One gram of sugar contains 3.87 calories. While some sugars are good for you, most lead to overeating, which in turn can cause weight gain. Knowing how many calories are in a gram of sugar can help a person better understand information provided on nutrition labels and make different choices.
Women should eat no more than 24 grams of sugar, or 100 calories, and men no more than 36 grams of sugar, or 150 calories, per day, according to the American Health Association. Some fruits, vegetables and dairy products contain simple sugars, which are part of a healthy diet. Other types of food and beverages, such as soda, energy drinks, candy, salad dressings and pasta sauces, contain more complex sugars, which are not part of a healthy diet. To figure out how many sugar calories in a food or beverage, the number of sugar grams, which is the unit of measure on nutrition label, can be multiplied by 3.87.