I always assumed it would be the opposite: something that a lot of people already recognize as being dangerous, but which lacked concrete evidence demonstrating how dangerous it is. So my candidates for a future "omg we have to stop this" are:

- bad posture at office jobs (probably mandated adjustable standing desks in the future)

- stress from a long, high-traffic commute

- insufficient sleep

- per the article, high-sugar foods. EDIT: technically, a high-sugar diet. Part of the problem is that no one unit of sugar by itself is the problem, so you can't point to any one food as the culprit.