Counting calories is a weight loss strategy many of us rely upon. Sugar contains 16 calories per teaspoon, a number that can quickly add up throughout the day. As part of our low-calorie diets, some of us use artificial sweeteners as sugar substitutes, since they are either very low or completely lacking in calories. Some of the most popular artificial sweeteners include aspartame (NutraSweet and Equal), saccharin (Sweet n’ Low), and sucralose (Splenda).