What is intermittent fasting? Does it work?

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A few years ago, I read a book called Food Rules, by Michael Pollan. It’s several dozen food wisdoms, collected from tradition and science. One of the things that stood out was his ultimate takeaway: eat whole foods, mostly plants, and don’t eat all day, every day (I’m paraphrasing).

Basically, try out intermittent fasting every once in a while.

Studies continuously show that various forms of fasting are helpful for a myriad of reasons, from fat loss to immune system improvement.

I already believed in focusing on a mostly whole food diet, and I believe, even in ketosis, that plants are highly important, but this last bit intrigued me.

Eating less is obvious for energy balance, as you can’t really lose weight if you’re taking in more calories than you’re expending, but cutting down how much I eat in general? Is there more to this?

Turns out there is!

Fasting, the willful choice to eat less food, is a practice that is prevalent in a lot of religions and cultures, but as I said before, it has a lot of practical applications to someone trying to improve their health.

So what is intermittent fasting?

There are multiple types of intermittent fasting, and most people are familiar with one in particular: sleep.

When we sleep, assuming we’re getting our 8-ish hours, we’re going a fairly long period without eating and this of course is where the term “breakfast” comes from (you’re breaking your fast). Mind blown, I’m sure, but intermittent fasting is basically taking that period of not eating and extending it. By depriving our bodies of calories from food for longer periods, we force it to run on stored energy. At first it wants sugar, so it gobbles up whatever free-floating blood sugar we have. From there it goes to stored glycogen in the liver and muscles, but once we’ve gone for about 24 hours without carbs, our body switches to ketosis. This is the basis of low carb diets, a state in which our body breaks down fat into ketones, an alternative energy to sugar.

Without getting into the minutiae of ketosis and ketones, our focus here is that intermittent fasting shines brightest while paired with a ketogenic or mostly ketogenic diet. When your body is fasted, it will HAVE to burn fat for fuel, increasing metabolism and mental clarity. If you’re cutting back on your carbs during a fasted period, your blood sugar remains stable, making it less likely that you’ll have the jitters and weakness associated with not eating, nor will you have the voracious hunger that comes with massive amounts of circulating insulin.

So there’s definitely benefits to not eating for an extended period of time, once your blood sugar is more stable (as always, I suggest giving up sugar as your first step to fat loss and good health).

Getting ready for an intermittent fast is pretty easy, but a few quick rules to follow:

  • Don’t eat anything with calories during the fast. You might read online that if you don’t eat over 50 calories, then you won’t break the fast, but even if this is true, it’s not worth messing around with. In particular, there is some mythology surrounding being in ketosis and ingesting pure fat; that somehow the calories you’d get from bulletproof coffee (coffee with coconut oil, grass-fed butter, etc) won’t break your fast. It almost certainly will. Best to stick to water, black coffee, and tea and don’t add anything to them.
  • Start preparing for your fast by stopping your eating at a specific time. If you’re living a traditional 9-5 work life, then not eating after 8pm, and not eating again until noon the next day, is the typical intermittent fast and the easiest to get into, as most of the fast is spent sleeping.
  • Avoid working out in a fasted state until you’re used to doing it. This could be any length of time, but again, being in ketosis will help minimize the hunger and low blood sugar jitters you get from not eating. While working out in a fasted state is great for fat burning, initially it will cause you nothing but insane, ravenous hunger, making you miserable during your fast.
  • Drinking water helps keep the hunger pangs at bay, and coffee helps blunt them, too, but too much coffee on an empty stomach can have the opposite effect, or exacerbate jitters.

With this in mind, there are several different ways to implement a fasting schedule:

16/8 – This is probably the most common and easiest intermittent fasting schedule to undertake. Essentially you’ll not eat from 8pm until noon the next day. After that, in the next eight hours, you’ll take in all your calories for the day, then resume the fast at 8pm. I have had great progress with this type of fasting, and once in ketosis, I am so focused and clear-headed in the mornings that I really don’t have a need to eat, nor the desire.

20/4 – Exactly as it sounds, it’s an even more extended fast. The idea is the longer you’re fasted, the longer your body is required to burn fat for energy. This increases insulin sensitivity which helps regulate type 2 diabetes among other metabolic issues.

23/1 – Even more intense than the previous options, this is essentially eating one meal a day, which is often 1200+ calories.

Protein-sparing modified fast

Developed to help the morbidly obese lose weight rapidly, professional bodybuilders and other athletes may often turn to this type of fast in order to shed a lot of weight in a short time. It’s a near total fast of food for several days, with only enough protein administered to spare muscle breakdown, along with electrolytes, vitamins, and minerals. For the most part, a PSMF should be carefully administered or observed, and isn’t recommendable for people who aren’t trained professionals, or under the supervision of trained professionals.

Egg Fast

A buzz concept among low carbers, egg fasts are basically what they sound like; an intermittent fast that is broken by eating only eggs and fat. The purpose is often to jump-start weight loss or to push past a fat-loss plateau. The configuration is 1 egg and 1 oz of fat (butter, mayo, etc) at a time, with an optional addition of 1 oz of full-fat cheese. Do this 4-6 times throughout the day. There’s a lot of ritual to the egg fast, but essentially you’re eating very, very low carb, very high fat, and moderate protein, so this “fast” isn’t drastically different than were you eating bacon and only bacon for 5 days straight. Still, there’s a lot of anecdotal evidence that suggests an egg fast is worth trying to break a stall or kick-start your metabolism into fat burning mode.

No matter what your reasoning for trying out fasting, there are many benefits, both in weight loss and overall well-being. In addition, it helps break the mental crutch that you NEED to eat, even if you’re not hungry.

I do some of my best, most focused work when my stomach is grumbling, but then I realize I’m mentally clear, not shaky, and full of energy.

Yay fasting! Give it a try – it’s free and pretty good for you, not even air can say that half the time.

Have you ever tried fasting?



    • Monechetti Reply

      I did my first 24 hour fast yesterday, mostly just to say I’d done one. I’ve read that after 16 hours, it’s really not any more useful in terms of the health benefits fasting provides. That said, it’s kind of cool to know that I was able to stick it out.

  • Austin Reply

    I might give that 16/8 a shot some weekend. I’d have to plan my run to end close to noon, though, because I will need the calories once I’m done…

    • Monechetti Reply

      I do fasted cardio when it’s warmer and I can run outside, but I start lagging hard after 2 miles unless I’ve been in ketosis for a month or more. How far do you typically run per day?

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