High-Fat Diet Linked to Liver Changes and Increased Cancer Risk

Long-term consumption of high-fat diets, including fast food and ultra-processed snacks, may lead to significant biological changes in the liver, potentially increasing the risk of cancer. Researchers at the Massachusetts Institute of Technology (MIT) found that it is not only the quantity of fatty food consumed that matters but also the duration of exposure to such diets. Their study, published in December 2023 in the journal Cell, indicates that chronic high-fat intake may push liver cells into a survival mode, making them more susceptible to cancerous changes.

The research focused on mice subjected to a long-term high-fat diet, some of which developed liver cancer. As the liver cells processed large amounts of fat repeatedly, they shifted from their normal functions—breaking down nutrients and filtering toxins—to a more primitive state aimed at survival. This transformation is connected to tumorigenesis, the process by which cancer can develop.

Alex K. Shalek, a senior author of the study and director of MIT’s Institute for Medical Engineering and Sciences, commented, “If cells are forced to deal with a stressor, such as a high-fat diet, over and over again, they will do things that will help them survive, but at the risk of increased susceptibility to tumorigenesis.”

The study observed a decline in healthy liver functions as the disease progressed in the mice. When researchers examined human liver samples, they found similar declines in normal liver activity, although long-term cancer outcomes were not tracked. Co-first author and MIT graduate student Constantine Tzouanas explained, “These cells have already turned on the same genes that they’re going to need to become cancerous.” He added that once a cell acquires the wrong mutation, it can rapidly develop cancerous traits.

The findings contribute to understanding why fatty liver disease often precedes liver cancer and highlight the long-term impact of dietary habits. The researchers noted that patients whose liver cells exhibited more stress-related changes and less normal function had shorter life expectancies after a cancer diagnosis. While this process occurs over about a year in mice, it is estimated that similar changes may take decades in humans.

The research emphasizes that these findings pertain to long-term dietary habits rather than occasional indulgences. Although the study did not focus on specific foods, experts generally advocate for moderation and balanced eating patterns. Dr. Ghassan Abou-Alfa, an oncologist specializing in gastrointestinal cancers at Memorial Sloan Kettering Cancer Center, cautioned that the results should be interpreted with care, as they were primarily based on animal models.

Despite these reservations, the study sheds light on the biological mechanisms that may explain the progression from fatty liver disease to liver cancer, a condition that can affect individuals who are not severely obese. “This can be any of us, and we need to adapt our lifestyles to avoid turning healthy liver cells into cancer cells,” Abou-Alfa stated.

Dietitians emphasize that while there is no guaranteed way to prevent cancer, certain lifestyle changes can potentially reduce risk. Karen Smith, an oncology dietitian at Texas Oncology, noted, “Your overall lifestyle matters more than any single food.” She advised maintaining a healthy weight, avoiding smoking, and staying physically active. Additionally, she suggested limiting red and processed meats while opting for proteins such as fish, chicken, beans, and lentils, coupled with a balanced intake of fruits, vegetables, whole grains, and legumes.

The MIT team acknowledged that their findings largely stem from mouse studies and early genetic changes. They do not provide a complete explanation of how disrupted fat metabolism leads to cancer and do not consider factors such as insulin resistance, inflammation, or alcohol consumption. Future research will investigate whether transitioning to healthier eating habits or employing GLP-1 weight loss medications can restore normal liver cell behavior and reduce cancer risk.

Previous studies have also indicated that long-term high-fat diets can disrupt communication between the gut and brain, affecting appetite, mood, and metabolism. As the conversation around diet and health continues, these latest findings underscore the importance of long-term dietary choices in relation to liver health and cancer risk.