Can You Drink Diet Soda on the Keto Diet?

minute read | Last update: Nov 30th2022

This article is backed by studies and reviewed by a certified dietician.

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You’re one of those keto dieters who reduce calories as well as carbs, which is why you always avoid drinking regular soda. The past few days though, you’ve had a hankering for soft drinks. Are diet sodas a better option?

Although technically diet soda is low in calories, carbs, and sugar, it’s inadvisable to drink diet soda on keto. The low-cal sweeteners could lead to increased body fat, plus you’re at a higher risk of kidney disease, high blood pressure, and even heart disease.

Ahead, we’ll explain in full why diet soda on keto is not the best beverage choice and what other beverages to avoid. Make sure you keep reading, as you won’t want to miss it.

What Is Diet Soda? How Is It Different Than Regular Soda?

You see it on grocery store shelves and in vending machines almost as often as you do regular soda. We’re talking, of course, about diet soft drinks. Since they have “diet” right in the name, diet sodas certainly appeal to specific subsets of people, keto dieters among them.

You might see diet sodas marketed as low-calorie, no-calorie, or sugar-free, but they’re all referring to the same type of beverage. Diet sodas are supposed to taste like your favorite soft drink brand but without all the sugar and calories.

All the best-selling soda brands make diet versions, from Barq’s to Fresca, Sprite, Mountain Dew, Dr. Pepper, Pepsi, and Coke.

There are two primary differences between regular soda and diet soda. The first is the nutritional profile and the second is the source of sugar. Let’s talk more about these differences now.

Nutritional Content

Since Coca-Cola is one of the most popular soft drink brands, let’s assess the nutritional profile of regular Coke versus Diet Coke.

Here is the nutrition for a 21-fluid-ounce can of regular Coke:

  • 182 calories
  • 1 grams of total fat
  • 19 milligrams of sodium
  • 10 milligrams of potassium
  • 46 grams of carbs (15 percent of your recommended daily value)
  • 44 grams of sugar
  • 3 grams of protein
  • 39 milligrams of caffeine
  • 2 percent iron
  • 1 percent calcium

Now let’s take a closer look at the nutrition for a 12-fluid-ounce can of Diet Coke:

  • 0 calories
  • 0 grams of total fat
  • 40 milligrams of sodium (2 percent of your recommended daily value)
  • 0 grams of carbs
  • 0 grams of sugar
  • 0 grams of protein
  • 46 milligrams of caffeine

The choice is clear, especially for someone trying to lose weight or cut down on their sugar or carbs: Diet Coke is a “healthier” choice.

Sugar Sources

The other significant difference between regular and diet soda is what the beverages are sweetened with.

Sugar sources such as corn sweeteners and sucrose contain carbs, sugar, and calories. That’s why regular sodas are such sugar and carb bombs, not to mention that one can of soda contains almost 200 calories.

Diet soda uses artificial sweeteners that boast almost no calories and don’t ratchet up the carb content either. One such sweetener is aspartame. Compared to regular soda, there’s less sweetener used in diet soda.

The reason? Aspartame is way, way sweeter than even high-fructose corn syrup. Compared to sucrose, aspartame tastes up to 200 times sweeter, so a little goes a long way.

Is Diet Soda Good to Drink on the Keto Diet?

For you, it seems like diet soda checks all the right boxes. It’s low-cal, has no carbs, and contains no sugar either. You’re ready to crack open a can today to treat yourself after a long day at work or an especially strenuous workout at the gym.

Not so fast.

While it’s true that Diet Coke, Diet Barq’s, or Diet Sprite won’t increase your carb load for the day, diet drinks can wreak a lot of other havoc on your health. Here are some of the effects of drinking diet soda that make it not so keto-friendly.

Could Encourage Fat Storage

If you’ve ever tried the Paleo diet, then you’ll quickly notice that sugar is nowhere in your dietary allowance. That’s because the Paleo diet, aka the caveman diet, is supposed to help you eat like our ancestors did.

Sugar in the human diet came about very slowly, starting as only honey used as a sweetener. Today, sweeteners run the gamut, as we showed you in the last section.

Since sweet tastes were about as rare as could be for a long time, our bodies developed a specific reaction to sugary flavors. The ingestion of sugar told the body to begin storing fat to get through a long winter.

You have to remember, in the generations before modern society, there were no long-term heating methods like a furnace or a heater. Fat storage was integral for survival.

Our bodily reactions today haven’t quite caught up to modern times, so when you ingest a lot of sugar, to your body, that can still mean that you should hold onto fat for colder, more difficult times ahead.

A study published in 2015 in the journal Nutrients was one of many bodies of research that suggested a relationship between metabolic syndrome and obesity risk and drinking diet soda.

