Intermittent fasting has become one of the most popular “diet” trends on the internet.  For me, vegan intermittent fasting is a lifestyle not a diet, however, since it is not about calorie restriction or deprivation.  Vegan intermittent fasting is simply about changing when you eat (not what – or even how much – you eat).  And intermittent fasting can not only help you lose weight and burn fat, it can also improve your health AND save you time and money.

As a vegan, I initially thought intermittent fasting was only for those on a keto or low carb diet but I was happy to learn that vegan intermittent fasting was not only possible – it was also very beneficial.  But I had a lot of questions.  Here are some of the questions I first had when I first started vegan intermittent fasting.  I hope they are helpful to you too.

FAQ #1: “Is vegan intermittent fasting even possible?  Don’t you have to restrict carbs and eat a lot of fat and protein?”

As a low fat, high carb vegan I have not found this to be true at all.  I have enjoyed all the benefits of vegan intermittent fasting simply by changing when I eat, not what I eat.  And I eat a lot of carbs!

This question is common because many of the people who first popularized intermittent fasting were in the keto diet world. By restricting carbs (including healthy fruits, whole grains, and beans), keto and the Atkins diets put your body into a fat-burning state called “ketosis”.  Ketosis IS a healthy state for our bodies to be in. However, forcing our bodies into ketosis by restricting carbs is not healthy or sustainable in the long term.

Intermittent fasting also puts your body into ketosis.  However when you intermittent fast, your body goes into a natural and healthy state of ketosis.  And restricting carbs is not required! A low-carb diet is NOT necessary to get ALL the benefits of vegan intermittent fasting. Your body needs healthy carbs – including vegetables and fruits and beans, whole grains, and starches!  These are all healthy….and your body and brain thrive on them!  

FAQ #2: Which intermittent fasting method is best? How long should I fast?

The best intermittent fasting method is the one that feels best for your body and fits your lifestyle.  Only you can decide….nobody else should.

The three most common ways to intermittent fast are:

Time-Restricted Eating (this includes the popular 16/8 method) 

• This is the most common form of intermittent fasting
• In this method, you fast for a specific number of hours daily (and this includes the hours when you are sleeping – because you are technically fasting while you are sleeping) and then you eat all your meals within a specific number of hours.
• So for example, if you are doing a 16:8 fast, you are fasting for 16 hours and then eating all your meals within an 8 hour window of time.
• Some people fast for 12 hours, and then eat all their meals within a 12 hour window (this is really the MINIMUM one should fast to start to see benefits).  Some might fast for 17 hours, and then eat all their meals within a 7 hour window.  Typically the longer the fast, the more benefits.  But again, only YOU can decide what works best for your body, your goals, and your health.

OMAD (or One Meal a Day)

• In this method of Time Restricted Eating you fast for up to 23 hours and eat all your calories for the day in “one” meal – typically within one hour
• Some intermittent fasters consider a 20 hour or longer fast OMAD – and then enjoy a few courses as their meal (such an appetizer, dinner, dessert) over a 3 or 4 hour eating window
• OMAD may offer increased fat burning and health benefits.
• Eating only one meal a day can make it more difficult to ensure you are getting enough macro and micronutrients. It may also be more difficult for your social life or if you have a family. And it may not be ideal for endurance athletes. So OMAD is for experienced Intermittent faster only.

The 5:2 diet

• In the 5:2 method, you would eat normally five days a week (so any number of meals a day, whenever you like) and then you would fast for 2 days a week. SO for two days out of the week, you are fasting and not eating at all.
• Another option of the 5:2 method is to not completely fast on the fasting days, but rather limit calories to just 500 on the two “fasting” days. Some people find that a small meal on their fasting day makes the 5:2 method easier, others find that eating limited calories makes it more difficult to stick to (and this is likely due to the release of insulin when eating).

FAQ #3: What can I eat/drink while I am vegan intermittent fasting?

When I first started intermittent fasting, a trainer that I follow on Instagram said it was ok to have “up to 50 calories” while fasting, as this would NOT break a fast. SO (in other words) it was ok to have the pre-workout drink she was selling.  So I did (because it was delicious!).  What I did not know at the time was that drinking this pre-workout drink made intermittent fasting MUCH harder – and this has to do with how our bodies release insulin with even the smallest amount of flavored anything….and this insulin can trigger hunger, making the fast much more difficult.

