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Can You Have This While Fasting?
5 Foods and 5 Drinks That Won’t Break Your Fast!

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Quick Summary tl;dr

Fasting isn’t just about skipping meals—it’s about making smart choices that keep you on track without breaking your fast. Whether you’re fasting for weight loss, metabolic health, or deeper benefits like autophagy, what you eat and drink during a fast depends on your goals.

When it comes to drinks, water, black coffee, and tea are your safest options. They’ll keep you hydrated and energized without affecting your fast. Bone broth and apple cider vinegar can be useful, especially during longer fasts, but keep in mind they contain minimal calories.

Some fasting protocols allow for small amounts of fats like MCT oil, coconut oil, or even bone broth. These can provide a boost during extended fasts without disrupting your goals. Supplements like electrolytes are essential for staying hydrated, especially during longer fasts, and sugar-free options like zero-carb gummies can help satisfy cravings.

In the end, fasting can be flexible, but it’s key to the right fasting approach what works best for your body and your goals.

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Table of Contents

Are you trying out fasting or considering it? If you've ever wondered exactly what you can eat and drink without breaking your fast, you're in the right place. Fasting isn't just about skipping meals—it's about smart choices that help you stay on track.

In this guide, we'll break down the drinks and snacks that fit perfectly within your fasting window, keeping you on track without breaking your fast. Plus, if you're curious about how adding keto can boost your fasting efforts, check out our detailed guide here.

What is Technically a Fast?

At first glance, fasting sounds simple—just stop eating, right? But there's more to it if you want to make sure you're getting the most out of it without accidentally breaking your fast.

Technically, a fast means sticking to very few or no calories. ( Longo et al, 2014) That said, you can still enjoy certain drinks and even some supplements as long as they don't push your body out of the fasting state.

The key is knowing how your body responds to what you're consuming. For example, pure fats like MCT oil or butter may not spike your insulin, so they’re often considered okay for some fasting methods. Still, some people argue that any calories technically break the fast.

It all comes down to your fasting goals—whether you're focused on weight loss, boosting metabolism, or getting deeper health benefits.

Your Fast, Your Goals

The types of foods and drinks you can consume during a fast really depend on your goals. Let’s break it down:

  • Weight Loss: If losing weight is your focus, keeping insulin levels low is key. ( Hall et al, 2017) You might wonder, “Can I have anything at all?” Sticking to zero-calorie drinks like water, black coffee, and tea will keep your insulin in check and help your body stay in fat-burning mode.
  • Improved Metabolism: Maybe you’re looking to give your metabolism a boost. In that case, adding a bit of MCT oil to your coffee could help. ( St-Onge et al, 2010) It won’t raise your insulin, and it can provide an energy boost, making your fast easier to manage.
  • Autophagy and Health Benefits: If your goal is deeper health benefits like autophagy (your body’s way of cleaning out damaged cells), then keeping it strict is important. ( Levine et al, 2008) Stick to water and herbal teas to keep this process going strong.

As you can see, what you choose to consume during your fast depends on what you’re hoping to achieve.

What Can You Drink During a Fast?

Now that you know how to align your fasting goals, you might be asking, “What can I drink while fasting?” Here’s what works without breaking your fast.

1. Water

Water is your best friend during a fast. Whether it’s still or sparkling, feel free to add a squeeze of lemon or lime for a bit of flavor without adding calories.

2. Black Coffee

Need a caffeine fix? Black coffee is a popular choice and won’t break your fast. ( Heckman et al, 2010) Just skip the sugar and cream to keep things in check.

3. Tea

Green, black, or herbal tea works well too. It’s a great way to stay hydrated and keep things interesting. Just remember, no sweeteners.

4. Bone Broth

Bone broth is a bit of a gray area. While it does contain some calories, it’s packed with electrolytes (super important during a fast!) and can be a good option for longer fasts when you need a little extra support. It’s a good option if you’re fasting for more than a day and need to replenish minerals and stay hydrated. Plus you can easily make bone broth at home!

5. Apple Cider Vinegar

Diluting a couple of tablespoons of apple cider vinegar in water can help can help curb hunger and stabilize blood sugar levels, especially during extended fasts.

Each of these options will help you stay hydrated and energized, without breaking your fast.

Can You Have This While Fasting? 5 Foods and 5 Drinks That Won’t Break Your Fast! Can You Have This While Fasting? 5 Foods and 5 Drinks That Won’t Break Your Fast! Can You Have This While Fasting? 5 Foods and 5 Drinks That Won’t Break Your Fast!

What Foods and Supplements Can You Have During a Fast?

While traditional fasting means no food, some fasting styles allow for a little wiggle room when it comes to certain foods and supplements. Here's what you might consider.

1. Fats

A bit controversial, but some people include small amounts of fats like coconut oil, MCT oil, or grass-fed butter in their coffee or tea (often called "Bulletproof coffee"). These fats can provide energy without spiking insulin levels, making them helpful during longer fasts. ( Heidt et al, 2023)

2. Gum and Mints

If you need to freshen your breath or curb your appetite a bit, sugar-free gum or mints are generally safe. Just make sure they don’t contain any hidden sugars or carbs that could affect your insulin.

