One of my goals for 2020 was to stick to an intermittent fasting routine. I completed 6600 hours of fasting in 2020. On average, that’s 18 hours of fasting every day, for 365 days. Other interesting stats include the longest streak of 440 fasts and the longest fast of 37 hours. I did reasonably well to maintain a healthy weight despite stress-induced binge eating during the pandemic.

My fasting journey started in mid of 2019. In the second half of July 2019, I was experiencing sharp pain in my left arm and shoulder. During that week in the middle of the night, I woke up all sweaty, with shortness of breath. I anxiously started googling for the nearest urgent care location, and the shortest path to reach there, just in case I need to rush. Fortunately in the next few minutes, I regained control of my breath. I drank a glass of water and decided to wait until morning. I visited my primary care physician the next day to find out what’s going on, and potentially plan for my angioplasty or bypass surgery (or whatever they do to fix the heart-related problem).

I like my doctor. He is not aggressive with any medications or prescriptions. His advice usually contains words like an embrace, adapt, or wait. After performing preliminary checks he confirmed that while the incident was indeed frightening, and showed all the symptoms of cardiac arrest, it was not a heart attack! The subsequent lipid profile tests etc confirmed his diagnosis.

While the diagnosis was good, when I carefully looked at the lab results, my LDL cholesterol was at the upper threshold of the safe range. My BMI was indicating that I was overweight. The pain in my left arm wasn’t completely gone. What if my doctor was wrong? This was a clue that I needed to make changes in my lifestyle. Fortunately, two things happened.

1. I read an interesting article about magician Penn Gillette losing 100 pounds by fasting for 3 months. He essentially followed One Meal A Day approach to maintain the weight loss.
2. I met a friend who had lost about 20 pounds in 3 months by following the intermittent fasting practice. It was super impressive.

I started taking deep dive into some internet research to understand the basics of intermittent fasting. While it looks like a modern fad, it has been practiced for centuries by various cultures and religions. For example, Hindu Lunar calendar has a 2-week schedule based on the full moon and new moon. On the 11th day after the full moon and new moon, one fasts from sunrise to sunset. That’s twice a month. It’s called Ekadashi fast.

The physiology of fasting is fascinating. Once you have the food, the digestion kicks in, and food breaks into glucose, amino acids, and fatty acids. Ghrelin or the ‘hunger hormone’ decreases and insulin increases. Insulin carries the nutrients into cells to be stored as glycogen, fat, etc., or used as energy. This phase - anabolic - lasts for 4 hours.

After the anabolic phase, the catabolic phase kicks in. For the next 12 hours, your blood glucose continues to drop and the liver starts breaking down glycogen for energy.

The catabolic phase transitions to the fat-burning phase. That’s 16 hours after you ate. As the name indicates, during the fat burning phase fat stores break down for energy. The fat burning phase lasts for 8 hours and transitions into the ketosis (and the deep ketosis phase).

I will not go into a lot of technical details here. That’s the basic overview of the physiology of fasting.

Coming back to the point. In August 2019, I started my fasting journey with a 16/8 schedule which meant 16-hour fasting and an 8-hour eating window. Just within a week or so I got used to it. I found it too easy, then I transitioned to the 18/6 schedule. And eventually settled on the 20/4 schedule for most of 2019. I use Zero Fasting to keep me motivated. I got the results I hoped for and did not experience any pain in my left arm or shoulder since then.

Note: To put in Penn Gillette’s words. If you take health and nutrition advice from a random internet stranger. You are an idiot.