Does consuming more sugar increase the risk for cancer?

A recent study adds to a growing, but mixed, body of evidence examining whether sugar-sweetened beverages and other sources of sugar are associated with risk for cancer.

The study, published in Gastro Hep Advances, found that US nurses and other health professionals who drank more than one sugar-sweetened beverage a day had a nearly 2.5 fold higher incidence of gastric cancer than those who essentially steered clear.

But the findings were more nuanced than the striking 2.5 fold risk estimate that several news outlets highlighted.

The important context is that gastric cancer incidence was low overall, regardless of sugar intake. Across more than 112,000 participants who self-reported their dietary habits on food frequency questionnaires every 4 years, there were 16.3 gastric cancer cases for every 100,000 people followed for 1 year among those who had more than one sugar-sweetened beverage a day vs 7.7 cases among those who drank fewer than one a month.

While the broader literature does suggest that consuming sugar-sweetened beverages may increase the risk for several cancers, the strength of the evidence varies substantially by cancer type, and the findings are not sufficient to establish that sugary drinks cause cancer.

“I think it’s very difficult to test this in a human population in a way that will allow us to come up with concrete answers,” said Andrew T. Chan, MD, MPH, chief of the Clinical and Translational Epidemiology Unit at Massachusetts General Hospital, Boston, who led the gastric cancer study. The best available evidence “is sort of a preponderance of epidemiological studies.”

Nuances in the Evidence

The consumption of sugary drinks has increased globally over the past several decades, making questions about the potential link between sugary drinks and the risk for cancer increasingly relevant.

The NutriNet-Santé prospective cohort, published in The BMJ in 2019, remains among the most widely cited studies in this space. The study found that consuming sugary drinks was associated with an increased risk for cancer. More specifically, among more than 101,000 French adults tracked for a median of 5.1 years, each additional 100 mL/d of sugary drinks (roughly one third of a soda can) was associated with an 18% increased risk for cancer overall and a 22% increased risk for breast cancer.

After accounting for sugar content from those drinks, the association between sugary drink consumption and overall risk for cancer was no longer statistically significant.

The findings suggest that “a huge part of the association is actually driven by sugar,” said Bernard Srour, PhD, nutritional epidemiologist at the French National Institute of Health and Medical Research (Inserm), Paris, France, and corresponding author on the NutriNet-Santé study. Still, “I don’t think we can say that [sugar] is solely responsible.”

For instance, the study found that energy intake from sugary drinks was also associated with cancer, potentially making it difficult to separate the effects of sugar from those of overall caloric intake.

Additionally, the evidence isn’t equally strong across cancers. The NutriNet-Santé study found no significant association for prostate and colorectal cancers.

Research since the NutriNet-Santé study has added to the body of evidence. A 2021 meta-analysis that pooled data from 27 observational studies found significant associations between the highest, vs lowest, consumption of sugar-sweetened beverages and breast cancer (14% higher relative risk) and prostate cancer (18% higher), with borderline positive trends for colorectal and pancreatic cancers that did not reach statistical significance.

A formal review of evidence from the World Cancer Research Fund, posted as a preprint in July 2026, rated the evidence as supporting a probable causal association between sugar-sweetened beverages and pancreatic and colorectal cancer incidence, based on 158 publications from 51 cohorts, though found more limited evidence supporting a positive association between these beverages and risk for ovarian and endometrial cancers.

Overall, the evidence suggests that “our increasing consumption of sugary drinks is likely contributing to some of these cancer trends,” Chan said.

How Would Sugar Cause Cancer?

If the association is real, what is sugar doing?

Sugar-sweetened beverages are associated with greater obesity risk, and obesity is an established risk factor for at least 13 cancers. One potential pathway is that sugary drinks contribute to excess calorie intake and weight gain, which in turn can increase the risk for cancer.

However, weight gain may not fully explain the association.

When the NutriNet-Santé investigators examined whether the association could be explained by differences in body weight, the cancer associations held when participants were stratified by baseline BMI or weight gain during follow-up. And in a subset of about 15,600 participants who had more detailed measurements of body fat, higher sugary drink intake was also associated with greater visceral fat, which the authors suggested could contribute to the risk for cancer independent of body weight.

Srour said those results pointed away from weight gain as the full explanation but stopped short of ruling it out. “What we can’t say with confidence today is whether sugar leads to a higher cancer risk independently of adiposity,” he said.

But beyond weight, could sugar have a more direct effect on risk for cancer?

