Can You Drink Diet Soda While Intermittent Fasting?

Page Medically Reviewed and Edited by Cyrus Khambatta, PhD

Can You Drink Diet Soda While Intermittent Fasting?

There are certain drinks you can have while you’re on your intermittent fast, but diet soda is not one of them.

One reason why you’re fasting, besides to boost your weight loss, is to give your body a break from chemicals, pesticides, and non-nutritive compounds that your body may be flooded with from the foods you eat and beverages you drink.

A fast gives your body the chance to cleanse, repair cells, reduce inflammation, lower your disease risk, and boosts weight loss.

That’s why drinking diet soda, while intermittent fasting has a very simple answer:

No. I’ll explain why in a moment, but first, let’s briefly go through what you CAN have while you’re fasting.

Intermittent Fasting APPROVED Drinks 

During the fasting stage, it’s important for you to skip any foods or drinks that may add extra calories.

You need to remember, anything that goes in your body over 50 calories, ends your fast.

But don’t worry, there are plenty of beverages you can drink that 1) contain ZERO calories, 2) may help accelerate the results of your fast, and 3) are approved drinks that do not break your fast.

Here’s a short list of approved drinks you can have on your fast:

Water—besides hydrating you, water gives you a feeling of fullness, which could shut down hunger and craving signals.

Tea—all types of tea are approved on your fast, but there is only one that could take your intermittent fast to the next level.  Amla Green Tea, a mix of rich Oolong Green Tea leaves morphed with Indian Gooseberries (Amla), may curb hunger while flushing your body with powerful antioxidants, at a time when your body is ready and hungry for the right nutrients.  Plus, the Amla fruit gives you a jolt of energy that last through the day.

Coffee—a cup best served in its natural state, coffee packs powerful antioxidants that could repair cellular damage caused by free radicals.  Skip the cream and sugar, as both may damper the antioxidant power and break your fast.

Apple Cider Vinegar—this tonic has been used for centuries for a number of health ailments.  It may stabilize your blood sugar, therefore shutting down hunger and cravings before they start.


As you can see, it’s important that everything you drink has very little, to no calories, so you can maintain your fast.

This brings us to diet soda—which also contains zero calories...  


Even though diet soda contains zero calories, it does contain harmful compounds that have detrimental effects to your health and body when you drink it.

The Argument Against Diet Soda

Everyone knows that sugar-sweetened beverages, like fruit juices or soda, may increase blood sugar, therefore raising the risk for weight gain or type 2 Diabetes.

What about diet soda — or the “non-calorie, non-sugar” soda?  Well, research shows that diet soda is just as bad as regular, sugar-sweetened beverages.

Although diet soda is marketed for weight loss and a drink for diabetics, it may increase blood sugar, which could increase your risk (or make) your diabetes worse.

But it’s not just diabetes that you need to worry about.  Studies may link the consumption of diet soda to weight gain and metabolic syndrome—both risk factors for diabetes.

Metabolic syndrome is a group of risk factors clumped together which could increase diabetes, heart disease, and stroke risk.

Metabolic syndrome is highlighted by:

  • Low HDL (or good) cholesterol levels
  • High blood sugar levels
  • Increased weight gain around the belly
  • High levels of triglycerides in the blood
  • High blood pressure

Alone, these risk factors may be easily treated.  But together, they may lead to complications with your health.

A study published in Diabetes Care shows a link between drinking diet soda and metabolic syndrome and diabetes risk.

The conclusion of the study showed that drinking diet soda, at least one can per day, was associated with a significantly greater risk for metabolic syndrome and diabetes risk.

Another study published in the American Journal of Clinical Nutrition showed a higher risk for diabetes from drinking diet soda.

They followed over 66,000 women for 14 years, and found some surprising results. Women who drank sugar-sweetened beverages showed an increased risk for diabetes.


Those who drank diet soda, or artificially-sweetened beverages, were just as likely to develop diabetes as those who drank sugar-sweetened beverages.

And there’s one more…

A study out of Purdue University showed that diet soda may increase your insulin production—which could lead to many different health issues, including high cholesterol, high blood sugar (from insulin resistance), and central obesity (more weight around the middle).

This is a recipe for metabolic syndrome and the beginning of diabetes.

Even though diet soda may increase your risk for diabetes, many people will still ask:

Can you drink diet pop while intermittent fasting?  

The answer is no.

The reason for this is pretty simple:

On a fast, you’re trying to give your body a chance to function normally, free from chemicals.

Even though diet soda has zero calories, it is artificially sweetened by chemicals that could destroy your body.

As you can see from the studies above, artificial sweeteners may wreak havoc on your blood sugar and insulin levels.

Plus, if you’re using diet soda as a pick-me-up during the day, there is a better option…and it’s not coffee.

The fruit found in Amla Green Tea provides natural energy and is considered a go-to caffeine substitute.  Just one cup provides enough natural energy to help you tackle the day—with plenty left in the tank.

Should You Drink Diet pop While Intermittent Fasting

As you know, during the fasting phase, you shouldn’t consume any calories—from food or from drinking.

This brings up the question: can I drink diet soda while intermittent fasting.  Even though it’s contains zero calories, it still contains artificial sweeteners and chemicals that could ruin your health.

Studies show that diet soda may be just as bad—or even worse—for your health compared to sugar-sweetened beverages.  Studies show that drinking diet soda may increase your insulin levels, leading to high cholesterol and increased weight gain around your waist—two things that defeat a fast.

Also, drinking diet soda may increases your blood sugar levels, leading to hunger, cravings, irritability, and weight gain.

The best advice: If you are just thirsty and want to fill your stomach, plain old water is a good bet. 

If you want to curb your hunger with added benefits like stabilizing blood sugar, getting a boost of energy and pumping up your antioxidants a fortified green tea like Amla Green is a great option.

Page Medically Reviewed and Edited by
Cyrus Khambatta, PhD

Cyrus Khambatta, PhD, is a cofounder of Mastering Diabetes and Amla Green is an internationally recognized nutrition and fitness coach who has been living with type 1 diabetes since 2002. Using an evidence-based approach to nutrition and fitness, he first reduced his own insulin usage by more than 40%, and has educated thousands of people with all forms of diabetes how to reverse insulin resistance using food as medicine. Cyrus earned a Bachelor of Science in Mechanical Engineering from Stanford University in 2003, then earned a PhD in Nutritional Biochemistry from the University of California at Berkeley in 2012. He is the co-host of the annual Mastering Diabetes Online Summit, a featured speaker at the Plant-Based Nutrition and Healthcare Conference (PBNHC), the American College of Lifestyle Medicine (ACLM) Conference, Plant Stock, and has been featured on Forks Over Knives, NPR, PBS, KQED, Fast Company, and is the author of the upcoming book Mastering Diabetes.

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