When people eat more saturated fat, their risk of dying goes up a bit—and part of that risk (about 10%) is because their body shows more inflammation, measured by a blood test called NPAR. When they eat more healthy fats, their risk goes down, and about 12% of that benefit is also linked to this same blood test.

This study found that eating more bad fats (saturated) raises your risk of dying, and eating more good fats (polyunsaturated) lowers it—and part of why this happens is because these fats change your body’s inflammation levels, measured by NPAR. The study says NPAR explains about 10% of these effects, which is exactly what the claim says.