Dirty Fasting vs. Clean Fasting For Weight Loss (What Will Break A Fast)

If you’ve tried intermittent fasting for any length of time, you’ve probably wondered one very important question.

“What can I drink while intermittent fasting”?

Some sources say anything with fewer than 25 calories or so (though zero is ideal) is fair game.

Others say you must be stricter than that – keeping it to a few select beverages other than water.

With so much conflicting information between scientific studies and personal anecdotes, how do you discover the truth?

How do you know what beverages you can drink while intermittent fasting?

In this post, I’ll answer that question in three parts.

First, we’ll discuss different schools of thought on either side of the argument.

Then, I’ll share a few thoughts based on my own results.

Finally, I’ll help you decide what might be the best approach for your unique situation and personal goals.


what will break your fasting window

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What Is Intermittent Fasting?

Just in case you don’t yet know, intermittent fasting has grown in popularity in recent years as a quick, easy way to lose weight.

Rather than restricting what you eat via strict dieting, with intermittent fasting, you get to eat a full meal once or twice a day, to satiety, including foods you truly enjoy (yes, even ice cream)!

All you do is select a “fasting window”, during which time you consume no calories, and a “feasting window”, during which time you eat all your food for the day.

While there is a variety of intermittent fasting schedules to choose from, the most popular is 16:8 intermittent fasting.

On such a plan, you’d fast for 16 hours each day and feast for 8 hours.

Most people on the 16:8 fasting diet plan stop eating after dinner around 8 pm, sleep through the night, skip breakfast the next day, then eat lunch around noon the following day.

Sounds doable, right?

Not so fast.

While it’s pretty obvious that you can eat nothing while fasting, what about drinking?


What Can I Drink While 16:8 Fasting?

what can i drink intermittent fasting weight loss

Here’s where the dirty fasting debate begins.

Keeping it super-simple, while intermittent fasting you should drink calorie-free, flavorless beverages.

This includes unflavored water, unsweetened tea, and coffee. That’s it.

If you follow these guidelines, you are “clean fasting”.

But if your goal of intermittent fasting is calorie restriction and weight loss, can you have zero-calorie artificial sweeteners? Or a splash of milk or creamer in your coffee, for taste?

This would be “dirty fasting”, and opinions on whether or not that will break your fast are mixed.


Clean Fasting vs. Dirty Fasting – What’s The Big Deal?

Before we go any further with the debate between clean and dirty fasting for weight loss, we much acknowledge a very important fact:

>>Calorie restriction isn’t the only way intermittent fasting helps with weight loss<<


How Does Intermittent Fasting Help With Weight Loss?

It’s obvious that consuming fewer calories is likely to help you lose weight.

And, it’s a lot easier to restrict calorie consumption if you’re only eating for 8 hours of the day instead of around the clock, right?

I mean, while it’s still possible to overeat in fewer hours, it is far less likely.

But there is another way intermittent fasting helps to lose weight – by eliminating anything that may create an insulin response.


Insulin Response And Weight Gain

Many people believe that zero-calorie artificial sweeteners are okay for fasting and weight loss because technically zero calories is still fasting.

But studies have shown that even the taste of something sweet – whether it has calories or not – is enough to make your body think you are having sugar.

In preparation for breaking down the incoming “sugar”, the body releases insulin, which helps your cells absorb glucose (sugar).

But when the body actually has no sugar for the insulin to work with, two adverse effects arise.

First, your blood sugar drops, thus increasing hunger and cravings – making it harder for you to continue your fast.

And second, insulin sends a signal to your body to stop using fat for energy, and to use glucose instead.

So, while the actual calories in artificial sweeteners may be zero and you technically aren’t breaking your fast – some of these sweeteners may be blocking you from achieving the results you desire.


What Really Matters To You?

That said, you have to think about your goals and what matters to YOU.

Some people just want to lose weight and don’t care if they’re technically breaking a fast or not, as long as the pounds come off.

Others want to do everything by the book and will be very particular about all the details, regardless of if it impacts their weight loss or not.

There’s nothing wrong with either approach, mind you.

But I want to take some time to go through individual items so you can make an informed choice for yourself based on your personal goals.


Does Black Coffee Break A Fast?

I’ve received this question so many times over the past few months. So, I wanted to say flat-out and definitively.

Will black coffee break your fast? Absolutely not!

