Higher insulin sensitivity and a lower risk of diabetes was only observed for people who consumed whole fruit, not fruit juice. <...> As well as being high in vitamins and minerals, fruits are a great source of phytochemicals which may increase insulin sensitivity, and fiber which helps regulate the release of sugar into the blood and also helps people feel fuller for longer. Furthermore, most fruits typically have a low glycaemic index, which means the fruit's sugar is digested and absorbed into the body more slowly.
<...>High levels of circulating insulin (hyperinsulinemia) can damage blood vessels and are related not only to diabetes, but also to high blood pressure, obesity, and heart disease.
Dr. Nicola Bondonno, Edith Cowan University, Institute for Nutrition Research