What Is Clean Fasting And How It’ll Boost Your Fasting Results

clean fasting / 2 glasses of ice water on a wooden table

Last Updated on January 28, 2023 by Lori Geurin

When I first started intermittent fasting (IF), I’d never heard of clean fasting. I dove in headfirst and eventually learned that not all fasting is created equal. Gin Stephens says that clean intermittent fasting is the only kind of fasting, and after years of practicing IF, I agree.

So, what is clean fasting? Simply put, it’s avoiding any type of food or drink (other than water, sparkling water, black coffee, and unsweetened tea) during your fasting period. That means no calorie-containing beverages, bone broth, no foods, and no snacks.

Wondering how to do a clean fast? In this post, you’ll learn all about clean fasting and dirty fasting, plus the benefits and stages of fasting.

Intermittent fasting has been around for ages but has gained popularity recently. From weight lifters to those with chronic illnesses, many have discovered the power of fasting to improve their health, lose weight and reverse and prevent diseases.

A common question I hear is, what is clean fasting? Breaking down the clean fasting rules and comparing clean and dirty fasting is the focus of this post.

Get our FREE Intermittent Fasting eBook

free intermittent fasting ebook

I’ve been intermittent fasting for a few years and have experienced so many health benefits. In the past few months, I’ve tested the effects of clean and dirty fasting. Below I’ll share what I’ve learned using myself as a guinea pig. Hopefully, the results of my experiment will help you get the most out of your intermittent fasting journey!

This post may contain affiliate links. This means that if you make a purchase through one of my affiliate links, I may get a small commission at no additional cost to you. Thank you so much for supporting our little blog. I appreciate you!

clean fasting with black coffee

What Is Clean Fasting?

Clean Intermittent Fasting Rules

So, what is a clean fast? When I started intermittent fasting years ago, I’d never heard of clean or dirty fasting. But learning how to utilize clean fasting has improved my fasting game immensely.

Clean fasting creates the ideal fasting environment – one without any insulin spikes.

And one of the most significant benefits of clean fasting is that it makes your body a fat-burning machine. In truth, clean fasting is the way to go if you want to see the most success in your fasting efforts.

It includes only unsweetened, calorie-free beverages. But keep reading for all the details!

RELATED: 7 Ways to Stay Motivated When Fasting: Tips for Intermittent Fasting Success

Clean Fasting Foods / Clean Fasting Drinks

Wondering what clean fasting foods are? Well, I’m going to list them for you here. Below are the only foods and/or drinks proven safe to include during your clean fast.

This means that they won’t spike your insulin, and they’ll keep your fat-burning in overdrive, which is ultimately what you want.

  • Black coffee
  • Unflavored water
  • Sparkling water, mineral water, and club soda
  • Unsweetened teas (not fruit-flavored) – include herbal teas, green tea, and black tea
  • Salt and electrolytes
  • Medications prescribed by your doctor

Get our intermittent fasting how-to guide to learn all about IF!

How Do You Like Your Coffee?

In America, many of us add so many creamers and sweeteners to our coffee that it hardly resembles actual coffee. In fact, I’ve met people who say they hate the taste of black coffee, but they “love drinking coffee.”

I’m not here to tell you that you can’t put anything in your coffee if you want to, because sometimes I enjoy a little cream or coffee drink myself. But, if you want to improve your intermittent fasting results and are a coffee drinker, you must consider drinking black coffee.

What is black coffee?

It’s simply coffee with nothing else added—no creamers, sweeteners, etc.

I’ll admit that after years of drinking coffee with creamers and sugar, going cold turkey and drinking black coffee was a jolt to my system. Last year, on January 1, I set a goal to cut out all coffee creamers for the year. (With a couple of minor exceptions) I met my goal.

Doing this taught me that I could enjoy my coffee black. So if you’re wondering how to start drinking black coffee, set a goal for yourself, then go for it!

Right now, I’m doing black coffee Monday through Friday, and I’m enjoying a natural almond milk coffee creamer on the weekends. I’ve found that you have to make your fasting practice fit your lifestyle.

So, learn what works best for you and do that.

Need some inspiration for your fasting lifestyle? Get 42 powerful intermittent fasting quotes to motivate you.

RELATED: 11 Steps To Lose Weight Easily: Staying Motivated And Maintaining Your Diet

Learn about the intermittent fasting types.


clean fasting / woman doing pushups

What Is Dirty Intermittent Fasting?

Dirty fasting is when you consume foods or beverages that break your fast. Many experts will tell you dirty intermittent fasting is fine. And to be honest, I didn’t know there was a difference for years because much of what I read said you were still fasting as long as you keep your calories under 100 during your fasting window.

