Many health experts warn to avoid consuming edible oil that has been cooked many times. Used cooking oil is associated with several life-threatening diseases like heart disease, respiratory issues, etc.
According to research in 2016, reheated cooking oil has a greater peroxide value than unheated oil. Therefore, this can be responsible for cancer in humans. Moreover, when fruits, vegetables, meat, or dairy products come in the oil’s contact, it's prone to contamination. Thus, using unheated or singly heated oil is advisable.