Eating too much sugar, even developing into what some have termed "sugar addiction" has several potential harms to kids, both physical and psychological.
The physical harms of too much sugar include obesity, malnutrition and tooth decay. While it is widely known that too much sugar can cause people to put on weight, parents may be surprised to learn that even overweight kids can suffer from malnutrition. And tooth decay can potentially cost your child much more than the need for fillings -- it can lead to severe illness, and in extreme cases, even death.
Eating too much sugar, for example, eating candy on a daily basis, also has potential psychological harms. One particular study showed a clear link between daily candy consumption in ten-year-olds and violence in later life. This research looked at a sample of individuals at age 10 and then later in adulthood. Their daily candy consumption as a child was assessed. The researchers found that, of those who committed violent crimes, nearly 70% ate candy every day as children, compared to 42% who did not go on to commit violent crimes.
The authors of the study speculated that this phenomenon is related to parents using candy to control their children's behavior, which gets in the way of children learning to delay gratification. Other research has shown that not being able to delay gratification is related to delinquency. As well as giving kids too much sugar, candy also contains additives which have been found to promote aggression.
Although giving your son candy might seem like the easiest way to get him to do what you ask, you could very well be setting him up for problems by giving him too much sugar. Try using effective discipline methods instead.