I would have my bulletproof coffee most mornings and still experienced the benefits of fasting, including better mental clarity, improved energy, complete elimination of my reactive hypoglycemia, and effortless weight loss of 20+ pounds.

Related: How Intermittent Fasting Cured My Reactive Hypoglycemia

But once I started practicing clean fasting, I experienced a noticeable boost in benefits and additional weight loss (bringing my total weight loss to 35+ pounds). So, if you’re fasting for weight loss and haven’t lost anything for a while, I’d recommend clean fasting for the best results.

Try it for a couple of weeks and see what you notice.

(Check out the complete guide to fasting here.)

Dirty Fasting Foods / Dirty Intermittent Fasting Drinks

Technically any food will break your fast, but the ones listed below are commonly referred to as dirty fasting foods.

They’re well-known culprits that people often add to their clean fasting foods that will spike your insulin and stall your weight loss, especially if you consume them daily, even in small amounts.

Here are the dirty intermittent fasting foods and drinks:

  • Coffee creamer
  • Cream
  • Flavored coffees
  • Flavored water
  • Food
  • Sweet or fruity teas
  • Milk
  • Almond milk or other plant-based milk
  • Artificial and natural sweeteners
  • Lemon slices
  • Collagen powder
  • Protein powder
  • Bone broth
  • Coconut oil, MCT oil, and butter
  • Sugar-free sodas
  • Sugar-free breath mints
  • Sports drinks
  • Some nutritional supplements are sometimes okay, depending on what they are, but it’s usually best to avoid them entirely within the fasting window, if possible.
  • Supplements including exogenous ketones, collagen, and BCAAs
  • Sugarless chewing gum

Now for an experiment…

My Clean Fasting Vs. Dirty Fasting Experiment

First of all, I’ll offer up this disclaimer to anyone interested: I’m not a scientist, and I don’t play one on T.V. I’m just a girl who loves intermittent fasting and occasionally geeks out over research, facts, and figures that might be helpful to others. Take this information with a grain of salt. The only test subject was me. However, this fact does not make the results any less compelling.

My experiment was straightforward and conducted for a couple of weeks. When comparing the results of clean and dirty fasting, I looked specifically at:

  • my symptom relief and the benefits of fasting
  • my ketone levels (how quickly I got into ketosis with fasting alone, not via a keto eating plan) or level of fat-burning

This post contains affiliate links. And you can read our Affiliate Policy here.

Now to the good stuff.

The Results And What I Learned…

  • Symptom relief and benefits of fasting – With clean fasting, the benefits I’d already experienced (with the prior dirty fasting) were heightened. I felt even more clear-headed, had better energy (something I continue to struggle with due to chronic Lyme), and felt no hunger. My brain was sharp, and I was more efficient. My body saw the fasting benefits of autophagy, the recycling of old cells.
  • I used an intermittent fasting app to track my fasting time accurately and measured my ketone levels in the afternoon before breaking my fast using these Keto Strips. On the days I did clean fasting, I entered ketosis earlier in the day and was in deep ketosis, as shown by the deep purple color on the Keto Strips. If I entered ketosis on the dirty fasting days, it was always in the trace to small ketone amounts. This showed me that clean fasting put me in fat-burning mode faster and at a deeper level than dirty fasting.

Now let’s take a closer look at how fasting can help you.

Benefits Of Intermittent Fasting

Here are some of the impressive benefits of fasting.

  • Improves weight loss
  • Increases belly fat loss
  • Regulates hormones
  • Repairs cells through a process called autophagy
  • Lowers your risk of type 2 diabetes
  • Increases longevity
  • Reduces LDL cholesterol and triglycerides
  • May help prevent cancer
  • May help prevent neurodegenerative diseases, including Alzheimer’s and Parkinson’s

If you’d like to learn more about the benefits of fasting, check out 9 Health Benefits Of Intermittent Fasting.

The 5 Stages Of Fasting

According to lifeapps.io, the creators of the LIFE Fasting Tracker app, there are five main stages, or phases, of intermittent and prolonged fasting:

  • Ketosis and heavy ketosis – This happens after 12 hours when your body starts breaking down body fat.
  • Autophagy – By 24 hours, your body is recycling old, worn-out cells like nobody’s business! Out with the old junk and in with new (rejuvenated) cells and tissues. Renewing your body is what autophagy does best.
  • Growth hormone – After 48 hours, your growth hormone level has risen by five times.
  • Insulin decrease – At 54 hours, your body is becoming more insulin-resistant.
  • Immune cell rejuvenation – By 72 hours, your body is busy breaking down old immune cells and building up new ones.
clean fasting / woman running outdoors
Clean vs. Dirty Fasting Pin this image to come back later.

