Flour is widely cited as a staple carbohydrate that individuals with diabetes should strictly limit, while fruit is often viewed as a cornerstone of a healthy diet. However, one medical expert argues that for diabetic patients, fruit may actually pose a greater health risk than refined flour.
Appearing on the YouTube channel Knowledge Forum Guest Talk, Prof. Lee Seung-hoon of the Department of Neurology at Seoul National University Hospital highlighted the hidden metabolic risks associated with fructose consumption in people with diabetes.
“If you ask which is worse for a person with diabetes—eating flour or eating fruit—fruit is worse,” Lee said.
The Metabolic Trap: Glucose vs. Fructose
Lee explained that most flour is broken down into glucose, an energy source distributed throughout the body and utilized by nearly every cell, including muscle and brain tissue. In contrast, fruit consists of roughly equal parts glucose and fructose—and fructose can only be processed by the liver.
Portion control presents another major challenge. “In many cases, it is difficult to stop after eating just one piece of fruit,” Lee noted. “You try to eat a single tangerine, but you end up reaching for more. That is a form of addiction.” As a result, individuals frequently consume large quantities of sugar without realizing it.
When excess fructose is ingested, it rapidly accumulates as abdominal visceral fat and liver fat. “The liver converts fructose into lactate, which can be utilized as energy during exercise,” Lee explained. “However, when you are sedentary, the remaining fructose is converted into fat at a very rapid rate.”
Lee linked this process to high-fructose corn syrup (HFCS), a sweetener containing roughly 55% fructose that was introduced by the U.S. beverage industry to cut manufacturing costs. Today, HFCS-sweetened drinks are recognized as a major driver of global obesity. In effect, consuming excessive amounts of fruit under the assumption that it is healthy can yield physiological results similar to drinking soda.
Still, Lee clarified that he does not dismiss fruit's overall nutritional value. “When people say fruit is good for you, it is not because of the sugar—it is because of the rich concentration of micronutrients, minerals, and vitamins,” Lee said. “However, the fructose that provides its sweetness is not beneficial for your health.”
Achieving Remission: Can Diabetes Be Reversed?
Addressing whether diabetes can be cured, Lee explained that patients can achieve clinical remission—recovering and maintaining normal blood sugar levels—through strict management.
“If you maintain rigorous control, you can live out your life in a state that effectively reverses diabetes,” Lee said. “For instance, when I advise patients with a glycated hemoglobin (HbA1c) level of 7.3% to manage their diet and exercise, about 30% to 40% return to normal levels.”
He cited an extreme case: “One patient presented with an HbA1c in the 9% range—a level severe enough to consider a diabetic emergency. Yet, within just six months of lifestyle modification, their blood sugar dropped to normal levels and remained stable for several years.”
Essential Lifestyle Habits for Blood Sugar Management
Effective diabetes management hinges on consistent blood sugar control through daily habits. Maintaining regular meal times and eliminating snacks are essential for avoiding glucose spikes. Additionally, taking a 15-minute walk following meals significantly aids postprandial blood sugar regulation.
Dietary balance plays an equally critical role. Reducing rapidly absorbed carbohydrates while prioritizing vegetables and lean protein helps stabilize blood glucose levels. Regarding dietary fats, experts recommend limiting saturated fats in favor of higher-quality options such as olive oil. Because obesity remains a primary risk factor for diabetes, long-term weight management remains paramount.
