Diabetes: Does Diet Soda Raise Blood Sugar and Affect A1C Levels?

  • Medical Reviewer: Mahammad Juber, MD
Medically Reviewed on 2/8/2023

Blood sugar, insulin, and A1C

Diet soda is popular for people with diabetes. Diet soda doesn't directly impact your blood sugar or A1C levels, but people who are overweight and have a lot of blood sugar may have a sugar response to artificial sweeteners, which in turn causes a rise in blood sugar.
Diet soda is popular for people with diabetes. Diet soda doesn't directly impact your blood sugar or A1C levels, but people who are overweight and have a lot of blood sugar may have a sugar response to artificial sweeteners, which in turn causes a rise in blood sugar.

Everything seems to contain sugar when you are worried about your blood sugar levels. Diet soda is popular for people with diabetes, but does diet soda raise blood sugar levels?

Diet soda doesn't directly impact your blood sugar or A1C levels. However, learning more about the relationship between these things is a bit more complicated and may change your drink choices. 

Making healthy choices to avoid negatively affecting your blood sugar levels can get complicated. Before you decide whether to grab a diet soda, you need to know what happens when you eat and drink things like that. 

What is blood sugar?

Your body breaks down food into glucose (sugar) molecules. These sugar molecules move from your belly into your bloodstream, becoming your "blood sugar".

Blood sugar is the primary source of energy in your body. As it moves through your bloodstream, the sugar—energy—powers your cells, which lowers your blood sugar as it is used up.

In fact, blood sugar is the primary source of energy in your body. It moves throughout your body, depositing the energy into your body's cells.

What is insulin?

Insulin is like a key that opens the front door of your body's cells to let in glucose molecules. Your cells can't use glucose for energy without insulin.

Your pancreas releases insulin in response to high blood sugar levels. Problems with insulin production or efficiency, though, may lead to problems with blood sugar. 

If insulin isn't allowing your cells to process it, the blood sugar stays in your bloodstream and causes health problems.

What is A1C?

Your blood sugar level changes throughout the day, but regular testing can help you keep track of these changes. A1C tests reveal how much sugar has built up in your bloodstream over time.

When sugar is left behind in your bloodstream, it sticks to the hemoglobin molecules in your blood. The amount of this glucose stuck reflects the average blood sugar over about 3 months.

A1C tests are also referred to as hemoglobin A1C tests or HbA1c tests. These tests serve many purposes, but they mainly help diagnose diabetes and prediabetes.

Basics of diet soda

With all that out of the way, the next task is to look closely at your diet soda. Every soda is different, so you may need to shop for a soda that fits your needs.

Diet vs. regular soda

The exact ingredients in a soda will vary by brand. Most sodas have added sweeteners and sodium for flavor, though. 

Regular sodas often contain sugar or high-fructose corn syrup. Diet sodas have artificial sweeteners without significant nutrients, calories, or carbohydrates. These artificial sweeteners generally don't break down like other foods in your body, and their effects are often negligible. 

All diet sodas are different, though. They may be reduced sugar, zero sugar, or zero calories. Before drinking a diet soda, though, make sure it has one of the following approved artificial sweeteners:

Of course, not all artificial sweeteners are the same, and each may interact with your body differently. Through daily blood sugar testing and A1C testing, you and your doctor can figure out which artificial sweetener is ideal for your lifestyle. 

Artificial sweeteners and blood sugar

Non-nutritive, artificial sweeteners shouldn't usually cause your blood sugar to rise, but people who are overweight and have a lot of blood sugar may have a sugar response to artificial sweeteners, which in turn causes a rise in blood sugar. 

Talk with your doctor if you're concerned about artificial sweeteners and your blood sugar. 

The indirect impacts of diet soda

On the surface, diet soda isn't likely to directly raise your blood sugar, but most diet sodas aren't nutritionally "free" and may indirectly impact your blood sugar. 

Sodium 

Most soda has added sodium to improve the flavor. The sodium in a can of soda may not seem significant at a glance, but it adds up if you're an avid soda drinker.

Too much sodium can lead to high blood pressure. High blood pressure can then make you susceptible to diabetes. 

Sodium can also cause dehydration, which can cause spikes in blood sugar. Frequent dehydration and spikes in blood sugar can raise your A1C levels.

Caffeine

Some sodas have caffeine, particularly energy drinks, and people with diabetes may find that their blood sugar is sensitive to caffeine. Caffeine may raise blood sugar levels, so ask your doctor if you should opt for caffeine-free diet soda.

Zero-calorie sweetness

You may be thinking: "But diet soda doesn't have sugar!" It doesn't have sugar, but your brain still responds to it like it's sugary. 

This trickery may cause you to reach for another diet soda instead of water. It may also make it easier to grab a sugary snack.

Your brain treats sweetness like a reward. The more you give your brain rewards, the more it wants, and the more likely you are to consume some actual sugar. 

Flavor distortion

Artificial sweeteners are much sweeter than sugar and can distort your sense of taste. If you drink diet soda, other foods and flavors may become unappetizing, leading you away from healthier options.

Maintaining your blood sugar goes beyond what you drink. Your entire diet plays a role, and soda can control your diet indirectly. 

The skinny on diet soda

Diet soda is popular for people who are looking to watch their blood sugar levels. However, given soda's bad reputation, figuring out if you can drink it can be challenging. 

For most people, diet (sugar-free) soda is an excellent alternative to drinking regular soda. It may be even better, though, to try sparkling water, unsweetened flavored teas, or fruit added to water. Ask your doctor for tips

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Medically Reviewed on 2/8/2023
References
SOURCES:

Centers for Disease Control and Prevention: "10 Surprising Things That Can Spike Your Blood Sugar," "All About Your A1C," "What is Diabetes?"

Diabetes Care: "Sucralose Affects Glycemic and Hormonal Responses to an Oral Glucose Load."

Diabetes Education Online: "Artificial Sweeteners."

Diabetes & Metabolic Syndrome: "The effect of acute caffeine intake on insulin sensitivity and glycemic control in people with diabetes."

Harvard Health Publishing: "Artificial sweeteners: sugar-free, but at what cost?"

Johns Hopkins Medicine: "Facts About Sugar and Sugar Substitutes."

MedlinePlus: "Blood Sugar."

National Institute of Diabetes and Digestive and Kidney Diseases: "The A1C Test & Diabetes."