Question

why are we suggested not to take too hot or too cold food material

Answer 1

Too hot will cause you to scald yourself. Too cold will cause you to get frostbite.

Answer 2

too hot food would increase the temperature of ur body n as a result there will be an increased activity of acid in ur stomach which will result in production of high amount of heat in ur body n u'll start sweating. N n it will also result in acidity.

now if u take cold food then that would result in decrease in the body temperature. now the temperature has reduced then the stomach will have to 1st bring the food to the normal body temperature n then it must start it's digestion process. this may also result in freezing ur stomach lining for some time.