Ah, food studies. The breeding ground of bad science. I am not saying this is bad science, but a quick glance shows this to be survey data.

The problem with the data is that people who eat "healthy" probably care more about their health. Even if the food has a negative effect, they could have other tendencies (exercise) that outweigh any negatives.

Plus they probably eat more carefully, in general, drink less, etc. So... correlation != causation yada yada

A better study would be to take unhealthy people and now introduce the fruits and veg and see what happens.