Neurologist says ‘your sugar is normal’ is one of the ‘most misleading statements in medicine’: diabetologist weighs in

Neurologist says ‘your sugar is normal’ is one of the ‘most misleading statements in medicine’: diabetologist weighs in

Dr Sudhir Kumar, a neurologist at Apollo Hospitals, Hyderabad, recently noted in a X post that the statement “your sugar is normal” is one of the most misleading in medicine, citing a case study. “A 48-year-old patient presented with burning feet for 6 months, which worsened at night. He was evaluated by multiple doctors and given a diagnosis of ‘Idiopathic peripheral neuropathy’. His fasting glucose was 94 mg/dL, so diabetes was ‘ruled out’. He was referred to me for further evaluation. HbA1c was 7.1 per cent. So, the real diagnosis was diabetic neuropathy,” he said.

According to Dr Kumar, the problem is “over-relying on fasting glucose”. “Fasting sugar is just a snapshot. Post-meal spikes do the early damage. HbA1c reveals what fasting sugar hides. Many patients already have nerve damage and/or vascular damage …while fasting sugar is still “normal”.

Stressing that the clinical takeaway from such cases is that if you see patients with unexplained neuropathy or idiopathic symptoms, don’t rely on one number (FBS); “check HbA1c and post-meal blood sugars as well.”

“Controversial but true: Fasting glucose is the least sensitive test for early diabetes. By the time fasting sugar rises, the damage has often already begun,” Dr Kumar said.

To verify, we reached out to Dr Pranav Ghody, a consultant endocrinologist and diabetologist at Wockhardt Hospitals, Mumbai Central, who said that fasting blood sugar reflects the glucose level at a single point in time, usually after several hours without food. “It does not reflect how the body manages sugar throughout the day. A person may have normal fasting levels but still experience high spikes after meals. These repeated spikes can silently harm blood vessels and nerves over time, even before fasting levels start to rise. This is why depending on just one reading can sometimes create a false sense of reassurance,” said Dr Ghody.

How do post-meal sugar spikes and HbA1c reveal what fasting sugar may miss?

Post-meal blood sugar levels show how the body reacts after eating, when early imbalances often appear. “HbA1c reflects the average blood sugar levels over the past two to three months. Together, these tests provide a fuller picture. Someone may have a normal fasting reading but an elevated HbA1c, indicating that sugar levels have been higher than expected over time.”

Can nerve damage start even when fasting sugar is normal?

Yes, this can occur, concurred Dr Ghody. “Symptoms like burning sensations in the feet, tingling, or numbness may start even when fasting sugar looks normal. This happens because long-term exposure to fluctuating blood sugar levels can affect nerves and small blood vessels. By the time fasting sugar rises, some damage may have already begun.”

What should people keep in mind if they have unexplained symptoms?

If symptoms like persistent tingling, fatigue, or unusual discomfort are present, it is important not to rely on a single test.

“Examining a mix of fasting sugar, post-meal levels, and HbA1c offers a clearer understanding. Early detection helps in managing the condition better and preventing further complications,” said Dr Ghody.

DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.