The World Health Organization suggests that no more than 10 percent of your total daily calories come from added sugar. The American Heart Association recommends that women eat less than six teaspoons of added sugar every day, and that men should not eat more than nine teaspoons of added sugar. That's about 100 and 150 calories for women and men, respectively.
The discretionary calorie allowance is small -- maybe only half of a candy bar, one can of soda, or a small scoop of ice cream -- and you don't get separate accounts for other types of foods like greasy chips or alcohol. Actually, if you eat a high-fat steak for dinner, you'll probably use those discretionary calories with the extra fat before you get to dessert.
If you divide your discretionary calorie budget by the number of calories per gram of sugar, you'll know how many grams of sugar you can have and still stay within your overall calorie limits. If you allow yourself 200 calories per day for treats, that would equal 50 grams of sugar (here's how you convert grams of sugar to teaspoons). I think it's important know that many sugary treats also contain some amount of fat, which needs to be included in the discretionary calorie total as well. One gram of fat has nine calories.
Many of us love sweetened foods, but the extra calories can be a problem. That's because added sugars don't add anything but empty calories, meaning there's no extra nutritional benefit. It's not easy to avoid added sugars completely, but fortunately, it's not really necessary to abandon your sweets completely. Choose your sweet treats wisely and keep them small so the additional calories remain within in your daily calorie budget.
American Heart Association. Carbohydrates and Sugars. Accessed April 20, 2010. http://www.americanheart.org/presenter.jhtml?identifier=4471
United States Department of Agriculture. "Discretionary Calories." Accessed May 9, 2011. http://www.mypyramid.gov/pyramid/discretionary_calories.html.