How to Fat Fast on Keto and why it might be right for you
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As part of the Keto Mini Challenges in 2021 we decided to follow Dr. Fung’s 3 Day Fat Fast followed by an extended 48 hour fast. This blog post will focus on the Fat Fast. Check out the separate post on extended fasting and how I ended up doing 100 hours rather than 48!
How does the Fat Fast work?
As you guessed it, you will focus on eating healthy fast during this diet. You might think that that will give you a long list of options, but actually, when following Dr. Fung’s Fat fast, your list of foods is very short.
What you can eat during the Fat Fast
Eggs
Bacon
Salmon, Sardines
Olive oil, coconut oil, MCT oil, avocado oil, macadamia nut oil, butter, ghee
Mayo (if healthy oil based)
Avocado
Olives
Spices without sugar
Leafy greens cooked in or covered in fat
That’s it. So yes, no dairy except butter. No meats beyond Bacon. No vegetables besides leafy ones like Spinach or Lettuce. You can use up to 3 Tbsp of heavy cream for your coffee if needed but if you can, don’t.
When it comes to fluids, you can have water, tea, coffee and bone broth.
Unlike during an Egg Fast, there are no quantity restrictions here. Eat until full. Over the days you might see that you’re getting less hungry.
What are benefits of a Fat Fast
As per Dr Fung, his fat fast can help you get used to fasting and regulate your hunger and cravings. It is a great way to ease into Keto or a Low Carb way of eating.
You do not have to be eating Keto or Low Carb to try a Fat Fast. Actually when Dr Fung tried it for the first time with a patient, he used it as a way to get his patient off carbs. While I did this fast for 3 days. The patient did it for 2 weeks!
Benefits you might see during a fat fast:
Reduced insulin
Reduced hunger and cravings as your body moves into Ketosis thanks to the highly reduced carbs
With the limited number of foods, you will get tired of them which in the future may also help with portion control
Possible weight loss with the drastic reduction in carbs
Meal plan for the Fat Fast
I continued Intermittent Fasting while doing the Fat Fast meaning I only eat between noon and 7pm. Here’s what my meals and snacks looked like while doing the Fat Fast and insights and learnings to follow after!
I always cooked with Butter and will not list that below
Day 1 - Fat Fast:
Lunch: Egg White Wrap filled with Bacon, Avocado, Eggs (2) and with a side of buttery Spinach and Bacon (Total of 4 slices)
Dinner: Eggs (2), Avocado as Guac’ and Bacon (5 slices)
Snacks: Bacon (3 slices)
Day 2 - Fat Fast:
Lunch: Eggs (2) and Buttery Spinach Omelet, Avocado as Guac’, Bacon (5 slices) to dip,
Dinner: Egg White wrap with Eggs (2), Bacon (4 slices), Buttery Spinach and a side of olives (~2oz)
Snacks: none
Day 3 - Fat Fast:
Lunch: Bacon (6 slices) with soft boiled eggs (2) and Buttery Spinach
Dinner: Bacon (3 slices), Ribeye (12oz) - (READ ON TO SEE WHY I ATE THAT - NOT PART OF THE FOOD LIST!!), Avocado and non-sugar containing Pork Rinds
Snacks: Pork Rinds
Fat Fast Snack Options
With such a restrictive food list, snack options are limited. You can eat the same as you would for lunch or dinner. For me, I decided on Day 2 to batch prepare bacon so that I could munch on that. I also got myself Pork Rinds that do not have sugar or maltodextrin in the ingredient list. This was great to get something crunchy. They aren’t explicitly listed in Dr Fung’s Food list but I gather that they are pretty much the same as Bacon. Hard boiled eggs are also a great option!
Why I ate a Ribeye on the last dinner
We had decided ahead of time that we would do a 3 day Fat Fast and then transition into a 48 hour extended fast. Given that on day 3 of the Fast I still felt like snacking and not fully full I decided to up my calories and fats and protein for dinner to set myself up for success on the extended fast. And booooy….read the separate blog post to see how I went WAY beyond 48 hours of fasting!
How did the Fat Fast work for me and others?
