Intermittent Fasting

Intermittent Fasting (IF) is a way of eating that can help you to lose weight, maintain a lower body fat percentage, and stay healthy. You may not necessarily see better results than traditional dieting methods, but for some people it’s much easier to stick to. That means that the results are much better in practice for those people. Many people, including me, also enjoy the occasional reminder that going a little hungry once in a while won’t kill you - a reminder of the privilege of regular food.

If you’re looking for another way to approach your diet, or you’re just curious about the whole process, it’s worth experimenting . There is some research out there that has found fasting can improve your health in other ways, but it’s early days so we don’t quite know the story yet. I’ll describe intermittent fasting for you and then go through what I have been experimenting with to give you somewhere to start.

Why am I talking about this?

I’ve been living in a little bubble for the past few months. It seems every person I follow on the internet who talks about fitness is talking about IF lately. My first dim awareness of anything to do with periods of fasting came from my parents a few years ago when they tried the ‘5–2 diet’. I started to experiment with fasting as a way to recover from my ‘cheat day’ and found it to be very effective. More on that later.

What is intermittent fasting?

IF isn’t a diet. Rather, it’s a way of eating that makes the timing of your eating more important than what you’re eating. You already do a fast every day while you’re sleeping. Generally that would work out to be somewhere between 10–12 hours of fasting depending on when you eat dinner. A common way of doing IF is to extend the sleeping fast to 16 hours, followed by an 8 hour feeding period. In practice, this means simply skip breakfast and eat two larger meals (i.e. the same amount of food you’d normally eat if you ate breakfast) later in the day. If you eat your last meal at around 20:00 (8pm) and eat lunch at 12:00 the next day, you have just completed a 16 hour fast.

This pattern of 16 hour fast, 8 hour feeding window is called a protocol. I’ll go into detail later about this particular one. Other protocols suggest extending the fasting window further, others have the window shorter. Some suggest doing the fast every day, while others (generally the longer fasts) are best done once a week or so.

IF protocols generally don’t dictate what you should eat, instead focussing on when. That said, if you have weight loss or other goals, what you eat during that period will make a difference to your goals.

Why fast?

James Clear sums up why you might like to try this in his [post about the subject] (sorry about the imperial measures):

Surprisingly, since I’ve started intermittent fasting I’ve increased muscle mass (up 10 pounds from 205 to 215), decreased body fat (down 3% from 14% to 11%), increased explosiveness (set a personal best with a clean and jerk of 253 pounds a few months back), and decreased the amount of time I’ve spent training (down from 7.5 hours per week to 2.5 hours per week).

James is of course training regularly already, and at 14% body fat, he was doing pretty well. I’ve noticed that there’s plenty of examples of IF working well with people who are already paying attention to this stuff. They’re adding IF to a pre-existing training regime, and usually they’re already eating clean healthy food. That said, there’s plenty of evidence to suggest that IF also works for people who aren’t training already (thought it really would help). You may be thinking “well obviously body fat would go down, because you’re eating less - you’re starving yourself!”. Not so. In fact, it works best if you eat the same amount of food you’d normally eat, only during the feeding window.

Fasting makes your day simpler. There are less meals to worry about, and when you try your first 24 hour fast, you’ll be shocked at how much extra time you have because you don’t have to cook/decide what to order, go pick it up, eat, or clean up.

I have also read that IF can promote autophagocytosis, which, as described by Wikipedia, is the natural, destructive mechanism by which unnecessary or dysfunctional cells digest themselves for other uses. This supposedly happens when fasting because the body is more likely to look for efficiencies within itself without a constant source of energy from you eating regularly. This process is destructive if left unchecked, but intermittently switching it on through fasting can help.

You’re convinced! But there will be doubters

IF is not the be all and end all. It’s just something else in your tool belt to help you meet your goals. It’s worth giving it a try, even if you end up deciding that it’s not for you.

