French fries linked to higher diabetes risk; nonfried potatoes not

A large, long-term analysis of diet and health found that how potatoes are prepared appears to matter as much as how often they are eaten. Researchers followed more than 200,000 U.S. adults for up to 36 years and found that three weekly servings of French fries were associated with about a 20 percent higher risk of developing type 2 diabetes, while the same amount of potatoes prepared by boiling, baking, or mashing showed no significant increase in risk. The study also suggested that swapping potatoes for whole grains could meaningfully lower diabetes risk, with a larger benefit seen for replacing French fries than for nonfried potatoes.

The investigation drew on three ongoing, long-running health programs in which participants regularly reported their diets and health status. Over the observation period, more than 22,000 participants developed type 2 diabetes. After controlling for age, weight, lifestyle, and overall diet, the researchers found a clear pattern: the method of preparation changed the health impact of potatoes. Three extra weekly servings of total potatoes were linked to a modest rise in diabetes risk, but the effect was much more pronounced for French fries....