Researchers have found that intermittent fasting done to lose weight impairs the action of sugar-regulating hormone -- insulin -- which may increase the risk of diabetes.

The findings, presented at the Endocrinology annual meeting, ECE 2018, in Barcelona, suggest that fasting-based diets may be associated with long-term health risks and careful consideration should be made before starting such weight loss programmes. Type-2 diabetes is a growing global epidemic that is often attributed to poor diet and a sedentary lifestyle, so is closely linked to obesity.

Blood sugar is partially regulated by the hormone insulin, which is produced by the pancreas if insulin levels are too low, or the body becomes resistant to its effects. Type-2 diabetes and high blood sugar levels can cause serious health issues, including heart, kidney and eye damage.

"This is the first study to show that, despite weight loss, intermittent fasting diets may actually damage the pancreas and affect insulin function in normal healthy individuals, which could lead to diabetes and serious health issues," said co-author Ana Bonassa from the University of Sao Paulo in Brazil.

For the study, the researchers examined the effects of fasting every other day on the body weight, free radical levels and insulin function of normal, adult rats, over three months. Although the rats' body weight and food intake decreased as expected over the study period, the amount of fat tissue in their abdomen actually increased, the researcher said. The cells of the pancreas that release insulin showed damage, with the presence of increased levels of free radicals and markers of insulin resistance were also detected, the researchers added.