You’ll probably meet a few doubters along the way. Rather than espousing intermittent fasting as the best thing in the world and getting into an argument, I suggest listening to their concerns. See if you can learn something from them. Be curious about why they think it’s a bad idea. You don’t have to act on their concerns, but you can learn a lot from listening to people that you don’t agree with, even if it’s just because they’re forcing you to explain yourself better. Here are some of the concerns I have come across with me since I’ve been doing IF.

Meal frequency


Isn’t it better to eat lots of smaller meals?

What about your metabolism?

Metabolic rate is increased when you eat because you’re digesting food. The theory goes that if you eat more often, you will increase your metabolic rate. However, this doesn’t seem to work in practice - if you eat more food at once, your metabolic rate will generally increase to meet the food you have eaten. There doesn’t appear to be any long term ‘increased metabolic rate’ benefit from eating smaller meals more often. That said, plenty of people lose plenty of weight by eating smaller meals more often - I’m not disputing that. If smaller meals more often works for you, stick with it.

Skipping breakfast?


Breakfast is the most important meal of the day!

There are plenty of reasons why eating breakfast is important. One of them is that insulin sensitivity is increased over a period of fasting, meaning that you are more hormonally prepared for breakfast than other meals. Since you are fasting while you are sleeping, for many people breakfast time is the only time this happens. The thing is, if you lengthen that fast, you increase the positive effects of insulin sensitivity. When you break your fast later in the day you have the same beneficial effects.

Hormonal effects of fasting

What I would consider to be extreme fasting can have significant negative effects. Like with extreme amounts of exercise, if you take it really far it can cause your body to be in a stressed state. Your body might stop the production of hormones like testosterone. However, this seems to happen when you couple intense training, lots of fasting (say, 2–3 full day fasts per week), and maybe some other stress in your life. I have heard some people espousing the benefits of extreme fasting, but they’re doing it under direct doctor supervision and taking plenty of precautions. That sort of fasting is not what I’m talking about.

Lack of information for women

Admittedly, in my own self experimentation I’m not incentivised to look for information for women, so it’s possible that I just haven’t looked hard enough. In any case, there seem to be a lot of questions about the benefits of fasting for women. I think there’s a bias towards information for men. For example, the negative effects of fasting (see above) seem to be much more pronounced in women. I don’t think they come on more easily necessarily, but from the small amount of information I’ve been able to fine, the effects seem to be more serious. Some tips I’ve found: - Women may see better results with a wider window of feeding (say 10 hours feeding, 14 hours fasting if using the daily IF protocol). - All [female page on Facebook] to help with IF.

Are the benefits really coming from fasting? Or is it something else?

It’s definitely possible that the weight loss benefits people are seeing are coming from the calorie equation - burning more energy than we eat. Comparing fasting to not fasting probably isn’t fair, because ‘not fasting’ really means ‘over eating’ in most cases. But the results are still there for the individuals involved, so if fasting is easier to stick to and it’s working, then don’t let this question stop you for now.

What I do

I have changed around my diet and exercise regime a few times in the last few years, but generally I can describe my lifestyle as active. I practice bodyweight exercise, and I’ve been dabbling in gymnastics for a while now. I have been eating a relatively low carb diet for over a year now with a ‘cheat day’ each Saturday where I eat a lot of carbs. On a Sunday, I would usually feel awful and bloated. This would often leak into Monday, plus I found I often had trouble with my eczema on Monday or Tuesday too. I did a bit of research on what other people did to ‘recover’ from their cheat days and came across the 24 hour fast.

The 24 Hour Fast

In summary:

  • last meal on Saturday night at around 21:00 (usually ice-cream!)
  • when I wake up on Sunday I consume 700ml of water. I drink water throughout the day including with each ‘meal’.
  • around 09:00 Sunday I consume:
    • glass of water with greens powder
    • 5mg of Branch Chain Amino Acids (BCAAs)
    • cup of black coffee
  • around 13:00 Sunday I consume:
    • glass of water with greens powder
    • 5mg BCAAs
    • cup of black coffee
  • if I’m struggling at 17:00 Sunday I consume:
    • glass of water with greens powder
    • 5mg BCAAs.
  • before bed (no later than 22:00) I eat a small snack. Note that this is the 24 hour mark. Examples of snacks:
    • a couple of pieces of tasty cheese
    • 2–3 celery sticks with peanut butter
  • Monday morning I resume my normal diet.