In fact, it’s one of my go-to ways to stave off hunger cravings when I feel like I can’t make it all the way through my fasting window.

Drinking black coffee will NOT break your fast. So, have at it!


Does Artificial Sweetener Break A Fast?

is artificial sweetener okay intermittent fasting

Next, you might be wondering does Splenda break a fast? How about other artificial sweeteners? Does Stevia break a fast? Does erythritol break a fast?

The thing is, not all artificial sweeteners are created equal.

Research on artificial sweeteners and insulin response isn’t as robust as we’d like at this point, but a few studies have yielded interesting results:


-Powdered sucralose (like Splenda) does spike insulin, but liquid sucralose may not

-Erythritol-based sweeteners (such as Swerve) may not spike insulin

Stevia may also not spike insulin


Given this information, you might want to swap your Splenda for liquid sucralose just to be on the safe side (I certainly have and LOVE it!)

Furthermore, artificial sweeteners are not the only way some people prefer dirty fasting.

What about adding a little creamer to your coffee?

RELATED: 17 Food Swaps That’ll Help You Lose Weight


Does Coffee with Creamer Break A Fast?

can i put creamer in my coffee on intermittent fasting

This is where things seem a little backward.

Where there are zero calories in artificial sweeteners, (thus making them technically fasting-friendly), many will negate the benefits of your fast. Whereas creamer does contain calories and technically means you’re no longer fasting.

But a little creamer (say a tablespoon or so) doesn’t spike insulin and doesn’t really have adverse effects on weight loss.

Even Dr. Jason Fung, the author of the top fasting books, The Obesity Code and The Complete Guide to Fasting, says he uses cream in his coffee and it doesn’t stop him from reaching his goals.


Does Apple Cider Vinegar Break A Fast?

can i use apple cider vinegar intermittent fasting dirty

Next, you may have heard about the little trick of putting a little apple cider vinegar in your water in the morning or before meals to help with weight loss and digestion.

But will ACV break a fast?

While, again, “clean fasting” is ideally only water, unsweetened tea and black coffee, ACV has no calories and it’s likely that a teaspoon or so in a glass of water will not break your fast.


Can I Drink Flavored Sparkling Water While Intermittent Fasting?

Now I don’t know about you, but I love the cool, crisp taste of sparkling water!

It’s got the bubbly fizz of soda without the extra calories.

So you may be wondering if flavored sparkling water will break your fast.

Flavored sparkling water will definitely be considered “dirty” fasting, but it may not technically break your fast, provided it has zero calories whatsoever.

You should beware of the flavored sparkling waters that have any sugar or artificial fruit flavoring in them.

I’ve been shocked to find a can of unsweetened peach sparkling water still had calories in it.

A safer bet would be to get your own plain, zero-calorie sparkling water and add fruit to it to freshen it up a bit.

Sure, you might get a few trace calories from the fruit, but this is a far better option than the alternative.

Plus, it’s hydrating and will not prevent you from losing weight.


Clean Fasting vs. Dirty Fasting – What Counts?

This isn’t an exhaustive list by any means but is meant to help you wrap your mind around what qualifies as clean fasting and dirty fasting.

For the most part, anything other than water, unsweetened tea, or black coffee is dirty fasting. And it’s questionable as to which items labeled “dirty fasting” will actually break your fast.

Then, going a step deeper, even if something does break your fast, that does not mean it will keep you from losing weight.

BUT…  as a quick and dirty rule (no pun intended), here’s what you can use.


clean vs dirty fasting


How I Approach Clean vs. Dirty Fasting

Briefly, I’ll share my personal thoughts and approach to dirty fasting.

When I first tried intermittent fasting back in May 2018, I had no clue what clean or dirty fasting was.

Honestly, I don’t even think it was a thing back then, really. It seems to be a new-ish concept.

Anyway, I have a huge love of carbonated, zero-calorie energy drinks.

And while I can tolerate my coffee black, it’s not my preference.

That said, when I first tried intermittent fasting, I drank black coffee some of the time, while other times would drink a sugar-free energy drink, and I still lost ten pounds my first month 16:8 intermittent fasting.

The second time I tried fasting just 12 hours a day and lost even more weight with a cleaner diet, but I still dirty fasted (again, without knowing what dirty fasting was).

I’ve been fasting consistently for a while now and it has become a natural lifestyle for me.

