Adding a little more fruit and veggies to your diet helps a lot if you’re eating little now — but adding even more beyond that doesn’t help as much.

People who eat at least five servings of fruits and vegetables a day — as estimated by blood tests — have about a one-third lower risk of developing type 2 diabetes than those who eat less.

Blood tests for fruit and vegetable nutrients are better at predicting diabetes risk than asking people what they ate, because people often misremember or misreport their diet.

The benefit of eating more fruits and vegetables for preventing diabetes is less strong in older people than in younger ones, possibly because aging changes how the body responds to nutrients.

Even after accounting for body weight, people who eat more fruits and vegetables still have a lower risk of type 2 diabetes, meaning the benefit isn’t just because they’re thinner.

People with the highest levels of fruit and vegetable biomarkers in their blood are about half as likely to develop type 2 diabetes as those with the lowest levels.