Given that sugar contributes energy (calories), if you consume more than you need you will gain weight. Weight gain increases your risk of getting heart disease, diabetes, high blood pressure or even some types of cancer. However, if you are underweight, sugar can add extra calories so that you can gain weight. If your body doesn't make enough insulin (in case of diabetes), then the sugar you eat increases the sugar in your blood to unhealthy levels.

The body breaks down sugar into the simple sugar that is found in your blood (glucose). Unfortunately, there are no vitamins or minerals in sugar and so it is called an "empty" nutrient. That is why it is the first food to be eliminated from a weight loss diet. By the way, it does not matter if the sugar is white or brown. The amount of molasses in brown sugar is so low it doesn't contribute enough of any vitamin or mineral to count.