Question

why is cooking food an irreversible change

Answer 1

Due To The Fact That It Is A Chemical Change Which Are Irreversible.
See,While Cooking, The Food Absorbs Heat And An Endothermic Reaction Takes Place And Thus After The Reaction The Product Has Completely Different Chemical Properties Than The Uncooked Food,Thus Making The Process A Chemical Change.And As Stated Above,A Chemical Change Is Irreversible As The Substance Changes To Form A New Substance.
Hope It Helped.

Answer 2

Why is cooking food an irreversible change ? This is because while cooking food, the properties of the ingredients and substances gets altered which makes it impossible to recover the original substance back. Therefore, due to this reason it is regarded as a kind of irreversible change.