A doctor explains the health impacts of excessive added sugar intake, including weight gain, increased risk of type 2 diabetes, heart disease, and certain cancers. High sugar consumption also affects oral health and can lead to energy fluctuations, mood changes, and increased risks of depression and anxiety. Quitting added sugar for 14 days can lead to recalibrated reward signals, reduced cravings, stabilized energy, improved insulin levels, and less bloating, though initial symptoms may include headaches or fatigue.