Emil Lou, MD, PhD, a gastrointestinal oncologist and cancer biologist at the University of Minnesota in Minneapolis, described a possible biological route to explain how sugar-sweetened beverage consumption could affect the risk for cancer: At the cellular level, high-glucose, high-inflammation conditions can dysregulate cells lining the gut, sending inflammatory signals that recruit neighboring cells into the same process.

“Day after day, year after year,” Lou said, the cumulative exposure creates “an inflammatory soup or recipe for cancer.”

But certainty on how exactly sugar intake might increase the risk for cancer remains out of reach.

Nearly all the evidence linking sugary drinks to cancer comes from observational cohorts. Participants report what they drink on questionnaires, and researchers follow them for years or decades, adjusting statistically for confounders like smoking, physical activity, BMI, and overall diet quality.

Randomized trials assigning people to long-term sugar-sweetened beverage consumption and measuring cancer endpoints would be impractical, potentially requiring decades of follow-up, Srour explained.

Not All Sugars Are Equal

The picture becomes more complex when researchers look beyond sugar-sweetened beverages as a category and examine different types and sources of sugar.

A 2018 systematic review of 37 prospective cohort studies found no association between total sugar and sucrose intake and the risk for cancer. A 2021 cohort analysis from the PREDIMED trial similarly found that sugar consumed in solid form was not associated with cancer incidence or mortality, whereas fructose from liquid sources was associated with overall risk for cancer.

Chan’s gastric cancer study provided further evidence on fructose, finding that higher total fructose intake was independently associated with gastric cancer incidence.

Evidence on artificially sweetened beverages and cancer, however, is mixed. In Chan’s gastric cancer study, diet drinks were not associated with a risk for cancer at any intake level. The NutriNet-Santé study also found no association between artificially sweetened beverage consumption and the risk for cancer. However, a subsequent analysis of the same NutriNet-Santé cohort that assessed artificial sweeteners from all dietary sources found that higher consumption was associated with a 13% higher risk for cancer overall, with stronger associations for aspartame and acesulfame-K.

Whole fruit has not been associated with an increased risk for cancer, whereas fruit juice appears to carry its own signal: in the NutriNet-Santé study, each additional 100 mL/d of 100% juice was associated with a 12% higher risk for cancer overall.

“We actually weren’t really expecting to see an association between 100% fruit juices and cancer,” Srour said. Many national dietary guidelines recommend limiting juice to a small serving a day, he noted, counting it as a replacement for one portion of fruit rather than as a free addition.

Putting the fruit juice vs whole fruit comparison into context: “If you eat an orange, you have to chew it, you have the fiber, you have the food matrix slowing digestion,” Srour said. “If you take five oranges and squeeze them into a glass, you drink them in less than 2 minutes. You would never eat five oranges in 2 minutes.”

What Clinicians Can Say Now

For clinicians, patients often ask two similar but fundamentally different questions: “Did sugar cause my cancer?” and “Is sugar feeding my cancer?”

Arturo Loaiza-Bonilla, MD, MSEd, said the latter, which is a progression question, is raised by patients constantly. A tumor “will eat anything that is on its way, glucose or fat or protein,”  he said, systemwide chief of hematology and oncology at St. Luke’s University Health Network in Bethlehem, Pennsylvania. So “nobody should take away milkshakes from their diet” due to fear of feeding cancer.

Patients undergoing treatment also need calories to tolerate therapy, he said, and there is no established evidence that restricting sugar improves outcomes for people who already have cancer.

On the prevention front, his recommendation to patients and their families who are concerned is to choose water and use diet drinks as a bridge to cut down on sugar consumption, especially for children and teenagers who have decades of potential exposure ahead. “This is a risk that doesn’t happen immediately,” said Loaiza-Bonilla, also chief medical officer at Massive Bio. “It’s years and years of exposure.”

Chan offered a similar view, with the caveat that drinking more sugary drinks does not mean a person will develop cancer. “We can all think of lots of people who drink plenty of sugar-sweetened beverages that have no health consequences,” he said.

Population-level associations do not translate to individual certainty, and no study can tell a specific patient that a specific sugar-intake habit caused or will cause a specific cancer.

Loaiza-Bonilla put it in terms he uses with families in his clinic, particularly those in the Hispanic community where gastric cancer rates are elevated. Decrease sugary drink consumption. “It really doesn’t cost anything to just cut down,” he said.

Chan reported serving as a consultant for Pfizer Inc. and Boehringer Ingelheim and receiving grant support from Freenome Holdings outside the submitted work. Lou reported having financial interests in Ryght, Inc. He reported having consulting or advisory roles with Myer Research, Inc.; Primum; and Impiricus. Srour and Loaiza-Bonilla reported no relevant financial relationships.