The main source of energy for the brain is glucose, a simple sugar derived from carbohydrates. The brain requires a constant supply of glucose to function optimally, as it relies on this energy source for various cognitive processes, including decision-making, memory, and learning. While healthy fats and proteins can also contribute to overall energy levels, maintaining balanced carbohydrate intake is vital for sustained brain health and effective mental performance. Regular meals and snacks containing complex carbohydrates can help ensure adequate glucose levels.