For decades, potatoes have had a mixed reputation regarding health. However, a major new study published in The BMJ reveals that the way potatoes are cooked significantly affects their health effects. Researchers discovered that eating French fries substantially increases the risk of developing type 2 diabetes, while baked, boiled, or mashed potatoes do not carry the same health risks.
The findings arise from an extensive analysis of more than 205,000 health professionals in the United States who were tracked for nearly four decades. During this observational period, over 22,000 participants developed type 2 diabetes, a chronic condition where the body struggles to effectively use insulin and regulate blood sugar levels.
The study found that consuming three servings of French fries per week was associated with a 20 percent increase in the risk of developing the disease. Contrarily, consuming unfried potatoes did not lead to a significant rise in risk.
Researchers also explored dietary substitutions. Replacing French fries with whole grains, such as oats, brown rice, or barley, reduced the risk of diabetes by 19 percent. However, replacing potatoes with white rice actually increased the risk, underscoring the importance of replacement foods for metabolic health.
While potatoes are rich in starch, which breaks down rapidly into glucose, they also provide valuable nutrients such as vitamin C, potassium, magnesium, and dietary fiber. The researchers emphasized that potatoes can remain part of a healthy diet if prepared using healthier cooking methods.
Although this study was observational and cannot definitively prove that French fries directly cause diabetes, its unprecedented scale and the research’s four-decade duration provide concrete evidence.
Eventually, the findings strongly support current dietary guidelines: prioritize whole grains, limit highly processed foods, and choose baked or boiled potatoes over fried options to protect long-term health.