Health column

If the fasting glucose box on your health check results shows 5.6–6.9 mmol/L (100–125 mg/dL), that is impaired fasting glucose, which means prediabetes. It is not diabetes, but it is not normal either. According to the Korean Diabetes Association, 4 in 10 adults aged 30 and older in Korea are in this grey zone.

The week you get your results: confirm the exact numbers

• Think back on whether you fasted for at least 8 hours before the test. If you did not fast long enough, the value can come out high.
• If you have an HbA1c result, look at it too. 5.7–6.4% is also a prediabetes criterion.
• Look at waist circumference, blood pressure, triglycerides and HDL cholesterol as well. If several items are borderline together, also check your metabolic syndrome risk.

Within a month: talk with a medical institution

Rather than judging by a single fasting glucose value, it is better to have a medical institution check, through an HbA1c test or an oral glucose tolerance test, how well your body handles glucose after meals as well. Some people have normal fasting glucose but high blood glucose 2 hours after a meal (impaired glucose tolerance), and the reverse also happens.

For three months: change your routine

• Weight — If you have prediabetes and a BMI of 23 or higher, the Korea Disease Control and Prevention Agency (KDCA) recommends losing and maintaining 5–10% of your body weight.
• Exercise — At least 150 minutes of aerobic exercise a week and muscle-strengthening exercise 2–3 times a week.
• Diet — Cut back on sweet drinks and refined carbohydrates and eat more dietary fibre. The relationship between post-meal blood glucose and dietary fibre is laid out, with the evidence, in the resistant maltodextrin section.

Because HbA1c reflects your average blood glucose over the past 2–3 months, you can see the change by testing again about three months after you change your routine.

After one year: measure again

Prediabetes should be tracked with a test every year. You can compare results only if they are measured under the same conditions (fasting time).