What happens if you only drink soda and no water?: The serious consequences of poor hydration

October 10, 2025 •

4 min read

According to a study reported at a European health conference, a woman who drank two liters of cola daily for 16 years was hospitalized with severely low potassium and heart problems. This extreme case highlights the devastating health outcomes of ignoring proper hydration by choosing to only drink soda and no water.

Quick Summary

A diet consisting exclusively of soda and no water can lead to a cascade of negative health effects. It impairs hydration, causes significant weight gain, increases the risk of type 2 diabetes, damages kidneys and teeth, and leads to mineral imbalances.

Key Points

Severe Dehydration: The diuretic effect of caffeine and the fluid-loss-inducing properties of high sugar content mean soda cannot effectively replace water, leading to chronic dehydration and electrolyte imbalance.
Kidney and Liver Damage: Regular soda consumption, especially cola with phosphoric acid, strains the kidneys and increases the risk of kidney stones and chronic kidney disease. High fructose corn syrup can also lead to fatty liver disease.
Metabolic Syndrome and Diabetes: The excess sugar intake from an exclusive soda diet is a major contributor to weight gain, obesity, and an elevated risk of developing insulin resistance and type 2 diabetes.
Dental Decay: The high acidity and sugar in both regular and diet soda erode tooth enamel and promote bacterial growth, causing irreversible dental erosion and cavities.
Mineral Deficiency: The lack of nutritional value in soda, combined with the way ingredients like phosphoric acid can interfere with calcium absorption, leads to deficiencies that compromise bone density over time.
Energy and Mood Fluctuations: Regular soda consumption causes blood sugar spikes and crashes, which can result in fatigue, irritability, and continuous sugar cravings.

The Body's Basic Need for Water

Water is essential for every physiological process, from regulating body temperature and lubricating joints to flushing out toxins and transporting nutrients. It constitutes approximately 60% of an adult's body weight and is critical for maintaining overall health. Substituting water with soda, whether regular or diet, replaces this vital, calorie-free fluid with a mix of sugars, acids, and artificial additives that offer no nutritional value.

Immediate Health Consequences

Even in the short term, replacing water with soda sends your body into a state of flux, triggered by the poor nutritional profile and chemical composition of soft drinks.

Dehydration: While soda contains water, its hydrating effect is minimal and can be counteracted by other ingredients. Many sodas contain caffeine, a diuretic that increases urine production, forcing your body to excrete fluid. High sugar content can also exacerbate fluid loss. This can leave you feeling chronically thirsty, ironically prompting you to drink more soda and worsening the cycle.
Energy Spikes and Crashes: The large amount of simple sugars in regular soda causes a rapid spike in blood sugar. The body then releases a surge of insulin to compensate, leading to a sharp drop in blood glucose that can leave you feeling tired, irritable, and hungry. This cycle of spikes and crashes contributes to fatigue and sugar cravings.
Digestive Discomfort: The carbonation and high sugar content in soda can irritate the digestive system, leading to issues like bloating, indigestion, and acid reflux. Excessive soda intake can also disrupt the balance of gut microbiota, impacting immunity and digestion.

The Devastating Long-Term Toll

Sustained soda-only consumption will progressively damage multiple organ systems, with effects ranging from chronic conditions to life-threatening disease.

Metabolic and Cardiovascular Disease

Without water, the liver is left to process a relentless flood of sugar. A meta-analysis of studies showed that increased consumption of sugary beverages was associated with a 16% higher risk of type 2 diabetes over a four-year period.

Weight Gain: Liquid calories from soda do not provide the same feeling of fullness as solid foods, leading to increased overall caloric intake. A single 12-ounce can of regular cola contains around 155 calories, almost all from added sugar. Replacing daily water intake with this amount can quickly lead to significant weight gain and obesity.
Type 2 Diabetes: The constant fluctuations in blood sugar and the liver's struggle to process excessive sugar can lead to insulin resistance, a key factor in the development of type 2 diabetes.
Heart Disease: High sugar intake is linked to elevated triglycerides, low levels of "good" HDL cholesterol, and high blood pressure, all major risk factors for heart disease and stroke.
Fatty Liver Disease: The high concentration of high-fructose corn syrup in many sodas can overwhelm the liver, which converts the excess fructose into fat, leading to non-alcoholic fatty liver disease.

