The difference between simple and complex carbohydrates lies in their chemical structure and how the body processes them. Simple carbohydrates consist of one or two sugar molecules and are quickly absorbed by the body, providing immediate energy but leading to rapid fluctuations in blood sugar levels. Examples include sugar, honey, and fruit. In contrast, complex carbohydrates have longer chains of sugar molecules, taking longer to digest and providing sustained energy. Whole grains, legumes, and vegetables fall under this category, offering more nutrients and fiber.