The 7 Cardinal Rules of Fasting For Weight Loss

Thankfully I am beginning to see more and more people adopt the healthy practice of fasting.

While it is has been around ages, we seem to have been brainwashed to believe that eating at all times is necessary for our survival.

Hungry? Quick! Here’s a 100 calorie snack, a protein bar, a sandwich, a triple grande coffee with whipped cream. Just eat anything. Anything I say! We need to curb that hunger… and fast!

Hunger, panic, and pandemonium have become  synonymous. You can’t just be hungry, you’ll get hangry.

I call bullshit.

Fasting is an awesome way to detox, cleanse, gain mental clarity, and reverse hormonal irregularities associated with insulin and obesity.

However, I do also see a lot of people can fall short with fasting — they get symptoms they are not familiar with, don’t know when to stop their fast, and have been conditioned through marketing geniuses to be afraid of hunger.

All fasts, whether a short daily, or longer duration all have some common strategies you can employ that will help foster a postive experience with fasting.

Perhaps most importantly, these strategies will ensure you continue to engage in a fasting practice regularly.

In this article I discuss the common troubleshooting issues, and how to understand how to listen to your body.

1. Drink Liquid. A Lot of It.

During any fast, an uptick in water and herbal tea consumption is essential.

We are primarily made up of water (around 80%), and typically derive around 20% of our water intake from solid food. During fasts, be it daily or longer, we must actively replace the water derived from solid food.

Very generally, aiming for 3L of water daily will capture most people’s water requirements, but this number can vary. Flavoured water works too. Lemon, cucumbers, lime. Get creative and make it work for you.

Bone broth is a lovely addition to water consumption and has a beautiful cacophony of cartilage, marrow, and essential electrolytes. With long term fasting, any loss of minerals can be replaced with bone broth. It is great for immune function, the spine, and nervous system health.

A good sign you are getting enough water is if you are excreting a pale yellow, or even clear coloured urine.

2. Expect Electrolyte Loss

One of the most encouraging, at least from the patient’s perspective, initial signs of fasting is the rapid drop in weight.

When insulin levels fall, the kidneys excretion of excess water will result in a rapid loss of water weight. Along with it, there will be potential electrolyte losses in Na, K, Mg and Cl.

In obese patients, this is a great thing. They typically already have an already high extracellular concentration of sodium and potassium, hypertension, and frig, they are just uncomfortable.

In this study, the authors looked at the patterns of sodium and potassium excretion with fasting:

Notice the rapid increase in potassium and sodium excretion in the first 5 days of fasting. Equally as interesting is the preservation of potassium and sodium after the 5 days.

A nod towards our never ending quest for homeostasis.

You just don’t continue to excrete sodium indefinitely. Your body knows better, and so the conservation of said electrolytes happens around the 5 day mark.

With a rapid drop in electrolytes, as we often see in patients adopting a high fat, low carbohydrate diet, a myriad of unpleasant symptoms can show up. Commonly nicknamed the keto flu, these symptoms can last anywhere from 3 days upto 2 weeks.

Some people do not experience this at all, some experience one or two symptoms, and others can experience the entire symphony of unpleasantries.

Keto Flu can look like any of the following:

Low or unstable energy
Muscle cramps
Gas and bloating
Brain fog
Poor mood and ability to focus
Loose stools/diarrhea

The good news is it is almost entirely avoidable and NOT a necessary rite of passage to ketosis.   If you are experiencing these symptoms, it is akin to a sugar detox, and you are beginning to use fat as your fuel.

Most often, these symptoms are just related to electrolyte imbalances or deficiencies of potassium, calcium, sodium, or magnesium.

Yay for fat adaptation!

The quick fix and way around these symptoms can be achieved by drinking bone broth, taking an electrolyte supplement.

Or you can…

3. Consume More Salt Whilst Fasting

Yes. MORE salt.

One of the best strategies for regulating sodium is to eat more of it.

I recognize this runs contrary to what most larger health organization advocate for. But low levels of salt, have been linked to insulin resistance, which support the development of Metabolic syndrome, Diabetes, Alzheimers, and other neurodegenerative changes.

When you fast, there will be a natural drop in serum insulin levels, (obvs…there is no external stimulus (food) to mediate the response). As such, you will just naturally eliminate more fluids, and sodium.

Sodium is essential for life.

So here’s an easy hack for you. Dissolve ½ tsp of sea salt in a big glass of water, and drink up. This should mitigate most “flu-like” symptoms.

And if you’re going to salt…do it with sea salt.  Sea salt is not manufactured and does not have fillers in it.

4. Caffeine

To caffeinate or not to caffeinate? I wonder if that was that the question Hamlet was truly pondering.

There are two basic camps on caffeine and fasting. The purists prefer black coffee, often unlimited, whilst fasting.

I wholeheartedly agree with this…some of the time.

For a morbidly obese patient, this makes perfect sense. At mere calories per cup, it won’t have a large effect on insulin levels, and patients will benefit from the metabolic stimulation and the rich source of antioxidants in coffee.

This pure fast will deplete stored glycogen quickly, and tap into visceral fat stores for energy. Which is CRUCIAL to course correct visceral obesity.

Visceral adiposity is one of the strongest predictors of longevity, and reducing it should be sought to correct immediately.

For someone who is not morbidly obese, I will often recommend coffee with a high fat content, such as coconut oil, with grass fed butter. This is often called a butter, or bulletproof, coffee.

I am partial to a cup of fat in coffee in the morning for a couple reasons:

1. Our neurology is such that we are in our peak cognitive state for performance and productivity between the hours of 9am-1pm.

This is your brain’s peak state for learning, remembering, and producing. As such, it is highly advantageous to feed the brain a fuel source it both requires and expects for best performance – fat. As it is peak state, It is also the most energetically taxing time for your brain.