Kidney Damage and Mineral Imbalance

Sodas, particularly dark colas, contain high levels of phosphoric acid. This chemical can promote the formation of kidney stones and contribute to chronic kidney disease. A case study highlighted how a patient's severely low potassium levels and heart problems were directly linked to exclusive soda consumption. These issues arose from electrolyte imbalances, which pure water helps to regulate.

Dental Destruction

Oral health is one of the most immediate and visible casualties of a soda-only diet. Both the sugar and acid in soda launch a dual-pronged attack on your teeth.

Enamel Erosion: The citric and phosphoric acids in soda soften tooth enamel, the protective outer layer of your teeth. Once enamel is lost, it cannot be replaced, leaving teeth vulnerable to decay.
Cavity Formation: Sugars in soda feed the bacteria in your mouth, which then produce more acid. With every sip, your teeth are subjected to a new acid attack, dramatically increasing the risk of cavities.

Weakened Bones

Research has shown that consuming high amounts of phosphoric acid, found in cola, can negatively impact bone health by altering the calcium-to-phosphorus ratio in the body. Forgoing calcium-rich beverages like milk for soda can reduce bone mineral density, particularly in women, increasing the risk of osteoporosis and fractures.

Soda vs. Water: A Comparison


Feature	Soda (Regular)	Water
Hydration	Minimal; caffeine can be dehydrating	Excellent; essential for all bodily functions
Calories	High (around 155 per 12oz can)	Zero
Sugar	High; leads to spikes and crashes	Zero
Dental Impact	Highly acidic and sugary; causes erosion and cavities	Excellent; cleanses mouth and contains strengthening fluoride
Kidney Health	Strains kidneys; increases risk of stones	Flushes toxins; prevents stones and aids function
Electrolytes	Imbalanced profile; can lead to deficiency	Regulates balance; crucial for nerves and muscles
Nutritional Value	Essentially none	Essential for life; aids digestion and delivery of nutrients

Conclusion

Replacing water with soda as your primary beverage can lead to significant and potentially life-threatening health problems. The lack of essential hydration, combined with the harmful effects of sugar and acids, impacts multiple organ systems, including the kidneys, liver, heart, and bones. Long-term consequences include an increased risk of obesity, type 2 diabetes, kidney stones, and severe dental decay. Choosing water over soda is crucial for maintaining proper bodily functions and overall well-being.(https://nutritionsource.hsph.harvard.edu/healthy-drinks/sugary-drinks/)

Frequently Asked Questions

Survival time would be highly dependent on individual factors like health and activity level, but it would not be long. Severe electrolyte imbalances and progressive organ failure due to malnutrition and dehydration would lead to premature death, likely sooner than starvation alone.

No. While diet sodas are calorie-free, they still contain acids that damage teeth and artificial sweeteners that may disrupt gut bacteria and metabolic function. Water is the best choice for proper hydration.

The caffeine content in most sodas is not high enough to cause immediate, severe dehydration. However, when consumed exclusively and in large quantities, its diuretic effect adds to the fluid imbalance caused by other factors, contributing to chronic dehydration.

Early signs include increased thirst, dry mouth, fatigue, headaches, mood swings, and a constant craving for sugar. You may also notice dark-colored urine and experience digestive issues like bloating or acid reflux.

Yes, regular soda consumption, particularly dark colas containing phosphoric acid, has been linked to an increased risk of developing kidney stones. High sugar intake and chronic dehydration also contribute to stone formation.

Water, especially fluoridated tap water, helps clean the mouth and strengthen enamel. Soda, however, is highly acidic and sugary, softening enamel and feeding bacteria that produce acids, leading directly to cavities and irreversible erosion.

Switching from soda to water can lead to rapid improvements. Many people experience weight loss, better hydration, increased energy, and a reduction in chronic health risks like diabetes and heart disease. A case study showed significant recovery in just one week.