Fructose is half of table sugar and almost everyone in a modern culture eats a lot of it. Every piece of cake, donut, Coke, and candy bar that you ingest pours huge amounts of fructose into your system, causing a cascade of nasty chemical, hormonal and metabolic responses. One researcher nicely summarized the perils by stating that "Fructose elevates triglycerides, cholesterol, uric acid, urea nitrogen and carnitine in blood [and] decreases glucose tolerance, increases insulin resistance and causes a shift in balance from oxidation to esterification of nonesterified fatty acids, resulting in elevated secretion of VLDL". 
Ouch! Short of kidnapping your family and torching your house, what worse things could something do to you? Look at that list: fructose raises most of the major markers for heart disease. Other studies have shown that fructose leads to atherosclerosis, which will be very bad for your penis. 
Every male should understand what makes fructose unique and why it is one of the worst foods for our sex lives:
1) J of Nutr, Sep 1998, 128(9):1442-1449, "Long-Term Fructose Consumption Accelerates Glycation and Several Age-Related Variables in Male Rats", Boaz Levi and Moshe J. Werman
2) J Atheroscler Thromb, 2005, 12(5):260-267, "Fructose Ingestion Enhances Atherosclerosis and Deposition of Advanced Glycated End-products in Cholesterol-fed Rabbits"