I didn’t know at the time that it was the pre-workout drink that was making the fast difficult…I just thought intermittent fasting maybe just wasn’t for me. But I don’t give up that easily. I then read the book Delay Don’t Deny by Gin Stephens and learned about “clean fasting”. I highly recommend this book, as well as Fast.Feast.Repeat., also by Gin Stephens (both are available on Amazon).  From these books I learned that if you want all the benefits of fasting, you must “clean fast”….and this advice has proven true for me!

Clean fasting means that while you are fasting, you only consume the following:

• Water (plain or sparkling UNFLAVORED) – with NOTHING added (NO lemon, lime, etc)
• Coffee or Tea (black or green UNFLAVORED) – with NOTHING added (NO sweeteners – even 0 calorie sweeteners are off-limited – no creamer – nothing!)
• Electrolytes (i.e. salt, magnesium, potassium) – UNFLAVORED

In other words….

• Anything FLAVORED (even if it’s “sugar-free”) will break your fast.
• Diet drinks will break your fast.
• Flavored waters will break your fast (yep….put down that Tangerine La Croix).
• A splash of oat milk in your coffee will break your fast
• Anything with calories (doesn’t matter if it has 15 or 50 calories) will break your fast.  

Anyone who tells you otherwise is likely selling something or was told it’s okay by someone who was selling something. You will hear/read that you can have this or that BUT why risk breaking your fast – and ALL the benefits of a fast?

One trend in the ketogenic/carnivore intermittent fasting world is adding butter or fat to coffee.  This WILL break a fast.  And common sense says why would you want to add MORE fat to your body when you likely have fat ON your body to burn?  Your body will go right to burning up the fat you just had in the coffee as fuel, versus burning excess body fat.  Some will say adding fat to coffee makes the fast “easier”.  The BEST way to make the fast easier is to CLEAN FAST.

So….your intermittent fasting mantra should be: When in doubt, leave it out.   

FAQ #4: What about toothpaste while I am fasting?  Will using toothpaste break my fast?

Toothpaste is used in such a small amount and not consumed/swallowed (at least it shouldn’t be!), so it should not break your fast (unless you eat the toothpaste….or swallow gobs of it). Unlike drinking or eating unapproved foods and beverages during your fast, toothpaste is in your mouth for such a short period of time your insulin should not be affected enough to break your fast.

If you are concerned, one option is to brush your teeth with baking soda instead of toothpaste.

FAQ #5: Won’t I be hungry all the time?

You will likely feel hunger when you first start fasting.  This is NORMAL.  Your body is used to being fed at certain times of the day.  And when you don’t feed it on schedule it will growl.  That growling is the hunger hormone ghrelin – aka “growling ghrelin” – kicking in, trying to get you to eat. This hunger is temporary. Your body is becoming what is called “fat adapted” – it is being “trained” to burn excess fat as fuel, instead of demanding food all the time.  Allow this to happen…let ghrelin growl!!

As you become fat-adapted with consistent fasting, you will feel less hungry.  To help get through the hunger and growling stomach, drink water or black coffee or tea, and distract yourself.  Your hunger will soon pass….and you can satisfy it when it is time to break your fast and eat!

FAQ #6: I am pregnant/nursing/trying to conceive, can I intermittent fast? 

Intermittent fasting is NOT recommended for women who are pregnant or nursing. If you are trying to conceive, please check with your doctor before intermittent fasting.  In a Pub Med study (link here), obese women with PCOS (polycystic ovary syndrome) who fasted regularly, saw increased levels of luteinizing hormone, which is aids in ovulation (see the references section of this course for a link to this study).  But once again, please check with your doctor before starting intermittent fasting.

FAQ #7: Can someone with Type 2 diabetes intermittent fast? 

If you are diabetic, please check with your doctor before starting intermittent fasting AND before stopping any medications. I recommend reading the book “The Diabetes Code: Prevent and Reverse Type 2 Diabetes Naturally” by Dr. Jason Fung to learn about the benefits intermittent fasting can have on preventing and reversing Type 2 Diabetes, and then discuss this book with your doctor.  

