HFCS has the exact same sweetness and taste as an equal amount of sucrose from cane or beet sugar but it is obviously much more complicated to make, involving vats of murky fermenting liquid, fungus and chemical tweaking, all of which take place in one of 16 chemical plants located in the Corn Belt. Yet in spite of all the special enzymes required, HFCS is actually cheaper than sugar. It is also very easy to transport–it’s just piped into tanker trucks. This translates into lower costs and higher profits for food producers.
The development of the HFCS process came at an opportune time for corn growers. Refinements of the partial hydrogenation process had made it possible to get better shortenings and margarines out of soybeans than corn. HFCS took up the slack as demand for corn oil margarine declined. Lysine, an amino acid, can be produced from the corn residue after the glucose is removed. This is the modus operandi of the food conglomerates–break down commodities into their basic components and then put them back together again as processed food.
Wikipedia’s entry for High fructose corn syrup.
A list of foods containing hfcs.