This document provides an introduction to nutrition. It defines food and nutrients, and explains the functions of food. It then defines nutrition and discusses the role of nutrients and macronutrients and micronutrients. It also discusses Indian food customs and habits, as well as factors that affect nutrition and meal planning such as age, sex, income, occupation, culture, religion, food availability, and food laws. Finally, it discusses changing concepts in food and nutrition and factors responsible for changing India's nutritional scenario such as population growth, urban migration, mechanization, and economic development.