A nutrient is a substance that provides essential nourishment for the growth and maintenance of living organisms. Nutrients are vital for various bodily functions, including energy production, immune system support, and tissue repair. They can be classified into two main categories: macronutrients, which include carbohydrates, proteins, and fats, and micronutrients, which consist of vitamins and minerals. Different foods contain varying types and amounts of nutrients. For example, fruits and vegetables are rich in vitamins and minerals, while grains and legumes provide carbohydrates and proteins. A balanced diet, which includes a variety of food groups, helps ensure that individuals receive all the necessary nutrients for optimal health.