My Experience With Intermittent Fasting

WARNING: I am not a doctor or health practitioner. Just because I look good in Speedos does not mean you should take my advice or do what I do. What works for me may not work for you and vice versa. Beware of people like me who take an N=1 experiment on themselves and get all preachy as if they have the answer… I'm looking at you, Tim Ferris. 

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Being a huge fan of the Paleo diet and the amazing results I have seen (body composition, energy levels, overall health) in the four years I have been eating in this manner I thought I'd toy with this idea of Intermittent Fasting (IF). In this article I first explain a bit about IF and then go on to describe what happened to me when I tried it for six weeks last year. It ends with some thoughts on who may benefit from IF and who should probably stay clear. 

What, IF?

Basically, Intermittent Fasting is an eating pattern that alternates between periods of fasting and feeding. Ramadan is an example of IF (although you probably won't get smitten by Allah if you don't observe this type of IF strictly). IF may involve alternate-day fasting, fasting one or two full days a week, fasting every day for an arbitrary number of hours or any other combination. 

The form I chose to do it involved a 'condensed eating window' of four to eight hours a day, every day. Some would call this a 16:8 or 20:4 intermittent fast. The timing and ratio changed daily but effectively I was not eating anything from around 9pm at night until some time between 1pm to 5pm the next day depending on when I trained. 

I was training in the fasted state. And by training I mean heavy weight training often paired with metabolic conditioning (high intensity interval training ala CrossFit). In hindsight I think this was a mistake, but more on that later.

From when I broke fast after my workout I would eat as much and as often as I liked during that four to eight hour period until starting the next fast. Thereafter it was just water and black coffee in the mornings until my next feeding window. Not that crazy, really. (Is it?? I can be a bit crazy sometimes... Who said that?) It's important to note that I was also eating low-carb at the time. Probably between 50-100 gm of carbs a day, which is very low for my activity levels and size. 

Why the F would you do that?

Good question! Well, firstly I am an inquisitive person and I wanted to see what all the fuss was about. IF has become very popular in the whole Paleo-sphere and there have been quite a few (animal) studies over the years suggesting that calorie restriction and/or intermittent fasting could really have some potential health and longevity benefits. 

For example, in multiple animal studies rats that were fasted (usually alternative days of no food) ended up living up to 50% longer than the 'eat whenever you want' control group. It seems like the mechanism was somehow related to fertility - in scarce times when the body doesn't have enough energy to reproduce it will delay the aging process in order to live long enough to reproduce. The fasting rats' telomeres - the ends of chromosomes that shorten as you age - degraded at a slower rate.

I later found out that the latest research was suggesting that this longevity effect is somewhat overstated and nowhere near as prominent in primates/humans. In particular, one primate study suggested that severe fasting (one week on/one week off) for your whole life may increase life span by up to seven years for a human. Hardly worth it for a life of misery in my opinion! The theory is that unlike rodents, large mammals with long gestation periods (like humans, elephants etc) require relatively less energy to rear their young than, say, mice, for whom rearing young requires a greater proportion of their total available energy. Thus the longevity effect of fasting is far less for humans than rats. 

The other, perhaps more enticing suggested benefit of IF for a body-conscious sucker such as myself is an overall improvement in body composition (maintain lean muscle, lose fat) that IF proponents push. Basically, by fasting large portions of the day your body will be in a ketogenic (fat burning) state for most of the day, which should enable stored body fat to be burned for fuel rather than all the readily available glucose from that big bowl of sugar-nothingness known as cereal and large glass of refined fructose (Orange Juice) us fat Westerners have been told constitutes a “healthy breakfast”. In a sense, IF should turn you into a 'fat burning beast' as Mark Sisson calls it. 

My experience with Intermittent Fasting

So you're wondering how not eating most of the time worked out for me?

