While many people are careful with obvious sweets, some "healthy" snacks and common daily habits can trigger surprising spikes in blood sugar. Cho Young-min, a professor in the Division of Endocrinology and Metabolism at Seoul National University Hospital, recently highlighted several "blood sugar bombs" that even medical professionals find shocking.
Appearing on the KBS program Secrets of Birth, Aging, Illness, and Death, Professor Cho shared his own experience: "There are foods I thought would be fine, but my blood sugar went up surprisingly high. I was shocked." He specifically identified dried fruit, sweet potatoes, and unsweetened juice as primary culprits.
The Concentrated Sugar in Healthy Snacks
Professor Cho noted that the form of food significantly impacts consumption volume. "With a ripe persimmon, you usually eat one and stop, but with dried persimmons, you can easily eat two to five at once," he explained. Because the sugar from the original fruit is concentrated during the drying process, these snacks act as a dense source of glucose. Similarly, he warned that sweet potatoes contain high amounts of sugar and are often consumed in quantities larger than recommended for stable blood sugar management.
The term "unsweetened" can also be misleading. Unsweetened juice simply means no additional sugar was added during manufacturing; it does not mean the drink is sugar-free. "Through selective breeding, fruit itself has become much sweeter than in the past," Cho said, noting that some scholars now refer to fruit as "dessert that grows on trees."
He further emphasized that eating whole fruit is fundamentally different from drinking juice. In juice form, essential nutrients like dietary fiber are often removed, leading to a much more rapid absorption of sugar into the bloodstream.
The Instant Mix Coffee Habit
The most common blood sugar bomb seen in clinical practice, according to Professor Cho, is instant mix coffee. While one packet a day may not be detrimental, the frequency of consumption is the real danger.
"I see many patients who drink three, four, or even five to six cups a day," Cho said. A single stick of instant mix coffee contains approximately 5–7g of sugar along with fat from the creamer, making it high in both calories and sugar. He observed that many patients see significant improvements in their blood sugar levels simply by cutting back on these mixes. He recommends switching to black coffee or unsweetened teas, such as green or black tea.
Habitual Consumption and Metabolic Risk
Research suggests that plain coffee may actually lower the risk of type 2 diabetes, but those benefits are neutralized when sugar and creamer are added. The sugar in instant mixes causes large fluctuations in blood glucose, which can lead to increased insulin resistance over time.
The primary risk factor is the habitual nature of the habit. Because these drinks are sweet and convenient, they are often consumed repeatedly throughout the day. This accumulated intake of sugar and calories increases body fat and significantly raises the risk of metabolic diseases.
