Nutrition can be broadly defined as the study of nutrients and how the body uses them. Nutrients are broken down by the body, provide nourishment and energy. Macronutrients are the main types of nutrients the body needs in large amounts to thrive. There are three main types of macronutrients: carbohydrates, fats, and proteins. Each plays a role in providing benefits to the body. Carbohydrates provide quick energy (example sources include potatoes, bread, and fruit), fats provide structure to cell membranes (example sources include avocado, olives, and nuts), and proteins are the building blocks of muscle tissue (example sources include chicken, tofu, and eggs). There are also many micronutrients, or vitamins and minerals, that are needed in lesser amounts. Micronutrients are smaller molecules in food that the body also needs to support overall energy and health. Nutrition is necessary for all living beings to grow, heal, and thrive.