The Good

I did IF consistently for about three months last year while living in London. After the first few days I actually found it easy to not eat in the mornings. I was drinking a lot of black brewed coffee and actually felt really mentally alert during the fasted period. Kind of like when I was a kid playing football or doing Athletics and you have that semi-nervous, super-alert feeling when you are about to run out on the field. This is probably a good indication that my sympathetic nervous system (fight or flight response) was dominating during the latter part of the fasted state and not giving my parasympathetic nervous system (rest and recover) enough field time.

Anyway the first few weeks I was performing well in the gym, and was really growing to like the feeling of not eating for hours on end. It is strangely addictive and definitely gives you a buzz. It makes sense to me that our Paleo ancestors often went very long periods with no food and would often have to hunt in the fasted state and so I guess there may have been some evolutionary pressure on the ability to ramp up alertness when we are very hungry. 

Also, It is quite liberating knowing that you don't have to think about preparing food or snacking every few hours. I think it can help with productivity too. Sometimes around midday I would get quite strong hunger pangs that lasted for about an hour but they would always pass and I would feel great again. As soon as I started training I would feel very energetic - "on the hunt" I guess you would say. 

I have no doubt that we as a people these days do not embrace hunger enough. Instant gratification, greed and relative prosperity have made being hungry a frowned upon and unnecessary condition. It's a shame. Furthermore, I find the natural/Primal hunger you feel during a fast or when in the ketotic state is subtle and tolerable. Contrast this to the modern hangry (hungry + angry) food craving cycle most Westerners face every couple of hours when their blood-sugar plummets shortly after consuming a sugary/grainy meal or snack. I think the 'six small meals a day' myth is defunct for the average person.

The Bad

While my performance was good in the gym for the first few weeks it kind of plateaued after that. I also seemed to lean out a couple of kilos in that initial period but by around week three or four I was back to my normal size/weight again. It started to become obvious that IF wasn't going to turn me into a freak that could walk around at 5% body fat with veins popping out of my abs and bench-pressing 200kg. Don't worry, I'm fully aware that these are unrealistic goals and I not particularly desirable! But I was hoping that this would be a kind of cheat to being super-ripped all the time while also being able to gorge, drink booze and eat a bit less clean than usual. Spoiler alert: It isn't… for me at least.

When you fast for 16-18 hours everyday and it finally comes time to eat, you overdo it. At least I certainly did. I'm always a big eater. I'd say I average 3000-4000 calories a day. I'm very active and I eat high quality whole foods and relatively low levels of carbohydrate so I can get away with an energy-dense diet. When you are trying to get in all your daily calories in just a few hours you really have to eat a lot. 

I am a bit of a fat-kid at heart so I kinda like gorging myself. I think many people would struggle to get enough calories in for the day in just 4-8 hours which is probably why IF is so often heralded as a great weight-loss tool. By default people fall into a substantial calorie deficit and the weight just comes off. But for me it just meant I was eating massive meals and grazing for the rest of the eating window. 

I would routinely eat a whole 100gm block of 85% cocoa dark chocolate in the evening, after already consuming a can of coconut cream, sometime a whole chicken (they are small in the UK) and copious amounts of vegetables, salads and fruit. Ironically, I think I was eating more than I used to eat when not doing IF. More troubling though, I was eating more of the energy-dense foods that I try to limit such as the dark chocolate, coconut cream and nuts. It makes sense that I was probably going to these foods to get the calories quickly and easily as my time frame for eating was restricted. (There are only so many salads and vegetables one has time to prep and eat in 5 hours). I didn't gain weight but I started to feel sluggish.

The Ugly

Around week 10 or 12 I started to feel pretty flat. I wasn't sleeping well, my performance was declining in the gym and I started to feel more anxious. It became clear that the honeymoon period had ended and my body wasn't so happy with this new normal. When I couldn't get to sleep at night I knew something was wrong. My body was under stress and not recovering as it should. 

My sympathetic nervous system (fight or flight response) was in overdrive. I knew it was probably a cortisol issue, adrenal fatigue, a slow-down in thyroid function or most likely a combination of the three. All of these physiological responses are very typical of type-A personalities (me) who push themselves too far, overtrain, under sleep, go too low-carb and are generally addicted to adventure, stress and stimulation… and caffeine!

