The Eades also wrote about the idea a couple of years ago and recently there have been several inspiring "transformation" stories on the internet of people who have adopted IF and seen some great changes in their physique: Richard and Keith (see photo to the right) are inspirational.
All this material led me to study the idea of IF and it is now something I often practice. Martin Berkhan has taught me a lot, but the writer whose work I have found most helpful has been Brad Pilon.
His book Eat Stop Eat is an easy read but goes into a lot of detail examining the science behind IF and exploding some of the associated myths - e.g. it is not true that fasting will send your body into "starvation mode" and slow your metabolism.
This week Brad agreed to do an interview with me. I think his answers to my questions are really helpful and interesting and expand on some of the ideas in his book.
Can you tell us something about yourself. How did you first develop your interest in health and fitness and where did it lead?
I think to a degree I have always been interested in health and fitness. I had a subscriptions to the American Journal of Clinical Nutrition when I was 16. I did my ‘tour of duty’ working in a supplement shop during high school. I’ve been a ‘gym rat’ since I was 8 or 9. Food, nutrition and weight training have always been an interest for as long as I can remember.
You have become particularly well known for your book "Eat Stop Eat" which looks at the science behind intermittent fasting. What initially prompted your interest in intermittent fasting? Where did you first come across the idea?
Originally I had no interest in fasting. It wasn’t until I started doing my master’s research that I ended up realizing there was merit in the concept. My intention was simply to study nutrition and weight loss...so I wanted to start with fasting as kind of my base point. Once I established all the bad things that would occur when someone fasted, I would build up from there...turns out that wasn’t the case..and once I started realizing that most of what we knew about fasting was incorrect, I was hooked.
A lot of writers on sports nutrition make a big deal about "peri-workout nutrition" - eating "correctly" in the pre and post workout periods? However lots of us work out fasted and seem to perform well. What is your take on this debate? Does it really matter?
I am very conflicted on post-workout nutrition. Firstly as I point out in my new book “How Much Protein?” there is actually very little DIRECT evidence for post workout nutrition that was not funded by either a supplement company or some form of a protein-food group (like the egg board). From my experience, research showing ‘remarkable’ muscle building effects of protein have never been reproduced in a study NOT funded by industry. Secondly, many of the surrogate endpoints that are studied (such as nitrogen balance and protein synthesis) have never been causally linked to muscle growth, so our actual true evidence that peri-workout nutrition effects muscle growth is very limited.
There is currently quite a movement towards eating and moving like our hunter gatherer ancestors - Evolutionary Fitness or the Primal Blueprint or whatever people like to call it. This template is interpreted differently by different people, but periods of fasting are often an element to mimic the intermittent food supply of hunters. I know you mention this briefly in the book but I'd be interested in more of your thoughts on IF as a "natural" eating pattern. Is this really how we evolved to eat?
Chris, I can tell you that I have absolutely NO opinion on this whole “we should eat as our ancestors ate” theory. My concern with this theory is that the data collection and proof of causation must be brutally difficult to do properly, but its too far outside of my area of expertise to form a true educated opinion.
There seem to be two elements to the way in which you present the benefits of fasting: a simple limiting of caloric intake but also the profound hormonal and "gene expression" mechanisms that are initiated by a fast. Which is the more important element in your view?
For the VAST MAJORITY of people, the biggest benefit will come from the caloric restriction and the weight loss, as this is the quickest and possibly most efficient way to improve many markers of health. So the metabolic, hormonal and even gene expression benefits come second in my eyes.
This does NOT mean they are not very important, just for a population that is growing increasingly obese at an alarming rate, this has to come second to simple caloric restriction and weight loss.
Is there a point of diminishing returns with a fast? You generally recommend a 24 hour fast. Is there any benefit to longer or shorter fasts?
24 hours was chosen because for me, it was the perfect compromise between scientific effectiveness and real-world effectiveness. I studied everything up to 72 hours of fasting, but I found that asking people to do anything that involved not-eating for an ENTIRE day became too intrusive to their lifestyle, thus setting them up for quick failure. I firmly believe that the effectiveness of a diet can be determined by its longevity – or how long a person can stay on the diet. And, it’s longevity is determined by its flexibility. With a 24 hour fast (e.g. fasting 6pm one day to 6pm the next), you get the benefits of fasting, while still eating every day.
Fasting seems to improve insulin sensitivity and induce ketosis. So can a low carb diet. Do carbs matter or as Martin Berkhan - another very able and helpful advocate of IF - recently wrote are carbs unfairly targeted for criticism?
There is just too much evidence with different styles of eating around the world to suggest that we should completely eliminate carbohydrates from our diet. There are hundreds if not thousands of cultures around the world, and all eat a little differently with varying amounts of carbs, proteins and fats in their diets.
And within each culture there are sick people and healthy people – a testament to the amazing adaptability of the human body and its ability to survive and even thrive off of many different styles of eating. Now, because carbs make up the largest portion of our calorie intake, and are the most readily available food calorie source, I believe we could all benefit from reducing our sugar intake A LITTLE BIT, but this is simply because I think we eat an over-abundance of this macronutrient right now. Too much of ANYTHING has its disadvantages. Carbs are no different.
Do some people need to approach this way of eating with care - I am thinking of those with previous eating disorders?
Absolutely, people with a history of eating disorders, or any diagnosed form of addiction should be very careful with ANY dietary customs or ‘rules’ that they choose to adopt.
You have let me know that you have a new book in the pipeline on protein - again looking critically at some of the popular dogma which is often unsupported by science. I'm really looking forward to reading it. Are there any other "myths" out there in terms of diet and fitness that you would like to research and critically reassess ?
Eating for fat loss (Eat Stop Eat) and eating for muscle gain (How Much Protein?) were the two biggest issues that I just HAD to tackle. Once you understand the true science behind these two areas you are able to finally relax about food. It is such an awesome experience to finally know that you don’t need to obsess about nutrition in order to build muscle or lose fat.
Now that I believe I have accomplished this, my next step is to study how the entire world eats. The different habits and customs, their origins, their meanings! I want to really explore our profound relationship with food. A step away from pure science, but just as informative in my opinion.
Will IF ever go mainstream?
Unfortunately, my belief is that IF will go mainstream and then will be ‘burned at the stake’ by the mainstream diet-media. It’s just too different and too simple. Imagine how many people would be out of work if we all realised that simply eating less would help us lose weight? Or how the food industry would suffer financially if we all ate 20% fewer calories...it simply can’t happen!
Thanks very much for the interview Brad and thanks for the work you have put into researching and writing about intermittent fasting. I've really enjoyed learning from you and IF is something that has helped my own diet and lifestyle.
I've often recommended Brad's book Eat Stop Eat as a great study of this topic. Brad's blog is also well worth reading and he has recently been posting some good short videos on Youtube looking at IF and other related topics.
If you are interested in IF I also often post bits of pieces of news and research about it here.