Stefani Sassos, MS, RD, a registered dietitian within the Good Housekeeping Institute, explains that excessive sugar can spike your blood sugar levels... and then turn into a sudden drop off afterwards. This is why you may feel super fatigued in the moment, or push through a huge mood swing, in any given afternoon. Over the long run, however, eating too much sugar can greatly influence your risk for heart disease and type 2 diabetes, chronic dietary inflammation, and severe fatigue, among other physical risks. "There's a ripple effect on your body, as it can get accustomed to lots of sugar," she adds, citing habits like a daily office donut or sugary sweet coffee drink. "Over time, it becomes this difficult thing to decipher: Am I addicted to this, did I train my body to crave this food?"