The Intermittent Fast
The Intermittent Fast
Most people have heard of intermittent fasting connected to some of the latest weight loss fads today. The ketogenic lifestyle is the only one that might be more popular. While it is effective for weight loss if implemented correctly—especially if combined with a ketogenic lifestyle—it can be volatile if approached poorly. If effectively maintained, however, it is incredibly freeing, and even though the overall principle sounds rather outlandish to some there is much to be learned about our bodies from this process.
I feel obligated to mention that I am not a medical professional. I am not a health expert. That said, I maintained a ketogenic intermittent fasted lifestyle from March 25th, 2020 until January 7th 2021. While I am no longer continuing my ketogenic lifestyle, I am maintaining a version of the intermittent fast.
The basic principle of intermittent fasting is taking sustained time each 24 hours where you do not eat in order for your body to process all of the nutrients you’ve consumed that day, burn fat through ketosis (the process by which your body generates energy by breaking down your body fat rather than carbohydrates in your bloodstream), and to allow your gut bacteria to replenish more effectively. The most common intermittent fasting windows follow a 16:8 split or a 14:10 split. this means that you have either an 8 or 10 hour window to eat for the day and then, once your feeding widow is over, you wouldn’t eat again for another 16 or 14 hours. If placed on a regular day, this can look very normal—10am breakfast, 1pm lunch, 5pm dinner. nothing about that seems strange really, but there is a great deal of discipline required to maintain your fast through evening or morning hours especially when snacks can be so appealing. There are only 3 things that can be consumed outside of the feeding window—water, plain tea, and black coffee.
During my deep period of fasting last year, I chose my feeding window to be 11am-7pm to allow for a later dinner time. As I’ve gown in my fitness journey, I’ve found that I prefer to have a meal after my workouts if they cannot be four or more hours before. Late dinners allowed me to go on an eight mile run after work without having to worry about dinner beforehand. Over all I began to appreciate the mental clarity that accompanied periods of fasting, I enjoyed not having to worry about eating when I was outside of my window, and it accelerated my ascent into greater fitness—between March 1st and April 28th I went from being in shape to run 5k to being in shape to run a half-marathon. I want to clarify that fasting was a supplement to the hard training I do on the road. It was not the main cause of me dropping more weight or getting in that level of shape.
For all of its benefits, however, my mornings definitely got difficult. There were some days when I felt hungry enough that I opted for a 14 or 15 hour fasting window, and those did not throw off my progress. The days I powered through, however, prevented me being able to perform at my highest levels on my instrument. My brain just wasn’t as “on“ as it could be. That said, I have been especially good about my sleep since the August of 2020 and sleeping 8 to 9 hours a night definitely makes intermittent fasting much easier. Add that amount of sleep to a morning workout, and it’s almost all taken care of.
Ironically the wacky part can be your feeding window. There were many days I felt like I just couldn’t stop eating. On a ketogenic diet that’s not as much of an issue, but because intermittent fasting isn’t keto specific that can cause lots of problems with folks who keep a more standard American diet. A good way to think about it is this… your body needs those nutrients, so whatever you don’t eat now you are going to eat later.
At this point I’m taking a bit of a different approach. In order to support my pursuit of running marathons, I’ve sought a different macronutrient split, but I’m maintaining an intermittent fast at a lower ratio (12:12 or 13:11 depending on the day) in order to gain the primary benefits of letting my body recover from processing nutrients from the food I’ve consumed—this is the big takeaway from this process really. Your body spends a lot of effort processing the nutrients you put into it, and it needs time to recover and replenish itself. This points to why diets of less processed foods work so well. Your body doesn’t need to do as much to process the nutrients. I would be interested to see how much more energy folks would have if they approached their nutrition this way.