Candy is rich in simple sugars that can be quickly digested and absorbed into your bloodstream, so you may feel an extra lift soon after eating a candy bar. In contrast, yoru body must take the time to convert more complex carbohydrates (such as are found in a potato or piece of bread) into glucose before they can be used for energy.
On the negative side, a typical candy bar consists of empty calories and does not provide your metabolism with valuable vitamins and minerals. Nor does it furnish long-lasting energy; an hour or so after munching on the candy bar you may be hungry again or feel a psychological and physical letdown because of the sudden drop in your blood sugar level.
** Asian Recipes