French fries may increase the risk of getting type 2 diabetes, says a very fascinating study.
A large study published in The BMJ found that people who regularly ate French fries had a noticeably higher risk of developing type 2 diabetes.
Meanwhile, potatoes prepared in other ways — such as baking, boiling, or mashing — did not show the same strong association.
Could the type 2 diabetes link be explained away simply in that those who eat a lot of fries are also more likely to overeat ultra-processed foods such as Twinkies, boxed dinner mixes, white bread, donuts, cheese puffs and sugary soda?
Let’s find out some more.
Researchers also discovered that the foods chosen to replace potatoes can influence diabetes risk as well.
Potato Prep
Potatoes contain several beneficial nutrients, including fiber, vitamin C, potassium, and magnesium.
However, they are also rich in starch and can cause blood sugar levels to rise relatively quickly.
Past studies have often linked potato consumption to an increased risk of type 2 diabetes, but many failed to distinguish between different cooking methods.
The new research set out to answer a more specific question: Do French fries affect health differently than other potato dishes?
Scientists also wanted to know whether replacing potatoes with foods like whole grains or rice would change the results.
Study Followed More than 200,000 Adults
The findings were based on data collected from more than 205,000 healthcare professionals in the U.S.
Participants were enrolled in three major long-term health studies and were tracked between 1984 and 2021.
At the beginning of the research, none of the participants had diabetes, cardiovascular disease, or cancer.
Every few years, volunteers completed detailed dietary surveys that allowed researchers to monitor changes in eating habits over time.
During the nearly four-decade follow-up period, more than 22,000 participants developed type 2 diabetes.
French Fries Showed the Strongest Link
After adjusting for lifestyle factors and other dietary influences, researchers found that overall potato consumption was associated with a modest increase in diabetes risk.
But the study did not adjust for what was added into various types of potato dishes. For instance, many people who have a baked potato will add butter or cheese.
For every three servings of potatoes consumed per week, the rate of type 2 diabetes increased by about 5%.
French fries stood out as the biggest concern. Eating three servings of fries per week was associated with a 20% higher rate of type 2 diabetes.
By comparison, consuming the same amount of baked, boiled, or mashed potatoes was not linked to a statistically significant increase in risk.
Whole Grains Were the Better Swap
The study also examined what happened when participants replaced potatoes with other carbohydrate-rich foods.
The strongest results favored whole grains.
Replacing three weekly servings of potatoes with whole grains was associated with an 8% lower rate of type 2 diabetes.
The benefit was even more noticeable when French fries were replaced with whole grains, resulting in a 19% lower diabetes rate.
Researchers say these findings support existing dietary recommendations that encourage greater consumption of whole grains as part of a healthy eating pattern.
White Rice Produced Different Results
When potatoes were replaced with white rice, researchers observed a higher rate of type 2 diabetes.
This increase was seen both for total potato consumption and for baked, boiled, or mashed potatoes.
The findings suggest that replacing one carbohydrate source with another doesn’t automatically improve health outcomes.
Understanding the Study’s Limitations
Researchers caution that the study was observational, meaning it can identify associations but cannot prove cause and effect.
Again, perhaps those who eat a lot of fries are also more likely to lead a sedentary life or be obese.
So it’s clearly possible that other unmeasured factors contributed to the results.
Nevertheless, the research concluded that diabetes risk appears to depend not only on how much potato people eat, but also on how the potatoes are prepared and what foods replace them.
