Diet Soda and Fasting: Great or Bad Idea?

drink soda

Your Imam, guru, or personal coach has probably let you understand you should avoid the plate during your intermittent fast. But thank heavens, you are allowed to drink something! And if our guess is correct, you’ve probably had a diet soda recommended for your in-fasting hydration needs. But is diet soda really a great idea for a beverage while fasting? What are its benefits, if it has any, and what are its downsides? Are there healthier alternatives? 

Many questions, for sure. But don’t worry. Let’s answer them right away, beginning with addressing the large horse in the room.

What Is Diet Soda and What Does It Contain?

Diet soda is simply a blend of sweeteners (artificial or natural), carbonated water, flavors, colors, and some food additives. 

The thing about diet sodas is that they just don’t contain that much. At least, not much that’s of nutritional value to you. Diet sodas are not very rich in calories, typically containing a paltry amount for any nutritional value. For instance, a 354 mL can of Diet Coke has 40 mg of salt but no calories, sugar, fat, or protein. 

However, it is worth noting that some diet sodas may contain way more nutritional value than others. 

Is Diet Soda Good to Drink While Fasting?

Having seen what you can expect to find in a bottle of diet soda, let’s now ask: can you drink diet soda while fasting? 

Well, on the surface, it would seem that way. Aside from the cool, refreshing, and carbonated feeling from drinking this stuff, it also has zero sugar and won’t leave you with excess calories to burn off. No, seriously. Diet soda is not too bad an idea in and of itself, and how advisable it is for you depends, to a degree, on why you’re fasting and whether you have any underlying health weak spots it can affect.

shakes drink

However, as science studies the matter a bit more, it has become apparent that there’s no real benefit to chugging diet sodas, especially not if you are fasting. On the contrary, studies have found a number of potential health risks associated with the beverage.

Health Risks of Drinking Diet Soda

These are some of the health risks that diet soda exposes you to. 


If you find it ironic that something marketed as being ‘diet’ might actually increase your odds of being obese, that’s because it is. However, this has less to do with the soda itself and more to do with the sweeteners used. Although, it is worth pointing out that this still needs to be conclusive.

In any case, the idea is that there are some people with special conditions;0 and consumption of these sweeteners among such people can be linked with an increase in Insulin resistance and obesity. People in this boat include sufferers of Type-2 Diabetes and Prediabetes or people already predisposed to be obese. 

Sleeping Problems 

One thing that diet sodas tend to contain, aside from sweeteners and flavors, is caffeine. And we all know how sleep-friendly caffeine is.

On average, your favorite diet soda will not necessarily contain as much caffeine as, say, your morning coffee. It may generally even contain less than normal, non-diet soda. However, everyone processes caffeine at a different rate, and the amount in your diet soda might still be enough to turn your night into a waking day. So, if you plan to sleep any fewer than five to eight hours during or after your fast or don’t want to screw up your sleep cycle, you should probably avoid soda while fasting. 

Mental Health

Did you know that diet cola may also have an effect on your mental health? According to some studies, people who drank four or more diet or normal sodas per day have been found to have an increased incidence of depression. However, it is unclear whether diet soda or any of its contents, in particular, is the cause.

Organ Health

Diet cola is associated with low calories, low nutrients, and now also an increased risk of a whole range of organ diseases.

Take, for instance, your kidneys. Studies have found a correlation between diet cola consumption and the risk of chronic kidney disease. One such study of about 15,368 people and their diets found that those who had more than seven glasses of diet soda per week had nearly twice as much risk of chronic kidney disease as those who had only one per week. And speaking of kidney diseases, diabetes (which happens to be the leading cause of kidney disease) is also known to be 21% more likely in diet soda drinkers. 

Then, consider the heart; multiple studies have also linked diet soda consumption to increased risk of cardiac and other related diseases like hypertension. For example, one study based only on observational data connected diet soda to a slight increase in the risk of stroke. Additionally, a metastudy of four studies involving 227,254 participants found a 9% higher risk of high blood pressure for each serving of an artificially sweetened beverage that you consume daily. 

As far as the data indicates, diet soda is not too great for organ health. And seeing everything it’s not good for, what then would be better?

What Do I Drink, Then?

Luckily, there are several great alternatives to Diet soda for your fasting beverage needs. For instance, you can substitute black coffee or sugar-free green tea for Diet soda. You may also want to try some refreshing herbal teas; they have antioxidant properties and improve digestion and boost immunity. 

But maybe coffee and/or tea aren’t your thing. Maybe you prefer carbonated beverages instead. In that case, consider unflavored, unsweetened seltzer water. You will find that it has no calories and no artificial sweeteners. You can add a little lemon, cucumber, or mint to improve the flavor. You could also just drink water. Really. Water is the master-hydrator, and it will neither raise your insulin levels nor make you likely to get some kind of cancer. 

Closing Thoughts

Intermittent fasting is a great exercise to undertake, especially if you do it right. And doing it right involves minding your nutritional needs and ensuring you don’t harm your health. Diet soda is nominally a great way to stay hydrated during your fast, but as we have seen, it has very few benefits and many risks. Our candid advice? Instead of diet soda, try any of the healthier alternatives. Or, at the very least, if you really want soda, take it in very sparring quantities.