Which soda is harmful? A look at ingredients and effects

December 30, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), about half of all adults in the U.S. consume at least one sugar-sweetened beverage per day. Understanding which soda is harmful involves looking beyond the sugar content to consider artificial sweeteners, acids, and other chemical additives.

Quick Summary

An analysis of the ingredients and health impacts of various sodas, comparing the risks associated with high-fructose corn syrup, artificial sweeteners, and phosphoric acid. It covers dental erosion, metabolic issues, and potential long-term risks.

Key Points

Sugary Sodas: High sugar content, often from high-fructose corn syrup, is linked to weight gain, type 2 diabetes, and fatty liver disease.
Diet Sodas: Artificial sweeteners can disrupt the gut microbiome, increase sugar cravings, and, surprisingly, elevate the risk of liver disease even more than regular soda.
Phosphoric Acid: This additive, common in colas, contributes significantly to dental enamel erosion and can affect bone density by leaching calcium from the body.
Metabolic Impact: Both sugary and diet sodas are associated with metabolic syndrome and an increased risk of cardiovascular complications.
Best Alternatives: Healthier options include water, unsweetened herbal teas, and sparkling water, which avoid the harmful additives found in most sodas.

The Double-Edged Sword: Sugar-Sweetened Sodas

While often thought of as the primary health concern, the massive amount of added sugar in traditional sodas presents a significant and well-documented risk. A standard 12-ounce can of cola can contain as much as 39 grams of sugar, the equivalent of almost 10 teaspoons. This liquid sugar is rapidly absorbed by the body, leading to a host of problems.

High-Fructose Corn Syrup vs. Cane Sugar

Many popular sodas are sweetened with high-fructose corn syrup (HFCS), a topic of much nutritional debate. HFCS is more lipogenic than cane sugar, meaning it can metabolize into fat molecules more readily. Regardless of the type, the sheer quantity of sugar in a single serving is problematic. For instance, Mountain Dew, known for its high sugar content, is often cited as particularly harmful to dental health due to this factor combined with high acidity.

Key Health Risks from Sugar-Sweetened Sodas

Weight Gain and Obesity: The empty calories from sugary drinks do not provide satiety, leading to overconsumption and contributing to weight gain.
Type 2 Diabetes: Consuming just one to two cans of soda per day can increase the risk of developing type 2 diabetes by 26%.
Fatty Liver Disease: Excess sugar is processed by the liver, and over time, this can lead to non-alcoholic fatty liver disease (NAFLD).
Dental Decay: The combination of sugar and acid creates a perfect storm for bacteria to thrive in the mouth, leading to cavities and enamel erosion.

The Deceptive Lure of Diet Sodas

For years, diet sodas were marketed as a healthier, guilt-free alternative. However, recent studies and growing evidence suggest that zero-calorie does not mean zero-risk. The danger lies in the artificial sweeteners used to mimic sugar's taste.

Artificial Sweeteners and Their Effects

Common artificial sweeteners include aspartame, sucralose, and acesulfame potassium. Some research suggests these compounds can have negative effects on gut health by disrupting the microbiome, which is crucial for nutrient absorption and immune function. Other studies point to a link between artificial sweeteners and increased cravings, potentially leading to weight gain despite the lack of calories.

The Surprising Liver and Metabolic Risks

A recent study published in the Times of India revealed that daily consumption of diet soda might pose a greater risk for metabolic dysfunction-associated steatotic liver disease (MASLD) than regular soda. Researchers found a 60% higher chance of developing MASLD in diet soda drinkers, compared to a 50% higher risk for regular soda consumers, challenging the long-held perception of diet sodas as the safe option.

The Unseen Threat: Phosphoric Acid

Beyond sugar and artificial sweeteners, a less-discussed ingredient poses a serious risk: phosphoric acid. This chemical gives many colas their signature 'bite' or tangy flavor. Its high acidity is a primary culprit behind dental erosion.

Bone Density and Kidney Health

The acidic nature of phosphoric acid has been linked to potential bone health issues. Studies have found that it can leach calcium from bones, which may increase the risk of osteoporosis and fractures, especially in individuals with excessive intake. High levels of phosphorus in the blood (hyperphosphatemia), which can occur with overconsumption, are also a known risk factor for kidney damage.

Comparison of Harmful Soda Ingredients


Feature	Sugary Sodas	Diet Sodas	Shared Concerns
Primary Harmful Ingredient	High-Fructose Corn Syrup (HFCS) or Sugar	Artificial Sweeteners (e.g., Aspartame)	Phosphoric Acid, Citric Acid
Metabolic Impact	Significant blood sugar spikes, high calorie load leading to weight gain and diabetes risk.	Potential for metabolic disruption, increased cravings, gut microbiome changes.	Risk of metabolic syndrome and cardiovascular complications.
Dental Health Impact	High sugar and acidity accelerate enamel erosion and cavities.	High acidity erodes tooth enamel, though less prone to cavities due to lack of sugar.	Enamel erosion is a risk factor for both types.
Long-Term Risks	Increased risk of obesity, type 2 diabetes, and fatty liver disease.	Potential link to liver disease, increased cravings, and neurological issues for sensitive individuals.	Potential for bone density loss and kidney problems from phosphoric acid.

Conclusion: Which soda is harmful?

Ultimately, determining which soda is harmful is not a simple choice between regular and diet versions, as both carry significant health risks. Sugary sodas are notorious for their empty calories and contribution to metabolic diseases, while diet sodas, despite their zero-calorie appeal, are now linked to metabolic issues, altered gut health, and liver risks. The common denominator of phosphoric acid and other additives contributes to dental decay and potential bone density problems across many varieties. The safest and most health-conscious approach is to view all sodas, both sugary and diet, as occasional treats rather than daily staples. Replacing them with water, herbal teas, or sparkling water is the most effective way to protect your long-term health.

For more detailed nutritional information and the potential risks of various food additives, the Environmental Working Group (EWG) provides a comprehensive resource. EWG - Harmful Food Additives

Frequently Asked Questions

Not necessarily. While they contain zero calories, artificial sweeteners in diet sodas can still impact your metabolism and increase sugar cravings, which may lead to weight gain. Recent studies even show a higher risk of liver disease for daily diet soda drinkers compared to regular soda drinkers.

Yes, phosphoric acid, found in many colas, is highly acidic and can erode tooth enamel over time, leading to decay. Furthermore, excessive intake has been linked to the leaching of calcium from bones, potentially contributing to lower bone density and increased fracture risk.

Excessive sugar from regular soda forces the liver to convert it into fat, which can cause non-alcoholic fatty liver disease (NAFLD). Surprisingly, some studies suggest diet sodas may pose an even greater risk for liver issues like MASLD.

Determining the single most harmful soda is difficult, as both sugary and diet options have significant risks. Sodas with extremely high sugar and caffeine content, like some energy drinks or specific brands such as Mountain Dew, are often cited for their heightened dental and metabolic risks.

Occasional and moderate consumption is less likely to cause severe health issues than regular, high-volume intake. However, it is important to be mindful that even small amounts contribute to overall sugar and acid exposure. Reducing intake is always recommended for better health.

While natural sweeteners are often considered a better alternative, research is still mixed on their long-term effects. The main benefit is the absence of sugar and artificial chemicals, but it's still best to rely on water and whole foods for hydration and nutrition.

Excellent alternatives to soda include plain water, sparkling water infused with fruit, herbal teas, or kombucha. These options provide flavor and hydration without the health risks associated with high sugar or artificial ingredients.