Researchers in Denmark randomized 63 patients to high fruit or low fruit intake, and after 12 weeks, the 2 groups had similar drops in glycated hemoglobin (HbA1c) levels, weight, and girth. They enrolled patients with newly diagnosed type 2 diabetes who had been referred for nutritional counseling. The patients were an even mix of men and women, with a mean age of 58 years and a mean body mass index (BMI) of 32.  

Allan S. Christensen, the lead of the research group: 

We conclude that advice to restrict fruit intake as part of standard [medical nutrition therapy] in overweight adults with newly diagnosed type 2 diabetes mellitus does not improve glycemic control, body weight, or waist circumference.

The 32 subjects in the low-fruit-intake group were advised eat no more than 2 pieces of fruit a day, whereas the 31 subjects in the high-fruit-intake group were told to indulge in 2 or more pieces of fruit a day.

A piece of fruit was defined as the amount that contained about 10 g of carbohydrate - for example, an apple (100 g), half a banana (50 g), or an orange (125 g). The subjects were also instructed to eat whole fruit, skip dried fruit, and not drink fruit juice.

Over the 12 weeks, on average, fruit consumption rose from 194 g/day to 319 g/day in the high-intake group and decreased from 186 g/day to 135 g/day in the low-intake group.

Patients in the high-fruit-intake group had a significant drop in HbAIC levels, from 6.74% to 6.26%. They also lost about 2 kg (from 92 kg to 90 kg) and trimmed their waist by about 4 cm (from 103 to 99 cm). Similar results were obtained by patients in the low-fruit-intake group, and there were no significant between-group differences in these 3 outcomes.