A massive new study suggests sugary drinks may increase liver cancer risk. The good news? Diet soda wasn’t linked to the same problem.

For years, sugary drinks have been public enemy #1 in the nutrition world.

Weight gain. Diabetes. Fatty liver disease.

The rap sheet is already pretty long.

Now, one of the largest studies ever conducted on beverage consumption and liver cancer has added another potential concern to the list.

Researchers analyzed data from more than 1.5 million adults across 11 long-term studies and found that people who drank more sugar-sweetened beverages (SSBs) had a higher risk of developing the two most common forms of liver cancer.

Meanwhile, despite years of controversy surrounding artificial sweeteners and aspartame, diet beverages were not associated with increased liver cancer risk after researchers accounted for factors like obesity and diabetes.

Let’s break down what they found—and what it means for your next trip to the refrigerator.

Why Liver Cancer Is Becoming a Bigger Problem

Liver cancer doesn’t get as much attention as breast, prostate, or colon cancer.

But maybe it should.

It’s currently the third leading cause of cancer-related death worldwide, and experts predict liver cancer cases could increase by more than 50% by 2040.

In the United States alone, more than 42,000 new cases are expected this year.

Traditionally, liver cancer has been linked to:

  • Hepatitis B
  • Hepatitis C
  • Heavy alcohol use
  • Smoking
  • Exposure to toxins like aflatoxin

But those risk factors don’t explain everything.

Researchers estimate that roughly one-third of liver cancer cases occur without any obvious explanation.

That’s why scientists have started looking more closely at diet.

The Great Diet Soda Debate

In 2023, the International Agency for Research on Cancer (IARC)—the cancer research arm of the World Health Organization—classified aspartame as “possibly carcinogenic to humans.”

That announcement generated headlines worldwide.

The classification sounded alarming.

But here’s the important nuance:

“Possibly carcinogenic” means the evidence is limited and far from conclusive.

The IARC decision was based largely on a handful of observational studies that suggested a possible link between artificially sweetened beverages and a type of liver cancer called hepatocellular carcinoma (HCC).

Scientists wanted a clearer answer.

So they pooled data from over 1.5 million people.

The result?

After adjusting for factors like obesity and diabetes, artificially sweetened beverages were not associated with an increased risk of liver cancer.

In fact, researchers found that people who drank the most diet beverages were also more likely to have diabetes and higher body weights.

Once those factors were accounted for, the apparent cancer connection disappeared.

In other words:

It may not have been the diet soda itself.

It may have been the underlying health conditions common among people who choose diet drinks.

The Real Concern Was Sugar

While diet beverages largely escaped blame, sugary drinks didn’t.

Researchers found that higher consumption of sugar-sweetened beverages was associated with increased risk of both major liver cancer subtypes:

Hepatocellular Carcinoma (HCC)

The most common form of liver cancer, accounting for roughly 75–85% of cases.

Intrahepatic Cholangiocarcinoma (ICC)

A less common but often aggressive cancer that develops in bile ducts inside the liver.

The increased risk wasn’t enormous.

This wasn’t a “drink one soda and get cancer” story.

But the association was consistent across multiple large populations and aligns with what scientists already know about sugar’s effects on liver health.

Why Would Soda Affect the Liver?

Your liver is essentially your body’s biochemical processing plant.

Everything you eat or drink eventually passes through it.

When it comes to sugary beverages, one ingredient gets special attention:

Fructose.

Unlike glucose, which is used throughout the body, fructose is processed primarily in the liver.

And that can create problems.

Researchers believe excessive fructose intake may:

  • Increase fat production inside the liver
  • Promote fatty liver disease
  • Increase insulin resistance
  • Trigger inflammation
  • Impair normal fat metabolism

Some scientists even describe fructose metabolism as behaving similarly to alcohol in certain ways.

That’s one reason non-alcoholic fatty liver disease—now called MASLD (Metabolic Dysfunction-Associated Steatotic Liver Disease)—has become increasingly common.

And MASLD itself is a major risk factor for liver cancer.

It May Be About More Than Weight Gain

One of the more interesting findings is that sugary drinks may affect the liver through mechanisms beyond simply causing obesity.

Even after researchers adjusted for body weight and diabetes, the association between sugary drinks and liver cancer remained.

Scientists suspect several possibilities:

Fatty Liver Formation

Excess fructose can directly increase fat accumulation in liver cells.

Chronic Inflammation

Over time, inflammation can damage liver tissue and promote cancer development.

Gut Barrier Disruption

Animal studies suggest high fructose intake may increase intestinal permeability, allowing bacterial toxins to reach the liver more easily.

Insulin and Growth Signaling

Persistently elevated insulin levels may create an environment that favors cancer growth.

Researchers are still sorting out exactly which mechanism matters most.

The answer is likely “all of the above.”

So Is Diet Soda Safe?

This study doesn’t prove that artificially sweetened beverages are perfectly harmless.

It simply found no convincing evidence that they increase liver cancer risk.

That’s an important distinction.

Scientists continue to study artificial sweeteners for potential effects on:

  • Gut bacteria
  • Metabolism
  • Appetite regulation
  • Long-term health outcomes

But when it comes specifically to liver cancer, this large analysis found no meaningful association.

That finding challenges the idea that aspartame is a major driver of liver cancer in humans.

What Should You Drink Instead?

The researchers weren’t conducting a beverage popularity contest.

But the practical takeaway is fairly straightforward.

If your goal is protecting long-term liver health:

Reducing sugar-sweetened beverage intake is probably a smart move.

That includes:

  • Regular soda
  • Sweet tea
  • Energy drinks
  • Fruit punches
  • Sugar-sweetened sports drinks

Water remains the gold standard.

Unsweetened tea and coffee also have surprisingly strong evidence supporting liver health.

And if someone uses a diet beverage to replace multiple sugary drinks each day, current evidence suggests that’s likely a net positive for liver health.

The Bottom Line

The biggest headline from this study isn’t about aspartame.

It’s about sugar.

After analyzing more than 1.5 million people, researchers found that higher consumption of sugar-sweetened beverages was linked to a greater risk of the two most common forms of liver cancer.

Artificially sweetened beverages, on the other hand, showed no significant association with liver cancer risk after accounting for obesity and diabetes.

That’s not a green light to live on diet soda.

But it does suggest that when it comes to liver cancer, the bigger threat may still be the sugar—not the sweetener.

Pharmacist’s Take

For years, nutrition debates have focused heavily on artificial sweeteners. Meanwhile, the evidence against excess sugar keeps getting stronger.

This study adds another piece to a growing body of research showing that the liver pays close attention to what we drink.

The takeaway isn’t that an occasional soda is dangerous.

It’s that daily habits matter.

If you’re looking for one simple change that could benefit your weight, blood sugar, fatty liver risk, and potentially even liver cancer risk, cutting back on sugary beverages remains one of the highest-return health investments you can make.

Watling CZ, Zhao L, Zhang X, Deubler E, Gonzalez-Feliciano AG, Graubard BI, Petrick JL, Wojt A, Butera G, Hofmann JN, Beane Freeman LE, Shrubsole MJ, Zheng W, Sudenga SL, Schernhammer E, Eliassen AH, Mucci LA, Sesso HD, Sinha R, Loftfield E, Um CY, McCullough ML, Jenab M, Zhang X, McGlynn KA. Artificially Sweetened and Sugar-Sweetened Beverage Intake and Risk of Liver Cancer. JAMA Netw Open. 2026 Jun 1;9(6):e2617754. doi: 10.1001/jamanetworkopen.2026.17754. PMID: 42268607; PMCID: PMC13254733.