The participants reported typically eating less than 2 cups of fruit per day.

The participants ate the equivalent of either 2 cups or less than a half cup (the control) of fruit per day, with an 8-week washout period. The study provided apples, bananas, grapes, oranges, strawberries, and watermelon.

Flow-mediated dilation (the primary outcome; a measure of endothelial function), did not differ between the conditions, nor did blood pressure, C-reactive protein, fasting glucose, LDL-C, total antioxidant capacity, triglycerides, weight, or performance on 5 cognitive tests.

However, fasting insulin and HOMA-IR decreased (improved) with the lower amount of fruit, compared with the higher amount.

Does eating more fruit improve health outcomes? Original paper