Study finds animal-based fats fuel tumor growth in obese mice, plant fats do not

Medical Xpress / Ludwig Institute for Cancer Research / Nature Metabolism ^ | July 30, 2025 | Britta Kunkemoeller et al

[ConservativeMind]

Obesity elevates the risk of cancer. But it has long been unclear whether these effects stem from the fat in people or from dietary fats they consume.

Now, Lydia Lynch has provided a compelling answer.

"Our study reveals that the source of dietary fat, not adiposity itself, is the primary factor that influences tumor growth in obese mice," said Lynch. "We found that high-fat diets derived from lard, beef tallow or butter compromise anti-tumor immunity and accelerate tumor growth in several tumor models of obese mice. Diets based on coconut oil, palm oil or olive oil, meanwhile, do not have this effect in equally obese mice."

Lynch and others have previously shown obesity induces changes in the immune system and in the microenvironment of tumors that contribute to tumor progression. It does so by impairing the body's cancer surveillance system, undermining the ability of immune cells—namely cytotoxic T cells (CTLs) and natural killer (NK) cells—to infiltrate tumors and, once there, kill their cancerous quarry.

The researchers identified several metabolic intermediates of dietary fats, especially long-chain acylcarnitine species, potently suppress NK cells and CTLs. These metabolites were especially elevated in obese mice reared on butter, lard and beef tallow diets, but not in obese mice on plant-fat diets. They report that in CTLs, the molecules cause deep metabolic dysfunction in organelles known as mitochondria—the powerhouses of cells. This saps anti-tumor CTLs of their vitality, undermines their production of a factor (IFN-γ) critical to their function and disables their cell-killing machinery.

The palm oil-based diet prevented metabolic paralysis in the NK cells of obese mice, apparently by amplifying the activity of a master regulator of cellular metabolism known as c-Myc. The researchers found that Myc expression was reduced in mice fed animal fat—and also in NK cells from people living with obesity.

[maddog55]

I’ll take animal fat any day to plant fat any day.... I’ll take the risk.

[Openurmind]

Absolute PETA Vegan agenda propaganda BS.

[KittyKares]

What is a healthy diet seems to keep changing, which is very confusing. People swear by the Keto diet. Vegetarians swear by theirs. I suspect it’s best to be somewhere in the middle.

[moonhawk]

Are you a man or a mouse?