Ever feel like your energy tanks around 2pm? This can be a myriad of things, but in the context of brain health, your brain likely needs a top of energy. If you are consuming stable, clean burning fat as a fuel source, this dip can be avoided.

Oh, and it is delicious.

2. Feeding yourself stable clean burning fats, as an energy source has minimal, if any effect on insulin, and allows for your body’s fat stores to provide a rich energy stream to assist you.

Which is the game we are after, no? Stored fat on the body being used.

Sign me up, baby.

5. Stay busy

A watched pot never boils. If you are checking your watch, painfully waiting for the fast to be over it…it never will.

Get a book, dive into a project at work, go for a walk, exercise, spend some time doing what you love.

Don’t look at pictures of food, or other food cues like cooking, smelling food, watching cooking shows, or listening to food being cooked.

These will basically elicit a Pavlovian-like response that a meal is coming, and your body will begin to prepare for it, whether you are eating or not.

So don’t set up shop to work in a bakery all day, or all you’ll want is eclairs.

Whenever I want to do a 24 h fast, I always find it easiest when I am in the clinic. Along with serving patients and their necessary follow up, there are meetings, calls, interviews, etc. I don’t have time the proper time to sit down during the day for a meal.

It works perfectly to fast through the day:
1. I am not thinking about food
2. It still allows me to sit down and enjoy dinner with my husband and our children in the evening.

6. Listen to Your Body

One of the greatest gifts you can ever give yourself is the gift of listening. If, for example, you have set out to do a 72 h fast, and you are feeling awful and just not having it at 50 hours…then for the love of fat bombs…stop.

As a recovering perfectionist, I totally understand the need to achieve, to hit targets, and to produce.

I get it.

It is, however, more important to set the ego, along with its internal chatter, aside and listen to your body cues when you are fasting.

Lightheadedness, weakness, dizziness, disorientation, sleep disturbances, are all indications to break a fast.

Do not ignore what your body is telling you and do not force it.

There is nothing to say you cannot reattempt again in a week, a month, a quarter. Give your body the time and room for adaptation.

You’ll get there. I promise.

You don’t just show up to a marathon and run it. You train on endurance, consistency, recovery. You join a community of like minded individuals. Slowly, your running improves. The same is true with fasting. Or any health practice for that matter.

Take your time and heal thyself, doctor.

7. Understand Your Hunger

You will feel hungry during a fast.

This is normal. And temporary.

The hours around when you typically eat you should expect to hear more grumbling, and to feel the most hungry.

This feeling is a normal part of homeostasis to ensure you are being adequately fed. It is mediated through the hormone ghrelin. Ghrelin is secreted from the stomach when it is empty.

Think of ghrelin like a little gremlin that pops up and says time to eat!

Ghrelin affects brain function, which signals us to eat. Ghrelin targets the arcuate nucleus in the hypothalamis, which in turn has you rumaging through your pantry to find to chow down on.

Preprandial (before the meal) rises in ghrelin have been well documented.


Look at this graph. This is how that gremlin typically operates. Look at the black line – see the spike right before normal feeding times, (8am, 12pm, and 5:30pm)?

This is the surge in serum ghrelin levels that make you start thinking about food. Notice the immediately decline following the meal.

As this is response happens the brain, it can be argued that the longer you have had consistent eating times, the more hard wired this signalling and rise in ghrelin will be.

Neurons that wire together, fire together, as the famous saying goes.

However, and this is a big however, that predictable cycle of when you feel hungry can be totally disrupted with longer fast.

Check this study out. These guys looked at the rise and fall of ghrelin levels in subjects undergoing a 3 day fast.

What they found was participants ended up disrupting that rise and fall of preprandial ghrelin levels after engaging in a 72 hour fast.

In other words, once you work your way up to a 72 h fast, you won’t necessarily be hungry at the same times you were before the fast.

This is super cool news. It obliterates the common objections and fears I hear around hunger and fasting. Well doc, I’ve ALWAYS been a night snacker, so how am I going to get over that? I’ve ALWAYS needed something at 2pm, etc.

The pattern can be disrupted. Your body is adaptable. Give it the tools to create better rhythms.

A few other studies have looked at fasted ghrelin levels like this one and this one. They suggest that ghrelin levels are lower in fasted states than they are in fed states.

Goes against common thinking doesn’t it.

It would be logical to assume you would be hungrier with fasting and yet the reverse is true – your hunger levels drop with fasting.

And let’s just be honest – being hungry is annoying.

More often than not, it is the perceived fear of the hunger persisting that derails us, not the hunger itself.

The benefits of fasting are off the charts and pale in comparison to a grumbling stomach.  I’d take a temporary annoyance, at its very worst, to have a better brain, metabolism, hormonal balance, and better quality of life and vitality.

Being hungry is nothing to freak out about.

It is to be expected. And with time, will drop.

Big food companies would have you think you will turn into a raving lunatic at these signs of hunger.


The hunger passes. The hunger is temporary, and comes in waves. It is not like it is a speaker that just keeps getting louder and louder until you’re deaf.  Nonsense. Plus, as we have discussed, the pattern can be also be disrupted.

Just as neurons that wire together, fire together; neurons that fire apart can wire apart too.



Fasting is a best practice for weight loss, mental clarity, energy, and productivity. Troubleshooting the most common hurdles surrounding fasting will increase compliance and consistency over the long term.

There is a learning curve to fasting. Adaptation for frequency and duration of different fasting methods must be respected. Best practices include increased water consumption, electrolyte consumption, understanding hunger signals and staying busy.

One of my favourite things about fasting is it shows you what you are capable of, and that you are not dependent. It allows you to break bad habits, and let them die hard. As they should.

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