Candy bars are incredibly unhealthy. They are high in sugar, refined wheat flour and processed fats. They are also very low in essential nutrients.
Processed foods like candy bars are generally engineered to be super tasty (so you eat more), and have been designed so that it’s very easy to eat them quickly.
A candy bar may taste good and cause some short-term satiety, but you’ll be hungry again very quickly because of the way these high-sugar treats are metabolized.
Alternatives: Eat a piece of fruit instead, or a piece of real high-cocoa dark chocolate (75% or higher).