Let me start from the basics for those who might not be familiar with things.
Carbohydrates are the primary source of energy for our body. Sugars are simple carbohydrates which can be absorbed by our body very easily. Now that explains our instinct to sweet tooth. We have our sweet affinity to sweets LOL.

Learning NO 1:Not all sugars function equal
Glucose – the best source of sugar that we can absorb. Our body converts carbohydrates to glucose in order to utilize as energy.Fructose – The common sugar found in corn and fruits. Better utilized by liver than muscle cells.

Sucrose – Also known as table sugar. Unlike the other two types of sugar, it is the combination of both. A molecule of sucrose contains a molecule of glucose and a molecule of fructose.

Learning NO 2: Fructose can lay down the highway of obesity
Fructose is a sugar just like glucose, but the way it metabolizes in our body makes all the difference in the world and affects the metabolism and health.While all cells use some energy in the process of metabolizing food, whether it’s fat or sugar,But Fructose leaves your cells completely depleted. AS a result, the cells do not function normally and gives back an inflammatory response. This state of cells is called as oxidative stress.
Researchers found that when the energy is depleted… the ATP levels fell (ATP is our energy source). The ATP that had been consumed. When all the ATP is depleted, a substance called as uric acid is formed on your cell. Uric acid is known to cause gout and has been long associated with obesity too. Dr Jhones was able to demonstrate that “uric acid can actually stimulate fat accumulation in cells through this process of working on the mitochondria where the ATP is made,”

Summary of our learning:

Fructose containing foods make you fat not by calories but by depleting ATP from cells and generating uric acid in the cells.When your goal is to lose FAT or getting fitter, Keep your fruit intake to minimum