Around 25 % protein is a good starter then remaining fat, macros should be high when following a ketogenic diet and higher carbs if on a typical standard diet. (lowcarbalpha.com)
Strain remaining fat into an airtight container; cover and reserve for another use (like roasting potatoes). (epicurious.com)
Toss potatoes and 1/4 cup duck fat in roasting pan (save remaining fat for another use); season with salt and pepper. (bonappetit.com)