I’ve been reading and hearing about the supposed benefits of intermittent fasting for some time now. Several bloggers I follow have recommended intermittent fasting, including Mark Sisson, Richard Nikoley, and Dr. Mike Eades. Richard (of the Free the Animal blog) in particular seems to have good success with IF.
I never tried it, however, for the simple reason that going 24 hours or more without eating sounded rather awful. Whenever I tried very-low calorie diets, I was usually halfway to miserable by bedtime on the first day … cranky, mentally foggy, and waaaay hungry. I remember trying to get by on Slim-Fast for breakfast and lunch, only to find my hands shaking by mid-afternoon. I would be counting the minutes until dinner, when I could eat a real meal.
Of course, I tried those low-calorie diets back when I was living primarily on carbohydrates and had conditioned myself to be a sugar-burner. Now that I’m on a low-carb diet and have conditioned my body to depend primarily on fat for fuel, I often skip breakfast anyway just because I’m not hungry yet. So when I recently listened to a podcast about intermittent fasting, it occurred to me that I could probably try a 24-hour fast now without feeling miserable.
It so happened that I slept late on Wednesday, and by the time I finished dealing with emails, DVD orders, blog comments, and a couple of phone calls with clients, it was already 2:00 p.m. My last meal had been some sliced turkey at midnight, so if I could just go without eating for another 10 hours, I’d have a 24-hour fast under my belt.
I haven’t read up on intermittent fasting nearly as much as Mike Eades or Richard Nikoley, but from what I understand, the benefits are largely hormonal. Insulin levels come down, while both glucagon and human growth hormone go up. Some body-builders claim intermittent fasting not only makes them leaner, but stronger, thanks to the human growth hormone.
So, what the heck, I decided to push on through until midnight without eating. (I did, however, start the day with my usual big cup of coffee. You don’t want to be anywhere near me if I don’t get my morning coffee.)
The biggest surprise was how easy it was. I felt a few “Feed me, Seymour!” grumbles around dinnertime, but they passed. No mental fog, no shakes, no sudden urges to beat my children. I can only assume my body was doing a good job of mobilizing fatty acids and ketones for fuel.
I considered going to bed without eating, but decided 24 hours was good enough for my first fast. I ate some turkey and a handful of almonds at midnight. (My wife, a dedicated bargain shopper, bought turkeys on sale before Christmas and froze them. I believe we’ll be having a roasted turkey once per month until the Fourth of July.)
My first fast was so painless, I decided to try a 36-hour fast next. On Saturday night, I indulged in some red wine, cheese, and two big handfuls of mixed nuts while watching “Band of Brothers” on DVD. As is often the case when I eat a late-night meal, I wasn’t hungry at all on Sunday morning. I didn’t have plans for the day other than reading and watching the football playoffs, so it seemed like a good choice for an all-day fast.
Once again, I was surprised at how painless it was. Curious as to why I didn’t have the shakes or feel light-headed, I checked my blood glucose around 6:00 PM and was surprised see it was around 95. It’s usually in the 85-90 range when I wake up in the morning. Apparently my body was adjusting with no trouble.
From an evolutionary standpoint, it all makes sense, of course. Paleolithic hunters almost certainly had to go without eating now and then, and if missing a few meals meant their hands were too shaky to toss a spear accurately, they’d miss quite a few more. We’re almost certainly well adapted to intermittent fasting, at least if what we eat day-to-day doesn’t mess up our ability to mobilize body fat for fuel when we need it. I couldn’t get by on Slim-Fast because I was an insulin-resistant sugar-burner consuming little cans of liquid sugar for meals. Not enough sugar to get me through the day, and I couldn’t release fatty acids quickly enough to make up the difference.
I went to bed after midnight and slept like a rock. I was hungry when I woke up this morning, but the feeling went away after my first big cup of black coffee. I finally began to feel really and truly hungry around noon, which was the 36-hour mark. Fortunately, my wife had saved a ribeye steak from the dinner she served the girls last night. I ate about half the steak and a cup of her delicious chili, which is light on the beans and heavy on the ground beef.
I don’t know if I’ll ultimately continue intermittent fasting once per week, twice per week, or get bored with it altogether and stop. But since it was nowhere near as difficult as I anticipated, I’ll give it a shot for now. I’ll keep you posted on the results.