Most cooking oils are vegetable oils. Just like linseed oil most of them are « self drying », they’ll polymerize with time. Think « oil painting ». It might get sticky or build up unpleasantly if you are unlucky. I would be very careful with that. However, olive oil is allegedly very good for the skin, and moisturizing your fingers with a tiny drop of oil is not the same as wiping the whole guitar with it, it should be safe. Animal grease is not self drying, so you should be good with chicken, salami and whatnot. I’ve heard that earwax has the most remarkable waxing properties, the grease that you find on you nose too... I’ll stick with Fast Fret.