A good substitution for sugar in a recipe is agave nectar. Use 2/3 cup of agave nectar for every 1 cup of sugar called for in a recipe.
Another good substitute for sugar in a recipe is honey. Use 3/4 cup for every 1 cup of sugar in the original recipe. Maple sugar can also be used in place of sugar. Measurements are 3/4 cup for every 1 cup of sugar.
Stevia can be used as a sugar replacement. Only 1/2 cup is needed per 1 cup of sugar. One cup of Sucanat, or sugar-cane-natural, can be used in substitution of 1 cup of sugar.