A new Harvard University study has found that eating French fries just three times a week could raise the risk of type 2 diabetes by 20%, while other forms of potatoes like boiled, baked, or mashed, carry no such danger. The research, published in the British Medical Journal, examined over 30 years of data from more than 250,000 people.
Lead author Dr. Syed Muhammad Mousavi, along with well-known nutritionist Dr. Walter Willett, said the main issue lies in how potatoes are cooked. Frying at high temperatures in unhealthy oils creates harmful compounds, while boiling or baking keeps their nutritional value without adding trans fats.
The study showed that replacing French fries with whole grains can lower diabetes risk by up to 19%. However, swapping them for another fried food offers no benefit. Experts also warn that fried foods, especially fries, often contain trans fats that increase the risk of heart disease and stroke. Many fries are also coated with flour or breading, raising their carbohydrate content.
Nutritionists stress that potatoes themselves are not the problem. Some studies suggest boiled potatoes may even help with weight loss and lower diabetes risk, with research from Iran, Finland, and the Netherlands showing more than 50% lower risk among people who eat them regularly.
Researchers say the focus should be on healthy cooking methods and better food choices, rather than simply labeling foods as good or bad. The findings, based on two large meta-analyses covering more than 500,000 participants and 43,000 diabetes cases, highlight that how food is prepared can be just as important as what is eaten.
