Introduction to Intermittent Fasting
Fasting
For those of you who’ve known us for years, it’s no secret that we follow a low-carb, high-fat Paleo style diet. We started this in 2011 and have experienced great results, with improvements in fitness, strength, body weight, body composition, and energy level. But as individuals who embrace the concept of self-experimentation, we’re always on the lookout for new concepts or changes we can make to optimize our health. A few years ago we stumbled upon something that has taken our health and performance to the next level. It doesn’t rely on new technology or expensive supplements. In fact, it’s not a new concept at all and it’s completely free: intermittent fasting.
What is intermittent fasting (IF)?
Let’s start off by defining fasting. To my surprise, there are actually quite a few different standards or definitions of fasting. The most pure example is the “dry” fast, where literally nothing is consumed. This strict methodology is utilized by some Muslims during the daily fasts of Ramadan; however, I cannot emphasize enough that I do not recommend “dry” fasting due to the real danger of dehydration. However, the most commonly used definition of fasting in dietary circles is the “water fast,” where one does not consume anything except–you guessed it–water. A slightly more liberal definition of fasting (and the one to which we ascribe) allows non-caloric beverages such as unsweetened tea, black coffee, or even flavored seltzer water. The goal here is just consume no calories. But the definition of fasting can be stretched from here. Some folks incorporate things like bone broth or MCT oil as these tend to maintain (or even accelerate) the state of nutritional ketosis, which is achieved in longer fasts (we will get into ketosis in a later series, so stay tuned). Now, any of the modifications are clearly not fasting in the classic sense, but the good news is that there is no authority looking over your shoulder and there is no absolute right or wrong way to do this.
OK, so that covers the fasting part. Now let’s consider the intermittent part. This just implies that fasting is done sporadically and irregularly. Remember those old P90X commercials where they talked about “muscle confusion?” I like to think of IF as metabolic confusion. As we’ll explore later in this series, humans didn’t evolve in an environment of plenty and constancy; we are remarkably well adapted to deprivation from time to time, and it turns out that there are some metabolic advantages to occasionally turning off the flow of calories into our bodies. The duration of caloric deprivation can be anywhere from a few hours to a few days. The most simple and most commonly practiced fasting regimen is the 24 hour fast, where one eats dinner and abstains until dinner the next night. Others prefer to eat breakfast or lunch and then not again until the next breakfast or lunch; just as long as there are approximately 24 hrs between feeding. But IF strategies can get far more complex. Some advocate alternate daily fasting as was popularized in the 5:2 diet. Others follow the “time restricted feeding” approach where they essentially fast every day for 16-18 hrs and take in all of their daily calories in a 6-8 hour “feeding window.” I’ve tried all of these, and after 2 years of experimentation, I have ended up right where I started with the weekly 24 hour water fast.
My first fasting experience
I first experimented with fasting about two years ago during Lent, where Catholics are expected to fast. During a Lenten “fast,” Catholics are supposed to abstain from meat and snacking between meals, typically only on Fridays. As you can see, this is not exactly the most rigorous standard, but gets the point of sacrifice across. I decided to take it a little further and not eat from dinner Thursday until dinner Friday–in other words, my first real fast was a 24 hour water fast. Like anything else in life, it was quite challenging at first, but was made somewhat easier because I was doing it for a higher purpose. It may also have been easier for me, as my years of paleo-style eating have made me more “fat adapted” (capable of easily switching from carbohydrate to fat metabolism for energy) than the average person. I still found it to be a challenge though, both mentally and physically, but it wasn’t painful and I could go about my daily activities without any real difficulty. On the first few fasting days I did experience some mental fogginess and irritability (feeling “hangry” I guess), but as the weeks went by I found that fasting became easier and I began to see the benefits. By the time Lent was over, I realized how much I liked my fasting experiment and continued to do it once a week since then. Rachel came on board with the practice after a few months, and before long it was a regular “habit” in our home (not for the kids though!). After about a year of fasting once weekly we decided to take things another step further and experimented with some longer multi-day fasts. We will get into this in lots more detail in future posts, but suffice it to say that after 2 years of incorporating IF into our lives, it has definitely become of our most important health habits.
Stay tuned to the blog over the next few weeks as we share more about IF, including a look at the metabolic advantages, rationale, safety, and personal results.