Food nourishes everything, from animals to plants. Even microbes need food. Food even nourishes fetuses before they are born and is supplied by mothers. Babies need food for their physical and mental growth and to keep them healthy. Children and adults derive energy needed for their activities as well as keeping them strong.
Food consists of nutrients including proteins, carbohydrates and fats, which are called macronutrients as they in larger amounts in foods. Vitamins and minerals are called micronutrients as they are present in small amounts.
Humans used to hunt and gather food like other animals but then they decided that it is better to grow their own food by agriculture so they could have food anytime and anywhere they need. They started growing crops, raising farm animals and would also get fish and seafood.
Food Science Nutrified 