Summary – Clean Fasting Vs. Dirty Fasting

I hope you enjoyed reading about my experiment with clean and dirty fasting. Hopefully, this information will help you on your fasting journey, especially if you want to lose weight and feel better.

Knowing the difference between clean and dirty fasting foods and drinks is crucial to gain optimal results from your fasting efforts. With this knowledge, you can achieve your health and weight loss goals.

The intermittent fasting lifestyle has given me so much freedom in life. One of the things I love most is that my focus is no longer on restricting certain foods but on living a healthier life and feeding my body what it needs in my feeding window.

I spent hours a day thinking about food, craving sweets and carbs, and eating to prevent another hypoglycemic episode. It was as though my life revolved around food…out of necessity.

But no more – thanks to fasting!

(Here are 50 things to do instead of eating when you’re intermittent fasting.)

Thankfully, now that I’ve discovered fasting, I’m not a slave to my next meal (or the scale). My body is healing and healthier, and I’m grateful for this natural practice that I plan to continue for the rest of my life.

For More Intermittent Fasting Articles, You’re Gonna Love:

What are your thoughts about clean and dirty fasting? Any questions about fasting?

8 thoughts on “What Is Clean Fasting And How It’ll Boost Your Fasting Results”

    1. Great question, and yes, absolutely! Just make sure you listen to your body. If you feel lightheaded or unwell, you may want to eat a healthy snack. I don’t suggest doing a super intense workout while you’re fasting, but a light to moderate one should be fine once your body adjusts to the practice.

    1. Hi Elena! This is a great question! The short answer is that people respond differently to coffee and caffeine. The caffeine in black coffee can increase blood sugar and insulin levels in people who have type 2 diabetes. For example, one study was done on a group of people with type 2 diabetes. It showed that as soon as they drank coffee their blood sugar shot up. Also, it was higher on their coffee-drinking days than on the days when they weren’t drinking coffee.

      But, (for people who don’t already have it) drinking black coffee daily has been shown to lower your risk of developing type 2 diabetes.

      Here are a couple of articles for more information: How Does Caffeine Affect Your Blood Sugar? and Coffee’s Effect On Diabetes I hope this helps!

    1. This is a great question, Elena! It depends on what you read…I’ve searched for a definitive answer to this in the research and haven’t had much luck. Many fasting “experts” recommend drinking lemon water, and I used to every morning. It’s been shown to lower insulin in people with diabetes so conventional wisdom would say it’s okay. But there is another camp of fasters who believe clean fasting includes only water, black coffee and unsweetened herbal and green teas. This is where I tend to fall now, but then again this one is fuzzy for me. You can always try it both ways and see how your body responds.

  1. I am going to try the 16:8 fasting…I also am hypoglycemic…my problem is I work a very odd continental shift…10hr days and 14hr nights so it is very hard to keep any kind of schedule…how often do you suggest I fast..does it have to be on a regular basis…

    1. I think 16:8 is a great place to start! So sorry you’re dealing with hypoglycemia but hoping the fasting will help you. I wouldn’t worry too much about not being able to keep a regular schedule with the fasting. Every little bit helps and will provide you with the benefits of fasting. (I always recommend talking to your doctor about your specific health needs and fasting plan.)

      The wonderful thing about fasting is that you can manipulate it to fit your schedule – no matter how irregular it may be. The important thing is to keep your fasting window. Once your body adjusts, that is. I’m not an advocate for pushing too hard in the beginning but believe in gently moving your body towards the new fasting schedule – especially when you’re dealing with hypoglycemia.

      There are so many different ways you can adjust your fasting: feasting schedule. 16:8, 18:6, 20:4, 23:1, and alternate-day fasting are some of the more popular schedules but the beauty of it is that YOU can choose any timing schedule that fits YOUR lifestyle and health needs. And as your hypoglycemia improves you may choose to lengthen the time you’re fasting (what I’ve done), or you may love it and stay there forever. Whatever you decide is up to you! This is one of the many things that I love about the freedom gained from fasting.

      Here are a couple of posts you may want to read (if you haven’t already) that will give you a clearer understanding of beginning your fasting journey. https://lorigeurin.com/how-intermittent-fasting-cured-my-hypoglycemia/ https://lorigeurin.com/quick-guide-to-intermittent-fasting/

      Please email me at healthylife@LoriGeurin.com with any questions. And I’d love it if you’re able to share an update or 2 with me on how it’s going. I’m excited for you, Dianne!

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.