Of course, a number of individual factors can also play a role in whether it's appropriate to exercise while fasting, such as your age, when you last ate, whether or not you're pregnant, taking medications, your medical history, level of fitness, and the type of workout you engage in.
Children should consume no more than 12 grams (92 calories) or 3 teaspoons of added sugar per day, according to the American Heart Association. Teens should consumer no more than 18-37 grams (138-285 calories) or 5 teaspoons of added sugar each day.
Too much sugar is bad for health, but how much is too much? The accepted guideline is that added sugars should not make up more than 10 percent of your total energy intake for the day, although, many nutritionists will recommend even less than this. How much is 10 percent? Well, in a 2000-calorie-a-day diet, 10 percent would be equal to about 50 grams, or 10 teaspoons of sugar. Unfortunately, most Americans consume 30 to 40 teaspoons or more of refined sugar per day. Most of this sugar comes from food products to which sugar has been added, such as soda, candy and baked goods. A can of soda alone can contain around 10 teaspoons of added sugar!