Actually, high fructose corn syrup is a combination of fructose and glucose - the same sugars in most fruits.
For example, grapes are 52% fructose, 46% glucose, and 1% sucrose. Pears are 63% fructose, 29% glucose, and 8% sucrose. High fructose corn syrup used in sodas is usually 55% fructose and 42% glucose.
The "natural" sugar you're thinking of is sucrose. Sucrose is not the dominant sugar found in fruit. Fructose and glucose are the predominant sugars found in fruits and in high fructose corn syrup.
For example, grapes are 52% fructose, 46% glucose, and 1% sucrose. Pears are 63% fructose, 29% glucose, and 8% sucrose. High fructose corn syrup used in sodas is usually 55% fructose and 42% glucose.
The "natural" sugar you're thinking of is sucrose. Sucrose is not the dominant sugar found in fruit. Fructose and glucose are the predominant sugars found in fruits and in high fructose corn syrup.