Does Splenda Break a Fast? It Depends on This

If you’ve wondered if adding a little Splenda to sweeten up your morning coffee will break your intermittent fasting, then you’re not alone.

Intermittent fasting is becoming quite popular for its health, weight loss, and anti-aging benefits. But understanding what you can and can’t have during fasting is crucial for results. Splenda, a common sugar substitute, is often in the heat of discussion.

But this zero-calorie sweetener can break your fasting period. There’s nothing worse than undoing all your hard work and discipline with your intermittent fasting regimen.

In this post, you’ll discover the answer once and for all; the short answer is it’s complicated. Here, we’ll dive into the science behind Splenda and its effects on fasting. You’ll have clarity and be able to make informed decisions on using this artificial sweetener during your intermittent fasting period.

Will Splenda Break a Fast

boxes of splenda packets at costco

So, does Splenda break a fast?

The short answer is that Splenda and other zero-calorie artificial sweeteners won’t break you fast if your main goal is weight loss. Many who use Splenda will still get results with weight loss but may have lesser results from fasting, such as autophagy and improved gut health.

It comes down to what you are using intermittent fasting for. If your main goal is to lose weight, adding a little packet of Splenda to your morning coffee won’t break you fast, and you can still get results. But it’s best to fast as cleanly as possible to maximize all aspects of intermittent fasting, such as autophagy, gut health, and mental clarity.

Dirty intermittent fasting is a less strict fasting method that allows certain ingredients and beverages. Adding these during your fasting window can curb hunger, making the fast more tolerable to get through. But purists believe you should strictly only have water during your fasting window to maximize results.

Intermittent fasting can be pretty difficult if you’re not used to it. You can get starving and lightheaded during your fasting period if you’re used to eating throughout the day. Adding some select ingredients and beverages during your fasting window can make it easier to keep fasting.

The longer you can keep fasting, the better the results you will get. If fasting is too unbearable, then it’s too tempting to give up. If your main goal is weight loss, then it’s best to have a little leeway and allow Splenda during your fasting period to keep fasting longer.

This includes adding Splenda to your morning coffee. A “50-calorie rule” with dirty fasting allows a small amount of calorie intake without breaking your fast.

Key Takeaways:

  • If your main goal with intermittent fasting is weight loss, then Splenda will not break your fast.
  • With fasting for weight loss, you can have things other than water to help make the fast more tolerable.
  • If adding Splenda to your fasting routine helps you keep fasting for longer, then you’ll win in the long run.

What Is Splenda Made Of (Pick the Right One)

box of splenda sweetener on grocery store shelf

Splenda is an artificial sweetener that is sucralose mixed with dextrose (a sugar) and maltodextrin (a carb). While sucralose itself is zero-calorie, the same can’t be said of dextrose and maltodextrin. Sugar and carb consumption should be minimized to get the best results with fasting.

To minimize the impact of Splenda during your fasting window, it’s best to only use Splenda Zero. Splenda Zero won’t break a fast, especially since it won’t contain dextrose or maltodextrin, as you’ll find in the Splenda packets.

There are conflicting studies on whether or not sucralose stimulates insulin secretion, GLP-1, or GIP release in healthy humans.1,2 But with that said, many fasting purists believe if you consume anything sweet, then your body could have an insulin response.

So, can you take Splenda while fasting?

You can have Splenda during fasting, especially if your goal is weight loss. Studies have found sucralose can cause a blood sugar spike in new users, but regular users probably won’t have a similar response.3

But be careful with those Splenda packets when fasting since they could break your fast. This is why…

Downsides of Splenda With Fasting

splenda nutrition facts on back of box

The dextrose and maltodextrin in Splenda packets are a sugar and carb that will cause an increase in blood sugar levels and an insulin response. For this reason, you should really go with Splenda Zero instead during your fasting period.

But the tiny amount of both dextrose and maltodextrin in Splenda packets is so small that it probably wouldn’t make a huge difference. If you’re trying to keep all your ducks in a row with perfecting your fasting window, then stick to Splenda Zero instead. But if you’re following a more “dirty fasting” routine, then the regular Splenda packets will probably be fine.

