Intermittent Fasting (I.F). I keep seeing it pop up in blog posts, the news, fitness magazines and through friends who have tried to attempt it. Fasting is obviously not a new phenomenon. However, when people mention a desire to try it out, I usually feel more worried than excited because of all the misguided information out there. Particularly when it comes to I.F and women, for which little research has covered. The majority of resources that promote I.F don't even address that there is difference in how men and women experience the fasted state.
Small note - If you're a man and reading this, it may not be entirely be relevant to you. However, a women you know may be interested so please keep reading! Plus, if you're totally new to I.F, there are a bunch of useful links at the bottom of the article that may be of interest.
WHAT IS INTERMITTENT FASTING?
Intermittent fasting is just another way to describe abstaining from food for 12-24 hours (although some people do longer fasts). Often, fasting doesn't affect overall caloric intake, but rather confines eating to a specific window of time in the day or week.
There are quite a few types of I.F :
- Alternative Day Fasting (36h/12h) : This means you fast every other day. This usually works out to be 36 hours of fasting and 12 hours of eating because you eat from say 9am - 9pm Sunday, not at all Monday, then begin eating again 9am Tuesday.
- Eat Stop Eat (up to 24h fast 1 or 2 days a week) : Fast of up to 24 hours. Fast only once or twice a week.
- The Warrior Diet (20h/4h) : This diet encourages you to eat the majority of your calories within a 4 hour window at night. The remaining 20 hours (obviously some of which you'll be asleep) you consume light snacks such as berries or yoghurt.
- Leangains (16h/8h) : This plan advocates eating all your daily food within an 8 hour window of the day, for example, between 1pm and 9pm. There are also some other guidelines such as fasted workouts, BCAA supplements and post work-out meal specifications.
- The 5:2 Fast Diet (2 days a week of calorie restriction and 5 days of normal eating) : Women are encouraged to eat 500 calories and men 600 on the calorie restricted days. The other 5 days are normal calorie intake.
- Random meal skipping : This isn't really a protocol but advocates skipping meals randomly. I think we all do this anyway without realising. For example, if you're travelling or have a really late night out with friends and only wake up in time for lunch the next day.
WHAT ARE THE HEALTH BENEFITS OF INTERMITTENT FASTING?
There are many reported benefits of IF fasting :
- Increased lifespan
- Reduced blood lipids (triglycerides and LDL cholesterol)
- Lowered blood pressure
- Cancer resilience (as well as being able to cope better with chemotherapy)
- Autophagy (controlled digestion of damaged organelles)
- Ability to burn fat
- Neurogenesis (birth of new neurons)
- Blood sugar control
- Improved cardiovascular function.
You can read more about the benefits in this article on Mark's Daily Apple.
MY EXPERIENCE WITH FASTING
There is a lot written about I.F in terms of implementation. For those who train hard, there are many resources on how to incorporate it into your lifestyle with details on carb cycling, types of exercise, when to exercise, supplementation and when not to fast at all (see MDA and Leangains). I don't want to just regurgitate what's already been said by people who have done a lot more research. The point of this post is to add new insights extrapolated from my own 3 year experience of practicing I.F. I hope anyone on a journey of their own can take something away from this.
My first experience with fasting was when I was 20 years old. I practiced Alternate Day Fasting, although I hadn't read anything on I.F so wasn't aware of it as a common practice. It was not strictly fasting as alternate days were set to a limit of 500 calories in the form of liquids (soup/juice/diet soda). Over this time I was exercising 6 day a week. It was all very cardio centric; ballet, basketball, running, swimming, cycling and bikram yoga. I was the leanest I have ever been and probably ever will be but I had serious problems. Firstly, insomnia. I would get home from a busy day at college after having cycled 20km and gone to a bikram class, yet still be unable to sleep. I would lie awake for hours, my body feeling exhausted yet unable to find rest. Secondly, I didn't get my period for three months. Major red flag! It was years later, reading over Stefani Ruper's posts on this when everything made sense.
There have been some human and animal studies done on the effects of I.F to improve weight loss and cardiovascular function. The study most relevant to this argument is one done on rats to show sex specific responses to calorie restriction and I.F. Firstly, the changes seen in the female rats was directly proportional to the severity of caloric restriction. This was not the case with the males. The females suffered a decrease in size of their gonads, whereas the males exhibited no change in this department. Females became hyper alert, energetic, developed irregular cycles or suffered a complete loss of estrous cyclicity. As Stefani Ruper points out, these studies show a a myriad of other positive outcomes, so details on sex specific differences can be treacherously lost.
As most of us know, females have a higher body fat percentage than males. This is because fat is required to cope with nourishing a child or even for a potential pregnancy. Staying hyper alert and energised is a 'find food' response to what the body thinks is starvation. This 'starvation' mode also explains the disruption in the rats cycle. When the body thinks there is not enough food, it prevents the ability to get pregnant.
Women on I.F diet regimes women often report feeling more alert, energetic and able to learn. This should not be confused as a positive outcome in all cases. Even though it may seem positive, this reaction could be indicative of a more serious underlying imbalance.
You might say that my horrible diet of fruit juice and diet soda resulted in an inability to cope with Alternate Day Fasting. This could be true. Now a complete paleo/primal convert, my response to it could be entirely different. However, the evidence in the studies sited by Stefani Ruper are pretty compelling. I am not inclined to try this type of fasting again.