I will say that I no longer clean fast at all and am maintaining a weight loss of over 50 pounds, still losing 1-2 pounds per week while drinking energy drinks and some diet soda during my fasting window.

So, dirty fasting works for me and I’ll continue with it.

BUT… I also believe in considering new and useful information when I discover it.

As such, I feel two ways about this.


Two Viewpoints On Dirty Fasting

If you’re losing weight while dirty fasting, should you aim for even better results by moving to clean fasting?

Or… if you’re overweight or obese because you have a hard time sticking to complicated, over-limiting diets that suck all the joy out of your life – and wind up relapsing or quitting altogether – are you better off with a moderate plan that you can actually live with?


Should You Clean Or Dirty Fast?

clean fasting vs dirty fasting

So, now that you know what clean and dirty fasting are all about, how can you tell which option you should go with?

I believe the answer lies in a combination of factors.

First, you should consider what you’ve already tried and how you feel about it.

-If you’ve been dirty fasting and aren’t losing weight? Maybe you should try to clean up your fast and see if that helps.

-If you’ve been dirty fasting and it’s working well for you – it fits your lifestyle and you feel comfortable enough to where you can stick with this for the long-haul? Maybe you’re fine with keeping it at dirty fasting.

-If you’re clean fasting and the weight is coming off, yet you’re totally miserable with such bland beverages. And you feel like you might not be able to commit to it long-term for this very reason? Maybe you can try adding a little creamer or sweetener in your coffee or tea, then check your weight over the next few weeks to see if it stalls you out any.

-If you’re clean fasting and the weight isn’t coming off? See what other reason you have for not losing weight on intermittent fasting. If it’s something like you’re not fasting long enough, and this could be because you just can’t hack black coffee and water, maybe adding a little creamer or flavor can get you over the hump to where you’re fasting long enough to make a difference.

-If you’re brand new to intermittent fasting and want to know how best to start out? Try clean! Try doing it absolutely perfectly and see how it feels! You may find it to be not so bad, and it’s a great idea to give yourself the highest chance of success at the outset.

I’d have started with clean fasting had I really known much about it at the time, honestly.

It just so happens I had success the other way and rolled with that.


Don’t Listen To The Naysayers

Another thing I’d like to add…

It seems like with weight loss people get really passionate and almost cult-like about their beliefs and choices.

During my stint with the ketogenic diet, I saw this play out full-force in various forums and subreddits.

And oh, boy!

People go on full out flame wars behind what you should do and what’s best and what’s right or wrong.

At the end of the day? None of it matters!

The only thing that matters is that you’re taking active steps to improve your life and reach your goals.

That you’re willing to pay attention to what your body is telling you, and make tweaks and improvements where need-be.

And that YOU are happy with YOUR dietary choices!


Different Strokes For Different Folks

Some people thrive on dirty fasting, while others can’t lose a pound.

Some people feel like black coffee is tolerable and find it easy breezy, while others really hate it and would fall off altogether if they were forced into it.

So what if it’s not “right”?

So what if it “breaks your fast”.

If you’re losing the weight you desire, and you feel good about yourself and your progress, that’s all that really matters.

You are your own best teacher. The sooner you realize that, the better off you’ll be!


Does It Matter What You Drink While Eating?

As a final note, I wanted to talk a little bit about if it matters what you drink while eating?

The beauty of intermittent fasting is that it’s a restriction on when you eat, not what you eat. So, technically, you can drink whatever you want during your mealtimes.

BUT… if your main goal of intermittent fasting is to lose weight, it serves you best to avoid drinking your calories.

So, it’s not breaking intermittent fasting rules to drink calories while eating. Just beware of blowing your caloric budget for the day on liquids — these are better spent on wholesome, tasty foods!


Oh and by the way…

fasting 12 hours before after

If you’d like to get started with intermittent fasting or you want to take your intermittent fasting weight loss to the next level, what you really need is my Intermittent Fasting Weight Loss Planner! 

It literally has everything you need to track fasting, strength & cardio training, pounds/inches lost, space for notes, slots for before & after pics, and three 30-day fitness challenge charts! 


Happy fasting! 🙂

Alex from Eat Those Plants
Alex from Eat Those Plants

My name is Alex and I'm a passionate advocate of a whole food plant-based lifestyle. Since losing over 40 pounds on a vegan diet I've created the Eat Those Plants website to help you look good and feel great by putting more plants on your plate!