I'm not sure this can be much clearer:
"For a while the association between sugar consumption and type 2 diabetes was thought to solely relate to weight gain, but new research conducted at UC San Francisco indicates that sugar intake may also be directly linked to diabetes."
"As far as I know, this is the first paper that has had data on the relationship of sugar consumption to diabetes. This has been a source of controversy forever. It's been very, very difficult to separate sugar from the calories it provides. This work is carefully done, it's interesting and it deserves attention."
Here's more on the study:
Quantity of sugar in food supply linked to diabetes rates, researcher says
https://med.stanford.edu/news/all-news/2013/02/quantity-of-s...
"Does eating too much sugar cause diabetes? For years, scientists have said 'not exactly.' Eating too much of any food, including sugar, can cause you to gain weight; it’s the resulting obesity that predisposes people to diabetes, according to the prevailing theory.
"But now the results of a large epidemiological study suggest sugar may also have a direct, independent link to diabetes. Researchers from the Stanford University School of Medicine, the University of California-Berkeley and the University of California-San Francisco examined data on sugar availability and diabetes rates from 175 countries over the past decade. After accounting for obesity and a large array of other factors, the researchers found that increased sugar in a population’s food supply was linked to higher diabetes rates, independent of obesity rates. Their study was published Feb. 27 in PLOS ONE."