how food is utilized during nutrition process?
Nutrition and respiration are two different things. Respiration is the cellular process by which a living thing extracts energy from food. Nutrition is the process by which a living thing takes in food in the form of macronutrients or as vitamins and minerals so that it can use these nutrients for its cellular processes.
So, in short, food is converted to stored energy in digestion process and energy released in respiration.