The body uses sugars and starches from carbohydrates to supply glucose to the brain and provide energy to cells around the body. Carbohydrates also provide fiber and other nutrients to the body. Our bodies need one type of sugar, called glucose, to survive. Glucose is the number one food for the brain, and it's an extremely important source of fuel throughout the body,â?? says Dr. Kristina Rother, an NIH pediatrician and expert on sweeteners. The AHA suggests a stricter added-sugar limit of no more than 100 calories per day (about 6 teaspoons or 24 grams) for most adult women and no more than 150 calories per day.