A one-hour glucose reading above 155 mg/dL may reveal impaired insulin sensitivity and rising cardiometabolic risk even when fasting results appear normal, experts say.
Normal fasting blood sugar does not necessarily mean the body is handling glucose well, according to Taiwanese cardiologist Tseng Kuo-hsiang, who has highlighted evidence that a sharp rise in blood sugar one hour after a glucose load can signal earlier metabolic trouble. In a post on his Facebook page, Tseng cited research suggesting that a one-hour post-load glucose reading above 155 mg/dL may point to reduced insulin sensitivity and weakening pancreatic beta-cell function, even when later measurements return to a normal range.
The concern is that people can appear to pass conventional screening while still carrying a higher risk of type 2 diabetes and cardiovascular disease. Studies indexed in PubMed and published in journals including the Journal of Clinical Endocrinology & Metabolism, Diabetologia and Hypertension have linked one-hour post-load glucose at or above 155 mg/dL with a poorer cardiometabolic profile, greater arterial stiffness, higher inflammatory markers and signs of subclinical organ damage. In some groups, the combination of elevated one-hour glucose and an HbA1c result of 5.7% or above was associated with an even less favourable risk pattern.
Tseng said the practical lesson is that screening should not stop at fasting glucose alone. For people with obesity or a family history of diabetes, he urged attention to HbA1c as well as routine glucose checks, especially if they often feel unusually sleepy or drained after meals. That, he said, may be a clue that blood sugar is surging soon after eating rather than being controlled efficiently.
He also recommended dietary changes aimed at slowing glucose absorption. Replacing white rice, noodles and white bread with brown rice, oats and sweet potatoes, and adding more vegetables rich in soluble fibre, may help flatten post-meal spikes. However, evidence on low-glycaemic index diets is not entirely settled: the American Medical Association has noted that one JAMA study found such diets did not improve cardiovascular risk factors in overweight and obese patients with raised blood pressure, while a Cochrane review concluded there was not enough trial evidence to recommend low-glycaemic index diets specifically for improving cholesterol, blood pressure or cardiovascular events.
Tseng’s final piece of advice was movement after eating. A 15- to 30-minute walk after meals, he said, can help muscles use circulating glucose and may be a simple way to blunt post-prandial rises. His broader message is that metabolic health cannot be judged from a single figure; instead, fasting glucose, HbA1c, post-meal patterns and everyday habits should be considered together, particularly in people already at higher risk.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
