Relationship between dietary fiber to carbohydrate ratio and mortality risk in US adults: NHANES 2007–2018

•Diets with higher fiber/carbohydrate ratio were related to lower mortality risk.•Such diets were also associated with lower cardiovascular and cancer mortality risk.•The associations were observed for diets with ≥45 % calories from carbohydrate.•Use of fiber/carbohydrate ratio may help reduce chronic disease risk and mortality.