m usually not too grumpy on fast days, and if I keep myself busy—I always fast on weekdays— I can usually get through the day without thinking too much about food (though when 5 o’clock comes around you might catch me googling recipes and daydreaming about what I’m going to make for dinner that night). But going without food for 24 hours is just hard, and it seems like it will continue to be hard no matter how many times I do it. I did it yesterday, for the 6th or 7th time. It was hard.

Despite the difficulty, though, over time I’ve experienced an unexpected reaction to my fasting routine. I’ve come, perversely, to enjoy it. And though psychologically, I don’t necessarily look forward to my fast days, physically, I do. It’s a feeling that’s hard to explain, but if you’re a regular exerciser you might understand an analogy: it’s similar to the desire you feel to get up and get moving after being sedentary for a long period.  And when I’m through with a fast, to continue the exercise analogy, I feel like I do after finishing a tough workout: spent, but happy. It’s this unexpected reaction, which, it turns out, is not unusual, that has convinced me that fasting is good for me.

So if you’re thinking about New Year’s resolutions for physical and mental health, I would recommend, based on the science and my own experience, giving IER a try. It can’t hurt if you’re smart about it, and it very likely will help you develop a stronger, healthier, body and brain. But don’t hold me responsible if, in the short term at least, grumpiness, headaches, or preoccupation with food ensue.

12 Responses to Intermittent Fasting: Try This at Home for Brain Health
  1. Pingback: Stanford Researches Brain Function Benefits of Intermittent Fasting - Intermittent Fasting News Daily

  2. Sounds like a promising way to lose weight! I might actually try this for brain health

  3. I started IER in January of 2014. I wanted to lose weight. And I did (38 lbs.)! I slacked off over the holidays ( gained 5 lbs.) but I have picked it back up ( already lost 3) and am feeling that great, hyperaware feeling that I get from this way of eating. I do the 5:2 diet. It works for me but it isn’t for everyone. There is nothing fast or “sexy” about it. Basically, you are eating less ( and ,hopefully, exercising more) and you WILL lose weight. I feel great….still feel great….one year later. This is not a fad. It’s a way of life.

  4. I enjoyed this article and found it informative and interesting. I google searched for “effects of fasting on the brain” and found this link. I read something recently on this topic and found it intriguing and decided to try it.

    This morning I had two cups of black coffee around 7:30 and have not eaten anything since having a Haagen Dazs ice cream bar after dinner around 9:30 p.m. I feel pretty good and was super busy at work and have not been too preoccupied with food or being hungry. It definitely helps to stay hydrated. I drank a large glass of water with a Emergency Vitamin C pack which has other nutrients and B vitamins.

  5. Not very happy with the article … So you gave up the breakfast but you just couldn’t move your 8 pm dinner (which is TOO late and plain stupid ) earlier to have an early lunch to motivate you during the rest of the day ? … just useless article …

  6. Why the name for a noble, effective, and extremely ancient health and spiritual practice has to be changed is a freaking mystery to me.

  7. I find the 5:2 method the most palatable; a supplement like green tea or turmeric can help curb hunger (I have joint pain so take them anyway). Still get the enhanced clarity/high for at least a few hours…though also can feel a bit spent. I like it and find eating 400-500 calories way more manageable than not eating for 24 hrs…

  8. This article was anything but useless. I found it quite valuable. You may not have appreciated it, but rather than expressing your opinion kindly and constructively, you chose to be mean and insulting. This says much more about you than it does about the article.

  9. Fasting is very beneficial as is the Ketogenic diet which mimics fasting without abstaining from food.

    They both work on the basis, i.e liver producing ketone bodies to breakdown fatty acids to make them water soluble to be transported in the blood. They pass the blood-brain barrier so are an incredibly efficient fuel source for the brain, even more-so than glucose. The brain prefers ketone bodies as a fuel source but still needs 10% glucose which, through the process of gluconeogenesis, gets it’s needed glucose supply without the need for dietary glucose i.e carbohydrates.

  10. Fantastic article. In fact the content is well backed by thousands and thousands of articles and data online. I love your posting this on your website which gives it credibility above and beyond posting it being put on social website for example. I have tried IER since May 2016 and went from 203 lbs to 187 lbs by November. Basically did the 8 on, 16 off method you mentioned above. Other than wanting to lose weight I am learning 2 instruments now for 5-6 years (violin and piano) as a 52 year old adult so the fact that IER helps new brain cells to grow is very important to my brain health and to my ability to learn music.

    The only time I avoid IER is the day after any major cardio and muscle building workouts. After a simple 400 calorie run yes could do IER but not after any weights or high heart-rate workouts. Plus I found IER before a workout did not give me enough energy for the workout. But other that that, IER has helped me get through the holidays where it is easy to put on a lot more weight. Plus it has toned my body.

    One interesting story that relates is that recently I heard a zoo does not feed their lions every day and when asked the zoo staff said the lions are only fed every 2-3 days. This makes sense and I wonder if the 3 meals a day we espouse is actually a myth and not realistic for our bodies.

    As well we recently had 2 Swiss technicians working at my plant here in Cambridge Ontario for about 1 week. They only ate 1 major meal a day. The other 2 meals were a coffee or tea and a small biscuit or piece of bread. And these gentlemen both cycle over 10,000km a year back home in Europe. They might not call it IER but they definitely are living that life style.

    One last note…if IER were to become more common amongst the general population, consider how much less food we would need to produce worldwide. Environmentally it would be a benefit for sure. Mind you, there would be a lot less restaurant capacity required so restaurants would not like that 🙂

  11. I’m doing 16:8 and it’s pretty much the best “diet” I’ve ever tried so far. I’m eating two meals a day, and when I eat I can eat until I’m full, so it doesn’t feel like a diet. I’ve lost 10 lbs so far and I’m feeling less depressed and stressed. Even if I stop losing weight, I’d probably stick with it as long as it helps with feeling depressed and stressed.

    I’m going to try a 24 hour fast this weekend. I’m going to eat a filling breakfast Saturday morning (I don’t eat breakfast normally, I eat in the afternoon/evening) and then fast until lunchtime Sunday. I’ll see how it goes, if it works and I don’t feel horrible that might become a weekend ritual.

  12. I just started the 16:8 from 8pm-12pm and I am loving the way I feel on a day-to-day and I haven’t experienced any grumpiness or depression. I do feel hungry around 9:30am most days BUT the feeling of hunger goes away after a glass of water or a black coffee. I work a 8-5 job and this diet is easy considering I no longer have to wake up early to prepare breakfast. I typically eat 3 semi-large meals a day, and I eat more frequently towards the end of my eating window. I am 5’6 and I started IF at 165lbs, 1 week later I am now 160lbs. I used to be an athlete and now I workout frequently in exception of this past week as I was focused on adjusting to my new eating routine.

    I also cut out all processed foods about a month ago and lost around 5lbs (170lbs to 165lbs) during that period and I felt way worse considering I was fighting an addiction to sugar/processed foods. I would recommend to anyone with strong cravings and a poor diet to start out by first cutting out all processed foods to end your toxic hunger pains associated with eating foods that cause inflammation, and then start intermittent fasting once you have corrected your eating habits.

    I plan to keep my 16:8 IF routine for as long as I see and feel the benefits. I hope to continue the trend of fat loss and get back to my once athletic frame!

    Thank you for the article! I loved the read and will show this to friends of mine with questions about IF 🙂

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