Eating chips three times a week raises type 2 diabetes risk by 20%, study finds

From theguardian.com

Baking, boiling or mashing potatoes raises risk by 5% and replacing with whole grains lowers risk significantly 

Love potatoes? Well, there’s good news and there’s bad news.

Eating chips frequently has been linked to a higher risk of developing type 2 diabetes compared with baking, boiling or mashing the tuber.

Consuming french fries three times a week increases the chances of someone getting the disease by 20% – and doing so five times a week by 27% – according to a study published in the British Medical Journal.

Globally, potatoes are the third most commonly consumed food crop, after rice and wheat.

Nine out of 10 of the estimated 5.8 million people in the UK with diabetes have the type 2 version of the disease, which is closely associated with lifestyle, especially diet.

The findings confirm potatoes do not of themselves pose a danger to health, but frying them to turn them into chips, and eating them regularly, does make a diagnosis of type 2 diabetes more likely.

An international team of researchers, led by Seyed Mohammad Mousavi, a public health expert at Harvard University, investigated the relationship between potato intake and the risk of developing type 2 diabetes. They based their findings on food questionnaires filled out by 205,000 health professionals in the US every four years between 1984 and 2021.

Someone who eats chips three times a week was found to raise their risk of diabetes by 20%, but those who ate potatoes with the same regularity after baking, boiling or mashing them did so by only 5%.

“The high starch content of potatoes, leading to a high glycaemic index and load, combined with possible loss of nutrients and possible health risks resulting from various cooking methods, could contribute to adverse health outcomes,” the study explains.

Eating chips five times a week was associated with an even greater risk – 27% – of developing type 2 diabetes. Photograph: Sally Anscombe/Getty Images

Replacing potatoes with whole grains lowers the risk of diabetes by 8%, and if grains are eaten instead of chips specifically, that cuts the risk by 19%. Dr Kawther Hashem, a lecturer in public health nutrition at Queen Mary University of London, said: “Potatoes can be part of a healthy diet, but it’s how we prepare them that makes the difference. Boiled, baked or mashed potatoes are naturally low in fat and a source of fibre, vitamin C and potassium.

“But when we deep fry them into chips or french fries, especially in large portions and with added salt, they become less healthy with their high-fat, salt and calorie content that’s much more likely to contribute to weight gain and increase the risk of type 2 diabetes.”

However, replacing any form of potatoes with white rice is a bad idea as it leads to an increased risk of type 2 diabetes, the paper found. Dr Hashem added: “This research reinforces the simple message, which is to enjoy potatoes – just don’t rely on chips as your go-to option. And, where possible, try swapping them out for whole grains like brown rice, bulgur wheat, wholemeal pasta or even sweet potato with skin on, which are healthier and protective for long-term health.”

The researchers stressed their findings were observational and did not prove a cause and effect relationship between eating chips and type 2 diabetes risk.

The Food Standards Agency and Department of Health and Social Care both declined to comment.

https://www.theguardian.com/food/2025/aug/06/eating-chips-regularly-raises-risk-of-type-2-diabetes-by-20-study-finds