One number is not the whole pattern
Home meters are useful but technique, strips, hand contamination and timing affect readings. A clinician looks for a pattern across fasting, after-meal and bedtime readings, along with HbA1c and symptoms.
Common reasons glucose rises
Missed medicine, infection, steroid treatment, dehydration, stress, poor sleep, a change in food or activity, and progression of diabetes can all contribute. Finding the reason is more useful than blaming one food.
Prepare for a useful review
Bring your meter or log, current medicines with doses, recent HbA1c, kidney and liver reports, and details of recent illness. This makes treatment changes safer and more precise.
Frequently asked questions
Is sugar 300 always an emergency?
It is significantly high and should not be ignored. Urgency depends on symptoms, ketones, hydration, pregnancy, diabetes type and whether it stays high.
Should I walk to lower a very high reading?
Not automatically. Exercise can be unsafe when you are unwell or ketones are present. Ask your clinician for a personal sick-day plan.
Guidelines and references
Dr. Pratyush Kumar · DNB Family Medicine, Sir Ganga Ram Hospital · DFID Diabetes Fellowship, Christian Medical College, Vellore
Updated and medically reviewed October 2026 · General education, not an individual prescription.