My second experience with I.F was in some ways imposed. I was working at a jungle hostel in Costa Rica at which the only breakfast available was pancakes made from dry instant pancake mixture. I decided I would skip breakfast and just drink tea instead. Lunch and dinner were always pretty hearty (but not strictly primal) including fresh veg, local meats, rice and beans. I more than made up the calories I missed at breakfast by eating a very large lunch and dinner. After about a month I noted becoming leaner, despite doing no exercise aside from gentle yoga and the occasional long walk.
Later on in NYC, I tried to recreate the fasting experience I had in Costa Rica. Living in NYC meant I was more exposed to the literature on I.F as a health practice. Before that point all my experiences had been somewhat undirected and not at all mindful. I soon found that without the restriction of being trapped in a jungle, it was hard not to have breakfast. I would get hungry and there were far many temptations around. I was inspired by Dave Asprey's Bulletproof Intermittent Fasting protocol as it would allow me a cup of butter coffee in replacement of breakfast. The idea behind this was (as stated on his website): "The fat makes your body stay in ketosis so your physiology gets the benefits of Intermittent Fasting, but the fats provide enough fuel for your brain that you don't get the same stress response. You still have energy (it feels like more energy than a normal breakfast provides), and you can still make hormones."
Quite soon I ran into problems again. I've always had a sensitive bladder prone to bladder infections. Adding a coffee to an empty stomach and letting it sit for 4 hours or so did not do well for my bladder. I suffered from a dull pain that would sometimes last for hours among other unpleasantness I would rather not mention. I'm not going to bother creating a link to read about this as all you have to do is google 'caffeine' and 'bladder problems' and you will see this is a widely reported problem.
WHY I DO STILL PRACTICE INTERMITTENT FASTING TODAY?
This image portrays how I felt about I.F up until this point.
For my final and successful attempt at I.F, I went back to the research cited earlier. I realised that all studies on both humans and rats were either calorie restrictive (at 20% or 40% calorie restriction), Alternate Day Fasting or HFG (a high fat/low carb diet). None of the studies looked at fasting regimes that are homogenous every day and don't affect calorie intake but rather the window of time in which you eat (1pm - 9pm, for example).
This may seem like a small revelation but combined with a few other tactics, here is why I think it finally worked:
The hormone ghrelin. Scientists have found a group of cells in our stomach lining that release a hormone called ghrelin in expectance of a meal. It's like an internal meal clock that reminds us we should be expecting food sometime soon. I find that if I break my fast at 1pm every day, after a while, I'm not hungry before that point. It's amazing how 'hunger' can be very psychological. I've created a routine where my body expects food at 1pm therefore I'm usually hungry at that time. I don't have my body nagging at me in confusion for food at different times as it did during Alternate Day Fasting.
It's important to be fat adapted before you start fasting. Mark Sisson's list of pre requisites for I.F are as follows: "be fat-adapted, get good and sufficient sleep, minimise or mitigate stress, and exercise well (not too much an not too little)". In very simplistic terms, being fat adapted means you can metabolise both fat and carbs for energy. This has a whole host of benefits that are covered in this article, however, a lot of people have not developed this ability due to the amount of carbs they consume or the frequency of meals. It seems likely that my body was still adapted as a sugar burner and not a fat burner, which is why I found fasting so hard previously. Even though I was primal (per the food type I was eating). I also ate far too many paleo pancakes and those amazing coconut covered date balls you find in pretty much every health food store in the US. It's important to be honest with yourself in terms of how much sugar (even the good kind) you consume.
Social factors are also a massive issue I haven't spoken about much, however, I don't want to undermine their pertinence. Fasting is quite difficult when it comes to family meals or eating out with friends. Social isolation due your crazy diet regime somewhat downplays the overall benefits of the diet itself, in my opinion. By just skipping breakfast (often a solo or on the go meal anyway) you're not disrupting too much of what it is to be a person with 'normal' eating habits.
- A longer fasting window : I generally stretch the window from 8 hours to 9. This feels more like a comfortable fast. IF is definitely a good exercise in helping determine what actual hunger is rather than just 'mind' hunger or habit, however, it should never feel like you're struggling.
- Sustainability : Remember that feeling you get as a kid on a sunday night...a kind of sinking dread for the week to come? IF should not feel like this! In fact no aspect on your health/wellness regime should feel like this. Being gentle with yourself may make you feel like progress is slow, however, the chances are you'll soon be ahead of those who are bullying themselves into 'health'.
- Online I.F resources : Beware of the sites out there that advertise I.F as an ideal tool for weight management. If you get through a guide on I.F and it doesn't mention a difference in the way women and men experience fasting, it's probably safe to disregard it entirely (if you're a women). A lot of the popular fasting sites advertise I.F as a way to eat as many cookies as you want and still lose weight. There are so many things wrong with this I could write a whole post on it! The main thing is; your regime shouldn't be a punishment that you feel the need to escape from by eating cake.
- Listen to your body : this may seem like an obvious one but it's still important. For example, if I'm really hungry at midday I bring the whole window forward at hour (rather than drinking butter coffee). People argue back and forth about the science behind fasting and what research shows, however, it can be a completely tangental factor causing the problem. For example, my bladder aliment. It had nothing to do with the actual fasting itself but was an unfortunate collateral. If there is something wrong, think about your life from all angles to pinpoint what the root cause could be.
- Breaking the rules : I realised that breaking the 'rules' for one day doesn't automatically mean failure. This enabled me to sustain this practice and it's benefits for much longer.
I hope this will be of help to anyone beginning or already on an I.F journey. Please feel free to contact me with any questions!