He actually goes into the fact that Glucose is necessary.
Sucrose is one part glucose one part fructose.
He argues that historically humans only came into contact with fructose through fruits which naturally contain enough fiber to counteract the affect of the fructose found in the fruit. Now that we refine sucrose and high fructose corn syrup and add it to almost all of our food, and have cut back on our fiber intake due to the way we process our food, we are ingesting more than our bodies can deal with. Thus causing many metabolic problems, Obesity, Diabetes, and Hypertension.
In many ways it is a drug as it has various detrimental affects on the human body.