3. Supplements

Most calorie-free supplements, like multivitamins, are fine to take during a fast. However, fat-soluble vitamins (like vitamins A, D, E, and K) are best taken with food, so it’s better to save those for your eating window.

4. Electrolytes

Electrolytes like sodium, potassium, and magnesium are especially important during longer fasts. You can find electrolyte supplements without sweeteners, or make your own Electrolyte Drink using a small amount of lime or lemon juice. To beat the summer heat you can even make a Slurpee out of it!

Get 15% off Perfect Keto Electrolytes and their fasting bundles. You can either use this link or apply code KDA at checkout.

5. Zero-Carb Gummies

You, this is true, you can even have gummies! For a little something sweet that won’t break your fast, zero-carb gummies are a great option. They’re made with zero-calorie sweeteners, tea or water and the optional sugar-free flavorings. They can even include electrolytes to help you stay hydrated. Try making your own with these easy recipes for Zero-Carb Gummies and Electrolyte Gummies.

Can You Have This While Fasting? 5 Foods and 5 Drinks That Won’t Break Your Fast! Can You Have This While Fasting? 5 Foods and 5 Drinks That Won’t Break Your Fast! Can You Have This While Fasting? 5 Foods and 5 Drinks That Won’t Break Your Fast!

Frequently Asked Questions About Fasting

Can I use sweeteners like allulose, stevia, xylitol, or erythritol without breaking my fast?

Yes, these sweeteners don’t contain calories and generally don’t impact your blood sugar. However, everyone’s different—some people may still experience cravings or slight insulin responses, so pay attention to how your body reacts.

Is it okay to drink diet soda while fasting?

While diet soda is calorie-free, it’s not always the best choice. Artificial sweeteners can sometimes trigger cravings and affect blood sugar levels for some people. If you’re aiming for a clean fast, it’s better to stick to water, black coffee, or tea.

Can taking supplements affect my fast?

Most supplements won’t break your fast, especially if they’re calorie-free. However, fat-soluble vitamins (like A, D, E, and K) are best taken with food, so it’s better to have those during your eating window for better absorption. If you do include a "bulletproof coffee", then it's good to take your fat-soluble vitamins with it.

What should I do if I feel very hungry or weak during a fast?

Mild hunger is normal, but if you feel weak or light-headed, it’s important to listen to your body. You can drink some water with electrolytes or have a small amount of bone broth to replenish minerals. If the symptoms persist, it might be a sign to break your fast.

How does drinking coffee or tea affect my fast?

Plain black coffee or tea is perfectly fine during fasting and can even help curb hunger. Just avoid adding sugar, milk, or cream to keep your fast intact. A small splash of unsweetened nut milk is usually okay if you need it.

Can I have bone broth during a fast, and how does it affect my fasting goals?

Bone broth contains a few calories but is often used during longer fasts because of its mineral content. It won’t keep you in a strict fast, but it’s a good option if you’re fasting for weight loss or looking to stay hydrated and nourished during an extended fast.

Conclusion

Fasting is more than just skipping meals—it's about making choices that help you stick to your goals. Whether you're fasting for weight loss, better metabolism, or deeper health benefits, the right drinks and snacks can help you stay on track without breaking your fast. Water, black coffee, tea, and even small amounts of fats like MCT oil can give you energy and keep your fast intact. Remember, the best approach is one that fits your body and goals, so feel free to adjust as needed.

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Martina Slajerova
Creator of KetoDietApp.com

Martina Slajerova

I changed the way I ate in 2011, when I was diagnosed with Hashimoto’s, an autoimmune disease that affects the thyroid. I had no energy, and I found it more and more difficult to maintain a healthy weight.

That’s when I decided to quit sugar, grains, and processed foods, and to start following a whole-foods-based ketogenic approach to food.

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Comments (6)

Thank you for this! I'm on day 3 of my extended fast which will end in a few hours. Only electrolytes and water. So far so good!
I know this will be a bit unrelated but could you possibly write an update on the erythritol study? It just seems that many bloggers are overwhelmingly against the study while doctors that I follow on Twitter seem to have a different opinion. I want to know what your thoughts are this time?

Thank you Carol, I'll make sure to put something together within the next week or so. I't been busy times with our now toddler twins but I will make sure to share my thoughts!

This is so interesting, I thought it was more about our goals but wasn't sure. I used to drink BPC when I started keto because back then it was kind of that trend and everyone was doing that. I'm one of those who don't believe that drinking BPC is fasting anymore 😊 Now I do a water-only fast and find it way better. It takes time to get used to it so I'd definitely not recommend this to anyone who just started keto. Give it a month and then fast. I do enjoy your electrolyte drink with lemon juice every day but that's almost zero calories and that's fine.

That is actually quite similar to what I do. I may have some coffee or tea but otherwise nothing else. I take my electrolytes in the morning unless it's just magnesium on that day which I always take before bed.

Thanks for this, I'm just about to start my next 3 day fast. Love the fact I can now track it in the app without having to do it separately. I didn't think of gummy bears made from fruit tea. What a great idea!

Thank you for your kind words! Good luck on the next fast!