How potatoes increase the risk of developing diabetes

Potatoes are a versatile foodstuff, but according to research conducted by the Harvard T.H. Chan School of Public Health, not every method of preparing them has the same effect when it comes to the risk of diabetes. The researchers identified a link between the consumption of French fries and a higher risk of developing type 2 diabetes. By contrast, they found no evidence of an increased risk of diabetes with baked, boiled or mashed potatoes.

As part of the study, the team analysed the eating habits of 205,000 adults over a period of several decades. The participants regularly completed questionnaires on their eating habits for approximately 30 years and reported on how their health developed over this time period. Over the course of the research period, 22,299 people developed type 2 diabetes.

The study found that three portions of French fries per week increased the risk of developing type 2 diabetes by 20 per cent. There was no significant correlation found for baked, boiled or mashed potatoes. A potential protective factor also emerged: where baked, boiled or mashed potatoes are replaced by wholemeal products such as wholemeal pasta or wholemeal bread, the risk is reduced by four per cent. According to the results, replacing French fries with wholemeal alternatives reduces the risk by as much as 19 per cent.

“The public health message here is simple and powerful: small changes in our daily diet can have an important impact on risk of type 2 diabetes,” said co-author Walter Willett, professor of epidemiology and nutrition, in a press release. “Limiting potatoes – especially limiting French fries – and choosing healthy, whole grain sources of carbohydrate could help lower the risk of type 2 diabetes across the population.” The findings are also important for policymakers said Willett. “Not all carbs – or even all potatoes – are created equal, and that distinction is crucial when it comes to shaping effective dietary guidelines."