Added sugar damages our liver, messes up our metabolism, impairs brain function, and causes wrinkles.
It is the type of sugar that is added to processed foods and drinks to improve the flavor, texture or color of a food or drink. Added sugar and natural sugars are very different. According to University of Vermont professor Rachel K. Johnson, "It's almost impossible to over consume fructose by eating too much fruit." For instance, you would need to eat 6 cups of strawberries to consume the same amount of fructose as in one can of Coke.
This type of sugar provides little to no nutritional value. It does, however, provide an excessive amount of calories. The average American consumes about 32 teaspoons of added sugar every day. Eight of those teaspoons are from high-fructose corn syrup. Those 32 teaspoons of sugar add up to 27 pounds each year.
Glucose and fructose are the two molecules that make up sugar. Every cell in the body can metabolize glucose, and our bodies will make it if we don't consume it. Only the liver can metabolize fructose. The liver turns fructose into glycogen, the stored form of glucose in the liver. When the liver has stored the maximum amount of glycogen possible, the excess fructose gets turned into fat.
In terms of what kind of fat, over consuming added sugar increases your level of triglycerides. Triglycerides are a type of fat found in your bloodstream. Having too many triglycerides raises your risk of developing certain diseases, such as cardiovascular disease and coronary artery disease. Your liver becomes resistant to insulin, which in turn causes obesity, metabolic syndrome, and other diseases.
Overeating sugar can also make our skin dull and cause wrinkles due to a process called glycation. Glycation is the process in which sugar in your bloodstream attaches to proteins to form advanced glycation end products (AGEs). AGEs are harmful molecules that accumulate and damage adjacent proteins (like a domino-effect). Collagen and elastin are both vulnerable to AGEs.
Now that you understand (or have been reminded) of some of the harmful effects sugar has on the body, you might want to cut back. Consider buying foods that are "unsweetened" or have "no added sugar." Try drinking only water. Ultimately, it's up to you to be aware of what's in the food you're eating.