The BCAAs and greens powder help to make sure that I’m not depriving myself of essential nutrients, and honestly to help me get through it. In particular, they help guard against the cranky brain problem. I’ve noticed that as I’ve done the 24 hour fast more often, I am much less reliant on consuming the supplements and I have done at least one fast with only one serving of each.

I have found that the mornings are the most difficult. Once my body realises it’s not getting breakfast, the hunger goes away. The fog of the cheat day lifts by lunch time, and by mid afternoon I’m feeling pretty great. It’s a great time to do intense reading or writing.

The fast has helped significantly with my cheat day recovery. Once the fog has lifted at lunch time, it doesn’t come back. The weekly eczema flare ups that I was having have stopped (though my eczema hasn’t gone away entirely). Plus I’ve noticed I look a bit leaner in the mirror. Unfortunately I don’t have the capacity to measure that objectively so you’ll have to go with my subjective measure.

What’s bad about a 24 hour fast?

Sunday is a rest day for me, so I haven’t yet found myself trying to do a fast on a day where I’m required to do strenuous activity. I don’t know what would happen if I needed to be much more active. But I’ve managed to avoid it so far with a little bit of planning, and if I got stuck I could always eat something.

The more prominent issue I’ve noticed is the subtle negative social effects due to not eating. Eating with other humans is sharing. It can be upsetting to people if you’re not eating, so be prepared. Some people will also have opinions to share with you about what is healthy. Both of these things are manageable, but it can be a little daunting trying to explain why you’re not eating to your mother in law.

What I’d like to try next

16/8 hour fast/feeding window

This protocol is the one I used in my description of IF. It’s simultaneously one the more simple protocols, and one of the more complex ones. The version of this that was popularised by Martin Berkhan of [] goes into specific details about what to eat, including [carb] and [protein] cycling, specific timing for exercise, and specific supplementation. Exercising at the end of the fast pushes you deeper into the fast, and is followed immediately by the largest meal of the day to ensure muscle growth. Whilst I’m sure I will use elements of the Leangains protocol, I would like to start it off more simply.

The following is a daily protocol:

  • Upon waking consume 700ml of water. I drink water throughout the day including at least 500ml with each meal.
  • exercise in the morning at around 05:00, during which I consume:
    • 10mg of Branch Chain Amino Acids (BCAAs)
  • After exercise consume greens powder.
  • around 12:30 I eat lunch. Example:
    • properly prepared legumes (half a handful)
    • lots of baked vegetables (2–3 fists worth)
    • a protein (about 2–3 palms worth)
  • around 17:30 I eat a smaller snack.
    • Legumes (half a handful)
    • vegetables (1 fists worth)
    • protein (1 palms worth)
  • around 19:30 I eat dinner
    • Legumes (half a handful)
    • vegetables (3 fists worth)
    • protein (2 palms worth)

This protocol is heavily influence by my current work schedule, so it’s not perfect.

Fast Friends

My experiments with fasting are far from over. There’s plenty of great stuff about fasting, but it’s not the panacea. Intermittent fasting is another thing in your tool belt of things to help you get through this life with the body you have. The key to this is to keep experimenting and learning as much as you can. Try to uphold the value of active wonder in how your body works and how your actions (diet, exercise, lethargy, mediation, socialising) effect it. If you find something that works, that’s awesome. But be careful of creeping conservatism that makes you stick with things that used to work long after they’ve stopped. I didn’t write about IF to convince you to give up all you already know. I hope I sparked the curiosity in your mind, and I hope it carries through.