No, because that quick lift is followed by an equally sudden letdown. Simple carbohydrates, such as the sugar in candy bars, enter the bloodstream almost immediately, causing a very high level of glucose, or blood sugar. This fast rise in glucose stimulates the pancreas to secrete a great deal of insulin to process the excess glucose and put it in storage as glycogen or fat. As the glucose is stored, there is a rapid drop in the amount left in the bloodstream. This lowered blood sugar produces the "sugar blues," a feeling of depression or low energy experienced 20 to 60 minutes after the initial burst of energy released by eating candy or other sugary food.
Sugared breakfast cereals, as well as candy bars and sodas, contain large amounts of sugar and may generate these erratic swings in blood sugar. The insulin is looking for more sugar to process, and you feel the urge to eat another candy bar to cheer yourself up.
What's really happening is that your blood sugar levels are bouncing up and down instead of maintaining a steady level as they would if you regularly ate complex carbohydrates and protein. This would give you even levels of blood sugar by slowly releasing glucose into the bloodstream from storage as it is needed. Since blood sugar is the immediate fuel your brain uses, it is important to maintain a steady supply.