Palpitations are often caused by consumption of caffeine, alcohol, and decongestants. Tobacco use can also cause palpitations. Sugar consumption in most people does not cause palpitations. However, if a person has low blood sugar episodes, consumption of too much simple sugar can cause a strong insulin (insulin helps move glucose into cells to be used for energy) response and drop the blood sugar too rapidly. This results in a reaction of the body similar to stress. The heart rate will increase, the person will be shaky, clammy and feel faint.
Diabetics have also reported palpitations if their blood sugar is too high.