This is a copy of a post I wrote for Crossfit London on self-experimentation with intermittent fasting. 

I saw Andrew’s post up and I figured I’d pitch in. The reasons for fasting and the benefits we can leave to another post, but I’ve tested the following protocols and I wanted to share my experience. I also linked a really great PDF on the subject at the bottom of the post.

Personally Tested Protocols:

– Alternate Day Fasting as recommended by Eat Stop Eat. 24 hours without food but properly hydrating.

– 16 hour fasting/ 8 hour feasting window recommended over on Lean

– 20 hour fasting/4 hour feasting window recommended by “The Warrior Diet”

Clients and I have also tested and applied Alternate Day Fasts, 16 hour fasting/8 hours feeding  and came up with the “Sleep over Food” rule.

 Basic fasting guidelines:

– Fasting means “no food”, not “nothing”. Have plenty of water during your day. Coffee and tea are fine but don’t be a wuss and lace it with sugar, cream and god knows what. Man up and drink it straight. *COUGH Andrew COUGH* 😛

– Stay busy. As Kate mentioned, nothing sucks worse than being at home with a fridge full of food and nothing to do but think about it. The way the Western world experiences hunger is like a paper cut. Its sting is disproportionate to its physical impact. If you have something to keep you busy, you’ll forget about it.

– Be smart. If you’ve never fasted before, don’t think that it’s a good idea to skip breakfast before a big presentation at work. Also keep in mind, in fasting as in Crossfit, don’t make the mistake of thinking that “more” = “better”.

– Get off the sugar. Seriously. If you need a cookie every 3 hours to maintain blood sugar lest you kill someone, fasting 12 hours is going to feel like quitting smoking. Fasting gets much easier when your insulin isn’t all over the place. Go low carb for two weeks before you start fasting and you’ll make the transition easier.

Off to the protocols

Alternate day fasts:

Applicability: High

Sustainability: High

Difficulty: Low

What is it? Once a week, go 24 hours without food. You stop eating at 2pm one day, and you start eating again at 2pm the next day.

Reflections: There’s an adjustment period. For me, the problem wasn’t so much hunger, it was realizing how much external cues had an impact on me. I wasn’t hunger per say, but I was so used to eating at set times that at first it felt uncomfortable. It got easier and easier to do when I tried it over a few weeks. On the plus side, it’s easy to try, and gives you all the benefits of fasting without the guess-work. This makes it a great starting point for beginners. It’s also useful for more advanced crossfitters who may have over indulged in slightly too much cake on a cheat day and need to recover from insulin that’s all over the place.

 Lean Gains:

Applicability: Low to Medium

Sustainability: Low to Medium

Difficulty: Medium

What is it? Split every day into a 16 hour fasting window and a 8 hour feeding window, structured around when you workout.

Reflections: This fasting protocol was popularized by and produces some impressive results. If your life has a firm routine, it’s easy to apply. Too much variation in routine and it becomes problematic because of the importance of workout and meal timing in relation to total food intake and fasting window. If you can apply it, it works well for fat loss, and the supplementation recommendations help workout performance once you get used to it. It’s important to note that while the protocol does work when applied to crossfitters, for best results, you have to follow a strength routine on specific days.

 The Warrior Diet

Applicability: Low

Sustainability: Low

Difficulty: High

What is it? The Warrior diet recommends limiting your daily feeding window to 4 hours. (The book does suggest that hunger pangs can be off set with small servings of fruit or vegetables during the day, however caloric intake during a fasting period reduces the effects of the fast.)

Reflections: This method was possible as long as food intake during the feeding window was massive. However trying to apply it everyday becomes a problem, I became preoccupied with what time my feeding window fell in my day in relation to my last workout and my next workout. My preoccupation with food also rose considerably, as I became acutely aware anytime anyone was eating near me. While having one very large meal at the end of the day or right after a workout can be very satisfying this isn’t a practical protocol for day-to-day eating.

Considering the level of difficulty when compared to Alternate Day Fasts, I wouldn’t recommend this.

The “Sleep over Food” Rule

 The “Sleep over Food” rule isn’t a specific fasting protocol, it’s the idea that missing sleep is worse for mental/physical performance than missing a meal and prioritizing sleep. The meal you missed gets added to the next day’s food intake. I explained it a bit over here. The result is an unstructured fasting program, which works well if you’re already comfortable with fasting.

Thoughts on the protocols

Of the protocols I tested, the Alternate Day Fasts and the Lean Gains method were the best. While I currently don’t stick to the lean gains method meticulously, the principles behind it are sound and I tend to follow the suggested meal timing, supplementation pre-workout and macronutrient cycling. I tighten my adherence if I need to shed some fat, but once I drop enough it allows me to stay at low body fat without a substantial amount of effort.

I also use the Alternate Fast Day protocol regularly if I’m not training as heavily as I’d like, or to recover from eating like garbage *COUGH chocolate cake COUGH* to get my insulin levels back on track.

For an excellent review of the most popular protocols with accurate measurements and tips for how to begin fasting, check out this PDF from Precision Nutrition.