There are some studies finding sucralose can damage your gut and brain health.4 The amount of healthy bacteria in your gut can worsen. A study found that Splenda had a negative impact on overall memory and judgment.5

If you are going to use Splenda, then it’s best to do so in low amounts. It’s technically ok to have it every day, but if you can skip it some days, go for it. Responses may vary differently based on the individual, so it’s best to see how you react to it personally.

I prefer stevia as a sugar substitute instead of sucralose during my intermittent fasting period. Stevia comes from a plant, is zero-calories, and doesn’t raise blood sugar levels or cause an insulin response.

Sucralose in Splenda is a chemical that’s 650 times sweeter than sugar.6 Stevia is from a natural plant that is 200-350 times sweeter than sugar.7 Since stevia is less sweet than Splenda, it may be a better sugar substitute during your intermittent fasting period.

Despite being zero calories, there is a belief that Splenda and other artificial sweeteners could still cause weight gain in the long run.8 Since Splenda is so sweet, it could cause you to prefer sweeter foods. Since there are zero calories in sucralose, your body could crave food since it’s expecting incoming calories, too.9

Why You Should Add a Sweetener to Your Coffee While Fasting

Ultimately, it all comes down to adding a sugar substitute like Splenda during your fasting period, which will make it easier to get through your fast. Fasting purists believe you should strictly only have water during your fast, which also makes it much harder.

If you get too hungry and feel too deprived with intermittent fasting, then most people give up on it. But if adding a little Splenda to your morning coffee makes you happy so you can keep fasting for longer, then go for it.

For many, having Splenda in their morning coffee gives psychological satisfaction, making it easier to keep fasting longer. If you don’t like drinking black coffee, it’ll only make it much more challenging to get through your intermittent fasting period.

So, what else can you put in your coffee that won’t break your fast?

  • a splash of heavy cream or half-and-half
  • sucralose
  • aspartame (Equal)
  • stevia
  • allulose
  • monk fruit
  • sugar alcohols (xylitol, erythritol)
  • MCTs

Keep in mind there are studies linking the artificial sweetener aspartame to health issues like gut problems (gas, bloating, diarrhea), headaches, and migraines, affect mood and behavior, possibly increase cancer risk, and like sucralose can possibly cause an increase in appetite as well as weight gain.10

MCTs are my preferred ingredient to put in my morning coffee to boost the results from intermittent fasting. Your body quickly converts MCTs into ketones, a fuel source your body makes from fat stores.11 This helps kickstart the fat-burning process while giving you an energy boost, brain fuel, and curbing hunger.

C8-MCTs are the most efficient form of MCTs. One study found C8-MCTs to be 10x more ketogenic than other forms.12 I prefer to use them in a keto coffee creamer form, so I won’t have to use another creamer or sweetener.

My Pick
BioTrust Keto Elevate

Support Many of the Keto Benefits Associated With Increased Ketones, & Support Them FAST, but Without the Difficulty of Doing Keto...

Increase Ketone Levels Inside Your Body to Boost Metabolism, Elevate Energy & Enhance Mental Focus

  • 3X Better Than Coconut Oil, Butter or MCTs
  • Heightened energy levels
  • Reduced cravings & appetite
  • Graceful aging
  • Healthy metabolism
  • Increased mental clarity & focus
  • Heightened physical performance and recovery


So, does Splenda break a fast?

At the end of the day, if Splenda helps you get through a fast and if your main goal is weight loss, then having it is just fine. 16 hours is the magic fasting length for many, and getting through that long period can be challenging. So, if having some Splenda helps, then go for it.

You, of course, also have to be mindful of what else you’re eating during the day. Having a zero-calorie sweetener like Splenda and skipping meals while fasting can cause some to overcompensate and overeat later. This will stop you from losing weight, so it’s best to focus on what else you eat too.

While I prefer stevia over Splenda as a calorie-free sweetener, that doesn’t mean you can’t have it. Just make sure to use Splenda Zero instead since it doesn’t contain dextrose and maltodextrin, as you’ll find in the packets.

Keep fasting!