Q. Does the cooking have a negative effect on the protein content of the food? I have heard that high temperatures cooking breaks the protein, so does the cooking have a negative effect on the protein content of the food? A. Yes. Proteins can be denatured by heat, but only when the protein structure is delicate or is exposed to extremely high temperatures for long time. You must remember that breaking of protein is the physical-chemical process where the physical or chemical structure of a protein is rearranged. So cooking will not reduce on the nutritive value of the food until it’s cooked at cooking temperatures.