I was becoming mildly addicted to the buzz of the fasted state, but then obsessing over food more than usual. I had the gut feeling that this wasn't a sustainable or healthy endeavor for me. 

IF's and buts

I stopped IF and went back to a more normal routine, eating breakfast most days. I think my issue was probably with the fact that I was eating too low-carb, training too intensely and trying to do IF all at the same time. When you do intense CrossFit type workouts that are very glycogen (muscle glucose) dependent you really need enough carbs in your diet to replenish the glycogen stores or you will literally run out of gas and start to feel like crap and get all those symptoms I mentioned above (poor sleep, fatigue, anxiety, brain fog, etc). It seems obvious but sometimes you just have to learn for yourself, the hard way!

I've learned my lesson now and when I train intensely I make sure I get enough starchy carbs from things like sweet potato and occasionally white rice. This seems to be working really well for me right now and I'm looking, performing and feeling great - as Robb Wolf would say. (Love that little guy).

I still do the odd IF day now and again but would never do it for prolonged periods of time. It can be a good tool for some people, with the following caveats…

Who should definitely not use IF:

IF is probably not a good idea if you are: highly active or a professional athlete, a person prone to eating disorders, pregnant, highly stressed, partying a lot or working irregular night shifts, suffering adrenal fatigue, diabetic or otherwise metabolically deranged. 

People who could get away with IF a few days a week:

I AM NOT RECOMMENDING INTERMITTENT FASTING. However, if you are healthy, moderately active but not an athlete, sleep well, eat well but are a bit overweight and need a new simple strategy to lose some fat then this could be an option. If you are lean and want to try IF, ask yourself why? Make sure your motives are genuine. 

Take aways from my dabble with IF:

• Hunger is good, natural and largely absent in our society
• Don't do IF with low-carb and high intensity training. This is a recipe for disaster! 
• Used wisely IF can work well for some people
• I believe IF would work best as a random, sporadic practice rather than doing it every day for extended periods of time. Randomness breeds adaptability, resilience and robustness. 
• If you choose to do IF I would highly recommend taking one or two days off a week.
• Take everything I say with a big pinch of iodine-enriched salt as this is purely an N=1 experiment. We are all unique snowflakes who require unique lifestyle guidelines. 

12-month update:

About six months ago I began to do what Dave Asprey calls “Bulletproof Coffee Intermittent Fasting” (BPCIF) This involves the same 16:8 intermittent fast that I was doing except with the addition of consuming one ‘bulletproof coffee’ in the morning. Dave proposes that you get most of the benefits of IF (cell autophagy, insulin sensitivity, improved body composition etc) due to the fact that you are still fasting from carbohydrate and protein. However, the fat from the butter and MCT oil gives you the fuel necessary to get you through the morning and optimize brain function and performance. I personally find that BPCIF works very well for me. I do this most days of the week. I don’t think it is good to keep exactly the same routine when it comes to meal frequency and size. I try to mix it up to keep my body guessing. 

If you found this article interesting or helpful you can do me a HUGE favor by sharing it with your friends using this link for Facebook.

Thanks for reading. You might want to check out my post on Bulletproof Coffee next. 

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Some links from sources I trust on IF and potential benefits and problems:

http://chriskresser.com/to-intermittent-fast-or-not-to-fast-that-is-the-question

http://www.bulletproofexec.com/a-bad-combination-for-women-intermittent-fasting-and-paleo/

http://robbwolf.com/2012/06/14/restricted-feeding-window-4-months/

http://chriskresser.com/intermittent-fasting-cortisol-and-blood-sugar

The mice study:  Hatori, Megumi (2012). 'Time Restricted Feeding Without Caloric Intake Prevents Metabolic Diseases in Mice Fed a High Fat Diet'. Journal of Cell Metabolism, June 9, 2012.

Image Source: http://agrenlay.deviantart.com/art/Il-buono-il-brutto-il-cattivo-168619986