Sugar is high in calories and low in nutritional value. So why wouldn't avoiding it completely be desirable?
The great thing about sugar is that, like fat, it can make food more enjoyable to eat. Part of eating is pleasure...why else would we have so many sensitive taste buds? Many people eat as though they are not avoiding sugar, nor fat, but pleasure. This can transfer over to other parts of their lives.
Restricting any food type rigidly (dieting) is a stepping stone to developing an eating disorder like anorexia nervosa. Eating sugar in moderation can be psychologically healthy.