FAQ #8: I’m on prescription medication, will it break my fast?  Will my supplements/vitamins break my fast?

Do not stop taking prescription medications due to your intermittent fasting schedule.  When it comes to prescription medications, please check with your doctor or pharmacist in terms of WHEN you should be taking your medication.  Some medication needs to be taken on an empty stomach, others with food.

When it comes to supplements and/or vitamins, some will break a fast.  When possible, take supplements and vitamins during your eating window (many even work better with food!)

FAQ #9: Will I get enough nutrients while vegan intermittent fasting?

Intermittent fasting is not a diet….and it is not about restricting calories.  You are simply eating your meals in a shorter window of time.  You should always try to eat a daily variety of whole foods – plant-based proteins, fruits and vegetables, whole grains, healthy fats.  

A good multi-vitamin can be beneficial (I love the Deva brand vegan multivitamin available here on Amazon).  And most plant-based doctors recommend the following supplements at a minimum (whether you are intermittent fasting or not):

• Vitamin B12
• Vitamin D3
• Vegan Omega-3 DHA/EPA.

FAQ #10: Can I work out while I am fasting?

Yes!  One of the biggest benefits of intermittent fasting is fat burning, and when you add in exercise while fasting, your body has to accelerate fat burning just to FUEL you.  And stored fat is steady energy.  No more pre-workout drinks are needed (think of all the money you’ll save).

When you are new to intermittent fasting, however, working out in a fasted state can be challenging. Your body has not yet adapted to this new way of thriving.  So take it slow.

Another exception is endurance workouts and long-distance running.  EveryBODY is different, so you will need to figure out what works for you in terms of nutritionally supporting endurance activities while living this lifestyle. As someone who has run marathons and half-marathons, I found my endurance and energy while running improved while in a fasted state….however, at a certain distance, (typically for me – after running 6 – 7) I noticed a decline in energy.  I recommend having food or a runner’s supplement (such as Gu) with you at all times if you run or attempt any endurance workouts while fasting.  And make sure to stay hydrated – electrolytes can be particularly helpful while fasting. 

FAQ #11: Won’t my metabolism slow?  I was always told that we need to eat every few hours to keep our metabolism fired up.

When you eat food every few hours, your body must release insulin every few hours. Having high levels of insulin in your body makes it very hard to lose weight, AND your body never gets a chance to efficiently tap into its fat storage.  

Because of the metabolic changes that happen in your body when you intermittent fast, your metabolism will INCREASE. With consistent intermittent fasting, your body will learn to burn excess body fat as fuel.  This is a HEALTHY way to burn fat and to lose excess weight.  

FAQ #12: I’ve always heard that breakfast is the most important meal of the day.  How can intermittent fasting be good for you?

Did you know that there are actually no studies that prove that breakfast is the most important meal of the day?  This myth was actually started by Dr. John Kellogg (of Kellogg’s cereal) and James Caleb Jackson (the inventor of dry cereal).  It was a marketing campaign for Kellogg’s Cereal.  

Breakfast = break-fast….you are breaking your fast after sleep.  So breakfast IS the first meal of the day….there are no rules as to when it should be eaten.  You can fast until noon and then break your fast however you prefer!

Disclaimer: Results may vary. The information contained on this page and this website are for informational purposes only. No material on this page on this website is intended to be a substitute for professional medical advice, diagnosis, or treatment. I am not a doctor.  Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen such as intermittent fasting, and never disregard professional medical advice or delay in seeking it because of something you have read on this page or this website. Please read the full Medical Disclaimer for more information.

This post contains affiliate links for which I may earn a commission (at no extra cost to you) should you make a purchase. As an Amazon Associate, I earn from qualifying purchases. Please see my Terms and Conditions for more information.

I hope this article was helpful and answered some of the questions you may be having about vegan intermittent fasting.  You might also find these articles helpful:

How To Break Your Intermittent Fast – Delicious Plant-Based Smoothie Recipe

Vegan Intermittent Fasting – Reasons to Intermittent Fast as a Vegan

Will Bloating on a Vegan Diet Ever Go Away?  10 Causes and Remedies