Re-feeding after a 3+ day fast: An Example/Guide

How I eat after not eating for days/prolonged fasting

“Any fool can fast, but it takes a wise person to break a fast” 

When I tell people I have done over a dozen long, multi-day fasts, ranging from 3 days to 7 days, they are usually shocked at how difficult it must have been. But on the contrary, the hard part was not the fast, the hard part was breaking it properly. I have broken the fast both ways, and the difference in the short term and long term is astronomical.

Let us dive in.

I’ll tell you this upfront, long fasts are EXTREMELY dangerous and should be done under the supervision of a medical doctor.  This is not medical advice and is only an example of what I do.  People have DIED after fasting for days to weeks and refeed improperly.  Proceed at your own caution.=

Goals

In breaking a fast, these are the goals I have. Everything done is based on keeping this in mind: 

1. Avoid refeeding syndrome/harm reduction 

2. Maximize “gut” well being 

3. Change eat habits after the fast 

Timeline 

First, let us setup a timeline. A good rule of thumb is that for any fast, it will take half as much time to get back to “normal” eating.  So if you fast for 4 days, the refeed period should take 2.

If you go 0-100 right away, you will likely have severe GI consequences.  This is not based on any randomized control trial but the general experience of people who fast. 

The first time I did a fast I ate ad lib and ended up having explosive diarrhea that could not be stopped.  Couldn’t even make it to the bathroom in time. 

Refeeding Syndrome 

Anyone who fasts must understand refeeding syndrome.  This is a SEVERE medical emergency. I have treated cases of refeeding syndrome in the hospital and it is not pretty.  They sometimes require ICU admissions to monitor their labs very closely. 

Simply, when someone goes a long time without food and suddenly re-introduces food again, the spike of insulin will cause shifts of electrolytes into the cell and out of the blood.  Since the person hasn’t had much food, they are already low on such electrolytes, mainly potassium, phosphorous, and calcium.  If these get too low, the heart can STOP.  This is no joke.  

Most people will not have an issue on a short fast, say 3 days, but it is still important to exercise caution. 

This is how:

1. Don’t binge eat and spike insulin like crazy to start

2. Replenish yourself with foods high in potassium, phosphorous and calcium   

Maximizing “Gut” well being

Gut health is a term thrown around a lot nowadays.  It is still amorphous and not clearly defined. We are still in the early stages of researching what gut health means and looks like.  What we do know is there are BILLIONS of bacteria living inside of us, and they have active roles in our health/disease. Without them, we could not exist.

For me gut health comes to down to the following phenotypically: The ability to eat foods comfortably with minimal symptoms bloating, constipation, diarrhea 

On a mechanistic level, this likely means the proliferation of good bacteria strains (probiotics) and the minimization of pathological strains.  Which strains are which are still being figured out, but we have some sense of this.  What we do know is that the modern, standard diet leads to a disadvantageous ratio of bacteria, even in zoo animals.

During the fast, the gut microbiome is likely undergoing dramatic changes. Bacteria are dying.  The ratio of certain bacteria is changing.  I attempt to encourage a more beneficial 

Changing Eating Habits 

Many people go into a fast hoping to learn to eat better after the fast than they did before.  I have refeed on ice cream and abject junk food, and guess what… I started to crave these foods more.  I believe that after the fast we have a CRITICAL WINDOW to reset how we eat.  Imagine you get to rewrite what you crave and don’t crave. This comes down to:

1. Possible changes to gut microbiome 

2. Resetting of reward centers in the brain associated with food

3. Changes in your palate and taste buds 

4. Alterations at the level of the hypothalamic weight set point 

When I’ve refed properly, I suddenly CRAVE ‘healthy’ foods and focus on eating them. I don’t even want to see junk food.  

How I break my fast 

With all that out of the way, this is what I do to break the fast. This is my routine for a 5 day fast:

First off, I start VERY SLOW.  This is both to all the problems stated above.  The first thing in my mouth is bone broth soup with some vegetables. You can almost feel the soothing effect of bone broth as it lines your insides.  Bone broth is rich in the amino acid L Glutamine.

This amino acid is associated with positive gut effects, especially as it comes to junctions between cells in your intestines. There is a giant discussion of “leaky gut” in the online health space, however we won’t get into that here.  If leaky gut is a real thing (which is seems to be), then having proper tight junction in the gut will help. L-Glutamine assists in this.  I  also supplement with it. Read more here.

After this bowl of bone broth, I wait.  Go for a walk. Get away from food.  I don’t want to become hyper obsessed with eating, especially after avoiding food for a few days.  I sit there and consume that bowl mindfully, without scrolling on the phone. I am incredibly grateful for it. This will set the tone for how I eat moving forward.   Eating distracted while scrolling on your phone is a recipe for over-eating 

Notice, I have yet to eat any probiotics or fermented foods yet. The gut may not be able to tolerate this right away, so I will introduce those after first giving it some glutamine.  

Next, after an hour or so, I will probably have another bowl of soup, coupled with some easily digestible fruits like dates.  Fruit is easy to digest and full of micronutrients.  Here I will also add coconut water, particularly on longer fasts as this is rich in potassium. 

This first day, I’m keeping my calories under 1000 cals.  I’m not going straight back to normal eating.  Metabolic rate likely has taken a hit during the fast, so I will ease my body into eating fully. 

For a 5 day fast, this is what calories will look like:

Day 1: 750-1000cals

Day 2: 1500-2000cals

Day 3: 2000-2500 cals

Keep in mind I weigh over 100kg and my maintenance is closer to 2800+ calories a day. 

It takes 2.5-3 days, half as many days as I fasted, eat normally again. The sneaky thing I do on day 1 and 2 is indulge just a little bit in some dark chocolate. There is no doubt that during the fast you will crave some sugar junk food, especially if you are scrolling on social media.  A bit of dark chocolate should satisfy this to avoid binge eating.  

The fruit and bone broth usually make up the majority of my first day. 

On day 2, this is when I start to optimize the gut for long term success.  Here I will re-introduce a plethora of fermented foods SLOWLY. A glass of kefir, some sauerkraut.  Different people will tolerate this differently, so need to start slow.  These fermented foods should provide the good bacteria that will lead to better gut health, whatever that means. 

During the fast the composition of different bacteria would’ve changed and I now get to eat things to manipulate that to my liking. Kefir with 12+ strains of bacteria such as L. reuteri and other lactobacilli should do the trick. 

By day 3,  I’m eating what my ideal, normal diet looks like but at a reduced caloric intake.  Meat can be introduced on day 2 or 3.  By now my gut should be ready for normal eating, albeit the new normal. 

In summary, my fast breaking philosophy:

1. Slow and calorie controlled 

2. Full of L-Glutamine rich foods to start

3. Full of Micronutrients and Electrolytes

4. Rich in fermented foods, but at a careful and timed exposure 

5. Careful indulgence to avoid binge eating 

Now this is what works for me and what works for others may be different. Absolutely do not fast without medical supervision, especially if you have other underlying medical issues. This is not medical advice, just what I do. 

After this is done, I have a fresh canvas on which to craft my dietary intake.  I can eliminate bad eating habits and have a new relationship with food.  I should have an easier time with weight/fat management.   IF prolonged fasting is beneficial (that’s a giant IF), I believe this effect is most important.  A reset of dietary intake, from the disease inducing standard American diet to a more thoughtful, goal driven pattern of intake. 

Drop your questions/comments down below.