Similar to when I did my egg fast, carnivore fast and dairy free fast I tracked my weight while I was doing this, as well as level of Ketosis. I also observed hunger, sleep, energy and here are my results. Now, this is just me and further below I will share the experience of others too for a more complete picture.
I wasn’t going in with any expectation to loose weight, so I wasn’t surprised by my curve which pretty much stayed flat. Others did lose weight though so keep reading to learn more about them.
I also measured my level of Ketosis, Glucose and the resulting Glucose Keto Index (GKI). The curve definitely shows how restricting carbs put me deeper into Ketosis.
If you’re not sure how to interpret the above, do not worry. Here are some great infographics from Keto-Mojo whose measuring device I’m using:
Level of Ketosis - Yellow Line in my chart above. The higher the better
Glucose levels. Black line in my chart above. The lower the better.
Glucose Ketone Index. Grey line in my chart. The lower the better
If you’re curious about your levels I highly recommend buying a Keto-Mojo Device.
You can either get 15% off the Starter Kit ($44.99 to 49.99) by shopping through this link or get it on Amazon.
Lastly, I also tracked my Macros like I always do during fasts to ensure I have enough fat in my diet.
Looking back, this fast - for me - did not have enough benefits to do it again. Others in my group lost quite a few pounds though and it did help with cravings and regulating hunger.
I can imagine that if you do this when not eating Keto before, this will show dramatic results though!
How to transition after doing a Fat Fast for a few days
If I’ve learned one thing during the Egg fast, Carnivore fast and Dairy Free is that you should NOT just go back to ‘normal’. It’s important to transition slowly.
Now, with how we set this Fat Fast up with the Mini Challenges though, I did NOT end up going to a regular diet after Day 3 and instead moved straight into an extended water fast. More on this in the Extended Fast post.
In general though, if you do a Fat Fast I would suggest slowly reintroducing one veggie at a time and one meat at a time. On Day 2 of transition add some dairy and take it slow. Carry forward the Fat Fast foods for a few days and do 75/25 and then 50/50 before going back to your usual way of eating.
Also make sure to chew your foods well. Take your time when eating. It’s ok to take 20+ minutes to finish a plate.
My learnings with doing a Fat Fast for 3 days
After doing egg fasts, dairy free and carnivore, this fast didn’t seem that challenging food wise. I love bacon. I love avocado. Eggs are fine and I was able to have some vegetable with Spinach.
By Day 3 though I was very ready to stop the Bacon. I’m definitely not used to eating THAT much. I also had the following learnings:
Olives: I had no clue that Olives were 100% fat. No protein. No carbs. This makes them a great snack when you need to get your fats up.
Digestion: Everything was fine for me but I had friends who experienced constipation as well as some that experience diarrhea
Sleep: No impact. I slept just as well.
Energy: Fine, no change.
Every BODY is different! Once again, doing this with a group of people showed me how differently we all react. From people losing weight to increased energy and some feeling more satieted than others.
Keto & Fat Fast Testimonial
This Fat fast was part of a series of Mini Challenges I started on Instagram in which groups of people do these together, provide moral support and encouragement. Britt, also known as @love2lowcarb on Instagram led us through the Fat Fast and was happy to share her thoughts on it.
HUGE THANKS FOR TAKING THE TIME TO SHARE YOUR EXPERIENCE!
“I’ve always wanted to do a fat fast, and it really paid off! It’s amazing how real, whole foods can enable your body to feel satisfied, release weight, maintain energy & taste amazing. I never thought I would lose 2.2 lbs in 3 days of eating bacon, avocados and eggs, then turn around and easily fast for 46 hours, losing 4 more lbs. I may make this a monthly event”
Written by Britt, @love2lowcarb
Would I do a Fat Fast again? I don’t think so. Catch my write up of the extended fast to read why!
Am I glad I did it? YES! These different fasts have been amazing in showing me how my body reacts to different foods and I’m happy to report that my body is very happy with a high fat diet. I see a lot more Bacon, Avocado, Eggs and Butter in my future!
If you’d like support in trying something like a Fat Fast, check out my Personal Coaching!