Quick Facts

• High-fat conditions made triple-negative breast cancer tumors grow larger and more invasive than high-glucose, high-insulin, or high-ketone environments
• The study used 3D tumor models that mimic real human blood composition rather than traditional lab conditions
• High-fat environments increased MMP1 enzyme expression, which helps cancer cells break down tissue barriers and spread

A new Princeton University study challenges the common belief that sugar is the primary dietary concern for cancer patients. Researchers found that high-fat conditions fuel aggressive breast cancer growth more effectively than high-sugar environments.

The study, published in APL Bioengineering in March 2026, focused on triple-negative breast cancer, a particularly difficult-to-treat subtype. Scientists created three-dimensional tumor models and exposed them to four different nutrient environments that mirror human dietary states: high-insulin, high-glucose, high-ketone, and high-fat.

“We took the approach of building identical engineered tumors and culturing them in conditions that mimic the blood composition of patients under different dietary states,” said Professor Celeste Nelson, the study’s lead author. “We were hoping to identify dietary conditions that would slow tumor growth. Instead, we found one dietary condition – a high-fat diet – that sped up tumor growth.”

The high-fat environment produced tumors that grew larger and became more invasive than those in other conditions. The other metabolic states did not produce the same aggressive effects.

Researchers identified a key mechanism behind this phenomenon. High-fat conditions increased expression of matrix metalloproteinase 1 (MMP1), an enzyme that breaks down the structural framework surrounding cells. When this matrix breaks down, cancer cells can more easily migrate and invade nearby tissue.

The study’s methodology represents a significant advancement in cancer research. Traditional cell cultures use media saturated with sugars and biochemicals at levels that don’t match human blood composition.

“Our study shows that tumor cells behave differently when cultured in media that matches the biochemical composition of human plasma,” Nelson explained.

This finding contradicts the widespread focus on sugar as the primary dietary cancer concern. The National Cancer Institute states there is no evidence that consuming sugar makes cancer grow, despite cancer cells consuming more glucose than normal cells.

The research team plans to expand their work to test whether tumors respond differently to chemotherapy under various dietary conditions. This could lead to personalized dietary recommendations during cancer treatment.

“This would allow physicians to potentially make recommendations about what a patient should eat if prescribed a specific therapy,” Nelson said.

Supporting research from other institutions reinforces these findings. Studies have shown that specific dietary fats, particularly omega-6 fatty acids found in seed oils and animal products, enhance triple-negative breast cancer growth in mouse models.

The study doesn’t suggest that eating fat automatically accelerates cancer growth in people. Human metabolism involves complex interactions between diet, hormones, and lifestyle factors that extend far beyond any laboratory model.

However, the research provides valuable insights into how nutrient environments shape tumor behavior at the cellular level. The innovative experimental platform could help scientists test additional questions about cancer treatment and dietary interactions.

Read more: This One Dietary Condition Fueled Cancer Cells — And It Isn’t Sugar