[The Fast Life] Introduction

I am not going to eat for 7 days.

But won’t you die?

Let’s say you are stranded in the desert for a week with no food or water. How long would you last? Google says it’s just over a week but that’s mostly due to dehydration. If you were near a water source you’d fare much better. In fact a one Mahatma Gandhi famously starved himself for 21 days on three separate occasions as a form of protest. David Blaine more than doubled that when he spent 44 days in a glass box in 2003. Though impressive, these feats are completely dwarfed by a man simply referred to as Patient A.B.. Patient A.B. stopped eating on June 13th 1965. He ate his next meal June 30th 1966. No, that was not a typo, this man literally didn’t eat for 382 days! Medically supervised and only provided with water, nutritional yeast, multivitamins, potassium and sodium, Patient A. B. lost a total of 276lb during the fast, going from 456lb to 180lb and perhaps more astonishingly only put back 16 of those pounds in the next five years. How did he do it? Well for starters his initial weight definitely played a big factor.

We take food for granted now, but believe it or not there was no Uber Eats for protohominids. If you couldn’t find food, you died. If you happened to develop a random genetic mutation that helped you survive a famine, then you passed it on to the next generation of famine survivors. Fast forward to today, your body still holds much of the evolutionary baggage of our ancestors. Our body has built-in mechanisms to help you survive a famine. You may not like them, but your love handles are one of them. Ketones are another one, but I’ll get to that later. Fat literally gets stored for this purpose alone, so why not take advantage of it? I’m not trying to kick the British out, I’m not trying to kick the bucket. I’m just doing it for, you know, kicks.

But isn’t it going to suck?

No. Well, it shouldn’t in theory. The reason why skipping a meal feels terrible is because there is not enough glucose getting to your brain. This is why you can find yourself on occasion desperately fiending for that next carb fix. But I won’t have this problem. I have already been doing intermittent fasting (only two meals a day) for probably the last four or five years and full day fasts on occasion. My body is already quite adapted to going long periods of time without carbs so I shouldn’t get the regular headaches, light-headedness and “hanger” pangs of a typical 3-mealer. Or at least, it should be minimized in intensity and duration. Also, I’m not just doing any regular old “water-fast” to “detoxify” my body. Not that there isn’t any psychological benefits to accomplishing seemingly impossible tasks using only your will power, but that whole process just sounds unnecessarily painful. Instead, I’ll be using hacks to get through the week with the aide of the combined knowledge of expert ketosis researcher Dom D’agostino and expert experimenter Tim Ferriss.

A quote from Tim Ferriss’ book on how he once did a medically supervised seven day fast the wrong way:

“…my lower back pain was so extreme that I remained on my bed in the fetal position…My kidneys were getting hammered by sky-high uric acid levels. My body was breaking down muscle tissue so the liver could convert it into glucose, and uric acid was a by-product of this. On top of this, since patients were limited to distilled water, nearly all the fasters (about 40 in total) couldn’t sleep due to electrolyte depletion and subsequent cholinergic responses (e.g., rapid heart rate when trying to sleep)”

Yeah… this is NOT what I want to happen. I don’t want to be in pain. I don’t want to be hungry. I don’t want muscle loss. I don’t want to deplete my will power reserves by thwarting the gaze of a jelly donut. There is a RIGHT way to do a week-long fast that will render it misery free.

Keys to Success

Be in Ketosis BEFORE the fast

If you need a refresher course on ketosis you can check out my blog post on the vast array of benefits or if you’re not into reading a wall of text whilst reading a wall of text here’s an ELI5: Your brain needs glucose (carbs) to run. If there is no glucose around, it can run on a glucose substitute called a ketone. If your brain is running on a sufficient amount of ketones then you are in what is known as a state of Ketosis. Being in ketosis has a host of benefits that can help me during my fast such as preventing muscle loss, cravings and hunger as well as keeping my brain sharp throughout. To get into ketosis you need to drain your body of it’s carb stores which is why this whole week I have avoided carbs and exercised throughout.

Reduce the adaption period

Unfortunately I will still probably have to face an adaption period while my body switches over to it’s new fuel source. In every anecdotal account I’ve read on the internet of people fasting, both experts and amateurs alike have said the same thing; the first 2-3 days are brutal. To quicken this process, Dom D’agistino recommends taking exogenous ketones during the first few days. Exergenerwhatt? Exogenous ketones are ketones that are made outside the body, specifically in a lab somewhere, and apparently offer the same benefits as the ketones made inside your body. The thing is, if your blood sugar is low then your ketones should be elevated to make up for it. However early on in the fast, your body is desperate for glucose so it may try to break your muscles down to convert them to glucose instead of manufacturing ketones. Though it did cost me a pretty penny, the KetoCaNa I bought should help get my body used to ketones and get me through this period.

