Potatoes have been part of human diets for centuries. They are inexpensive, filling, and widely available.
Around the world, people enjoy potatoes in many forms, from baked potatoes and mashed potatoes to French fries.
Despite their popularity, potatoes have often been blamed for increasing diabetes risk because they contain large amounts of starch.
A major study published in The BMJ suggests that the story may be more complicated.
The research indicates that the risk may depend less on potatoes themselves and more on how they are prepared and what foods replace them in the diet.
Type 2 diabetes affects hundreds of millions of people worldwide. The condition develops when the body can no longer effectively control blood sugar levels. Over time, this can damage blood vessels and organs and increase the risk of serious health problems.
Researchers analyzed health data from more than 205,000 Americans who participated in three large health studies between 1984 and 2021.
None of the participants had diabetes at the beginning of the study. During follow-up, more than 22,000 people developed the disease.
When researchers examined potato consumption, they found that French fries stood out. Eating three servings of French fries each week was associated with a 20% higher rate of type 2 diabetes. By contrast, baked, boiled, and mashed potatoes were not linked to a significant increase in risk.
One possible explanation is that deep frying changes the nutritional profile of potatoes. French fries contain more calories and fat than potatoes prepared in simpler ways. They are also often eaten with other less healthy foods.
The study also explored what happened when potatoes were replaced with different foods. Replacing potatoes with whole grains was associated with a lower risk of diabetes. Whole grains contain fiber and nutrients that help support healthy blood sugar control.
The biggest benefit appeared when French fries were replaced with whole grains. Diabetes risk was substantially lower in this group. Examples of whole grains include oats, barley, brown rice, quinoa, and whole wheat products.
However, replacing potatoes with white rice did not help. In fact, it was linked to a higher risk of diabetes. This finding highlights an important lesson. Nutrition is not only about removing foods from the diet. It is also about choosing healthier alternatives.
The study challenges the idea that all potatoes should be considered unhealthy. Potatoes provide important nutrients and can be part of a balanced diet. The findings suggest that preparation methods are a major factor.
The researchers noted that this was an observational study and therefore cannot prove cause and effect. Still, the long follow-up period and very large participant group provide valuable evidence.
An editorial published alongside the study argued that potatoes should not be treated as a single category. Baked, boiled, and mashed potatoes may fit within a healthy and environmentally sustainable diet, while French fries appear to be a different story.
Overall, the findings support a balanced approach. People do not necessarily need to avoid potatoes altogether. Instead, they may benefit from reducing French fry consumption and choosing more whole grains. This simple change could help lower diabetes risk over time.
From a scientific perspective, the study is important because it looks beyond individual foods and considers dietary patterns and food substitutions.
The results strengthen current dietary recommendations that promote whole grains as part of a healthy diet.
Future studies in more diverse populations will help confirm the findings, but the evidence already suggests that when it comes to diabetes prevention, whole grains are a better choice than French fries.
If you care about diabetes, please read studies about bananas and diabetes, and honey could help control blood sugar.
For more health information, please see recent studies about Vitamin D that may reduce dangerous complications in diabetes and plant-based protein foods may help reverse type 2 diabetes.
Source: Harvard T.H. Chan School of Public Health.
