Fruit should not be eaten while dieting, because fructose is easily converted to fat.
This is a misconception. First, fruit is relatively low in fructose compared to things like high fructose corn syrups. Fruit sugars are a mix of fructose and other sugars like glucose. Second, the amount of total sugar in fruit is very low. While the body lacks the ability to convert large quantities of fructose to muscle glycogen effectively, it would be very difficult to consume enough fructose in the form of fruit to make this happen. Fruit has an important place in a well balanced diet, no matter what your goals are. It's loaded with vitamins and fibre, and it tastes great.