As a keto dieter, holding onto extra fat is especially problematic, as it flies in the face of the premise of your diet. You’re supposed to reduce your carb load so your body can begin burning fat instead of glucose.

When your body won’t let go of fat, you won’t see the results you were hoping for.

Might Lead to Kidney Disease

Kidney disease prevents your kidneys from filtering fluid and waste, allowing the waste to accumulate. Since the symptoms aren’t quick to manifest and can vary from case to case, kidney disease can easily become chronic.

Untreated or poorly treated chronic kidney disease can lead to kidney failure. If your kidney failure is acute, it can be fatal.

A 2017 study from the Clinical Journal of the American Society of Nephrology paints a harrowing picture of kidney health and diet soda consumption. The study involved 15,368 participants.

The participants who drank over seven glasses of diet soda every week had their chances of developing kidney disease double. This wasn’t just any kidney disease, but end-stage kidney disease, which is the most advanced stage of chronic kidney disease.

Your kidneys stop functioning if you have end-stage kidney disease, with your only treatment options being a kidney transplant or dialysis. End-stage kidney disease can kill you.

Diet soda on keto Can Aggravate Your Gut

In your body is a gut microbiome, which is where all the healthy microorganisms and gut flora live. A healthy gut microbiome is integral for wellbeing, which is why diet soda is so detrimental.

According to a 2019 edition of Advances in Nutrition, artificial sweeteners such as Stevia, sucralose, and saccharin can alter your gut microbiome, introducing unhealthy microbes that run off the healthier microorganisms.

Your immune system reacts, causing fat storage and even weight gain in association with the increase in diet soda consumption.

Diet soda on keto Might Lead to Cravings

If you start drinking diet soda on keto, you might find yourself craving more, and then even more. When you drink a can or two of diet soda, the cravings don’t go away. If anything, sometimes it seems like they get worse.

This is no coincidence. A Yale Journal of Biology and Medicine study from 2010 explains what happens. When drinking diet soda, your body expects that the sweet flavor will be delivered by glucose.

That release of glucose into your system produces a rush of dopamine, a feel-good hormone. Yet you’re not drinking regular soda, you’re having a can of diet soda on keto. Thus, there is no glucose coming.

Your body is confused, so it ramps up the cravings for sweet foods, thinking that if you comply, the glucose will be provided. You might try to put up with the cravings for as long as you can, but if you cave, you could take yourself out of ketosis and undo all the hard work you’ve put into your diet.

Could Contribute to Heart Disease

You’ve only got one heart, so you must take good care of it. That’s another reason to avoid diet soda on keto.

In 2016, the journal Archives of Cardiovascular Diseases published the results of several studies with 227,000+ participants. Across the research, the data says that for every beverage you drink per day that has artificial sweeteners, your blood pressure has a nine percent chance of elevating.

Some studies believe that consuming diet soda could lead to stroke. What’s far clearer is that unchecked high blood pressure can cause stroke, not to mention your risk of heart disease is higher.

Did you know that, in the United States, heart disease is the leading killer? So says the CDC in 2021 data. In the country, one death occurs every 36 seconds from heart disease. In a year, heart disease kills 659,000 people in the US.

If that’s not a reason to skip the diet soda, we don’t know what is!

What Other Beverages Aren’t Keto-Friendly?

Don’t be fooled. Although diet soda is known for containing artificial sweeteners, it’s far from the only beverage that does. When you come across a drink with strong sweetness but no carbs or calories, you can bet it uses aspartame, Stevia, or another artificial sweetener.

Fruit juice is one such example. Juice isn’t the best beverage choice for keto diets since it’s so carb-heavy. That’s true even of 100-percent fruit juice. If you’re craving juice, you’ll have to make your own.

Milk is another beverage that bogged down by too many carbs for keto dieters to ingest often. You can add a splash of milk to your morning cup of coffee, but milkshakes, chocolate milk, and other milk-based beverages are off the list.

The best beverage you can drink on keto is water. It’s calorie-free and has no carbs or sugar!


Diet soda on keto might seem like a dream at first. It contains the flavor and sweetness of soda but without the carbs, calories, and sugar. Very quickly though, you’ll realize that diet soda is a nightmare.

The artificial sweeteners in diet soda might cause you to pack on body fat. You could develop kidney disease, high blood pressure, and even heart disease in serious instances.

No soda is keto-friendly, so it’s worth it to begin scaling back your consumption.

About the author

The Authentic Keto Team is here to bring you health tips that help you with losing weight fast. We focus on a clean keto diet for beginners because we believe that is the easiest and most simple way to healthy eating. Our keto weight loss tips will not only bring you into ketosis fast but will also help you to improve your mental health, sleep problems, and wellness.

- Our goal is to make keto success easy. -

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