Clear the schedule for the first few days

Just to be safe I made sure I don’t have anything important to do over the next couple days. This is why I lined this fast to start on relatively unimportant weekend. I can’t imagine going to work during the adaption period. I only hope I’ll get through it before Monday.

Stay active, but not too active

Tim recommends walking for 3-4 hours to elevate ketones and reduce the adaption period. He cites glycogen depletion for why this works better than high intensity exercise  but I have my doubts. Surely glycogen depletion is way faster in high intensity weight training than casual walking. I suspect walking brings out more ketones because low level activity burns fat rather than carbs and the lineup for free fatty acids going into the kreb cycle gets so long that some get re-routed for ketone production. Or at least that how I understood this Khan Academy video I watched once. I’m no biochemist so don’t quote me on that. Either way, it seems like it will be helpful so I’ll probably do a 3 hour walk the first couple days while listening to a podcast or audio book. During the week I’ll do 1hr walks and at the end of the week I’ll try to do a high intensity work out just to see what happens.

Keep vitamins and minerals in check

A common rookie mistake people who are on low cal, low carb, intermittent fasting and long term fasting diets make is that they don’t watch out for nutrient deficiencies. Specifically, when cutting carbs, a lot of people experience sodium, potassium and magnesium deficiencies. This results in the infamous “keto-flu”, which, from the accounts I’ve read online, seems like an absolute horrible way to spend the week. To avoid this I’m supplementing these 3 every day. Potassium in supplement form is heavily controlled and very hard to find. You need 2 boxes of spinach, 10 bananas or 45 multivitamins just to get your recommended daily intake of 3.5g. Instead I’ll be taking about a teaspoon of potassium chloride, which is usually used as a salt substitute. It tastes like drowning in sea water but it’s 100x better than not taking it so I guess I’ll just have to bite the bullet.


Fast Begins:

After my last meal, Friday 22nd

Fast Ends:

Anytime Saturday 30th


  • Water
  • Black Coffee with Stevia
  • Tea
  • MCT Oil
  • BCAA’s (max 4g/day)
  • Exogenous Ketones
  • Salt
  • Lemons
  •  Supplements
    • Fish Oil
    • Magnesium
    • Potassium
    • Multivitamin

Not Allowed:

  • Food
  • Drinks with calories


Before and After

Apart from the classic infomercial-style photoshoots I’m also going to be doing a DEXA scan at the start and end of my fast. The scan will give me an accurate reading of not only my body fat percentage but also my muscle tissue percentage. I haven’t read about anyone doing this for a full week fast so I’m really excited for the result. Specifically, I want to test if Dom and Tim’s claim that fasting the right way will result in zero muscle loss holds any water.

Daily Quantitative Measurements:

  • 6am
    • Weight
    • Waist Circumference
    • Blood Glucose Reading
  • 6pm
    • Weight
    • Blood Glucose Reading
    • Blood Ketone Reading

Daily Qualitative Measurements: (rated out of 5):

  • When:
    • Upon Waking
    • 10am
    • 2pm
    • 6pm
    • Before Sleeping
  • What
    • Focus: How easy would it be to write or read something for an hour right now
    • Restlessness: How antsy do I feel right now?
    • Eyelid Heaviness: How badly do I want to sleep right now?
    • Head Heaviness: How cloudy and heavy does my head feel?
    • Cravings: How bad do I have the munchies?


That’s all well and good but aren’t you worried about all the muscle loss?

While it’s true that a brain starved of glucose will look at all possible alternative sources, and that muscles are easily converted into glucose, it is unlikely for my brain to use my muscles as brain food for several reasons. Firstly, as briefly mentioned above, Ketones are naturally muscle sparing but I’m confident I won’t turn into a stick-man for another reason. If you don’t eat carbs then you can make your own substitutes out of ketones. If you don’t eat fat it’s okay because you have plenty to spare. But what about protein? You actually need protein to survive. Certain amino acids (the building blocks of proteins) are “essential” meaning that your body can’t make them. You absolutely need these for maintaining your organs and process throughout the body. Luckily, your body being the resilient entity that it is has come up with yet another famine fighting tactic known as autophagy. You thought humans came up with recycling? Think again. During autophagy your body cleans up damaged organelles and proteins and even dead bacteria and viruses that are laying around and basically recycles them for spare parts. According to autophagy expert Guido Kroemer, this process usually occurs 4 days into a fast and comes with various other benefits such as anti-aging and muscle building properties. This, coupled with purported claim that your mental clarity gets a significant boost by the 5th day makes me pretty excited for the end of the week, and I didn’t even talk about the weight loss. But first things first, I have to get through this weekend which I can only assume will be a hellish nightmare.

Wish me luck.


1 thought on “[The Fast Life] Introduction

  1. Pingback: [The Fast Life] Conclusion | Macrobatics

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