My thoughts on intermittent fasting

I’ve written quite a few technical posts recently, so I figured I’d post a quick one about health and fitness. Over the past year, I’ve followed eating schedule known as intermittent fasting (IF), which, as the name suggests, consists of a small eating window followed by a longer period of fasting. Many consider intermittent fasting to be a fad – I’ll admit, I was rather skeptical when I first heard of it – but I eventually decided to give it a shot after reading about some of the purported physical and mental health benefits.

From 2013-ish to early 2015, I was incredibly bad about sticking to IF. However, since March 2015, I’ve stuck to IF rather religiously, to the point where it’s become a way of life for me. My current schedule is very Leangains-esque, and consists of an eating window from 12PM – 6PM, followed by a water & tea fast until the next day. I don’t consume any solid food during the fast, regardless of its caloric content. For those of you who don’t know about Leangains, I highly recommend visiting the site. The author, Martin Berkhan, has posted a plethora of great IF-related information.

I’ll use the rest of this post to discuss some of the changes I’ve noticed take place with my body and mind. This post will be short, but if you don’t feel like reading it all, the last section should serve as a nice tl;dr.

Mental focus and energy levels
This is often the first difficulty most newbies of IF experience. However, apart from the first couple of adaptation weeks, the belief that “brain fog” occurs in the absence of calories is entirely misguided. I personally noticed that I now have intense mental acuity and physical energy right after waking up, lasting all the way up until the end of my fasting period, something that was not the case prior to IF.

Think about it from an evolutionary perspective. The earliest humanoids, i.e. hunters and gatherers, were forced to explore constantly in order to find food. If their bodies hadn’t received a proper meal in a while, their minds would kick into overdrive in the hope that doing so will result in food in the near future. Admittedly, this comparison is not perfect, but the analogy is nonetheless valid – your body will not enter a state of hibernation a couple of hours after your last meal. Furthermore, the infamous “starvation mode” doesn’t occur until about 48 to 72 hours into a fast. If you’re willingly fasting for that long on a regular basis, you’ve clearly fucked something up and should probably go see a doctor.

Strength gains
Needless to say, IF isn’t particularly conducive to strength or muscle gains; strength is built on a caloric surplus, and IF inherently limits the amount of food that you can eat; it’s considerably more difficult to fit 2500 calories in an shortened window of six hours than a “regular” window of sixteen. However, that doesn’t mean that strength gains are impossible to acquire while on IF. Since January of this year, I’ve been able to increase my 1-rep max on squats from 93kg (205lb) to 107kg (235lb), and my deadlift from a measly 61kg (135lb) to 134kg (295lb)1. During this entire time, I’ve also been able to maintain a reasonable level of cardiovascular endurance via circuit training once a week.

For a 72kg (160lb) male, these numbers are still absolute garbage, but I think they show the potential for strength gains on IF. The key is to eat consistently throughout the entire window, and to make sure that enough protein and carbs are consumed to properly fuel and recover from strenuous workouts. While I may have been able to see faster and better results if I hadn’t stuck to IF, the strict eating schedule has allowed me to stay quite lean (~10% body fat) throughout the entire process. In my opinion, this is nothing more than a nice bonus. More on that in the next section.

Long story short, strength and muscle gains are very possible while on IF, so long as you maintain a caloric surplus in addition to a balanced diet.

Fat loss
Fat loss is perhaps the main reason most people hop on IF to begin with. After all, who doesn’t like a nice set of washboard abs and definition along the arms and legs? Indeed, a good number of IF practitioners experience favorable fat loss rates, but that’s not my primary (or even secondary) reason for practicing IF. Sure, it’s nice to admire yourself in the mirror and brag about your looks to other inferior human beings. Simply stated: abs are overrated. Period. At some point, you realize that pretty much the only other people who care about your shirtless look are other dudes at the beach… who are also shirtless. Don’t let your perception of good looks sway you to be on IF – do it for the mental and physiological health benefits and it won’t feel like a “diet” at all.

Choosing an eating window
While I’ve stayed true to IF over the past year, the eating window is something that I’ve constantly been experimenting with. I started out with daily 12PM – 8PM window, eating one meal at noon and another around 7, all while sprinkling fruit and nuts throughout the afternoon. This eventually evolved into a 1PM – 7PM window before settling on a 12PM – 6PM window. I also recall trying a 4PM – 6PM eating window, but scrapped it shortly after discovering how difficult it was to fit a full day’s worth of calories within a period of two hours.

Brief side note: actively limiting calories while on IF (for fat loss) is something that I do not believe is necessary even if fat loss is your primary objective. Be strict and consistent about your eating window, but eat big meals. You’ll likely notice that you really haven’t eaten as much as you thought you did at the end of the day.

Social engagements while on IF
In my experience, this is perhaps the only downside to IF. When meeting up with friends for the weekend or going out to a bar Friday after work, you often question whether or not it’s worth it to break your fasting routine for the sake of appearing normal. I’m very much a creature of habit, and breaking a particular cycle can easily lead me to fall out of line, so to speak. I personally still try to stick to my eating schedule during such outings, but it’s probably best to use your own better judgement here.

All in all…
Intermittent fasting isn’t a magic get-on-it-and-fix-all-your-problems method of eating, but it’s allowed me to remain relatively lean whilst still enjoying a variety of food. It’s also enabled me to be markedly more efficient work-wise in the morning, with the added benefit that I rarely ever think about food anymore. While there may also be some long-term benefits to time-restricted feeding2, I do it because it’s become a way of life for which there are few downsides.

At the end of the day, the best method of eating is one that works for you. IF has certainly worked for me.

1I’ve been doing squats regularly for a while, but started deadlifting seriously around the beginning of 2016. The squat work prior to this certainly helped my deadlift shoot up in such a short period of time.
2There’s been some studies on mice which suggests that certain forms of IF may slow aging and prevent mental deficiencies, but the evidence is somewhat murky and it remains unclear as to whether or not these benefits translate to humans.