Pleasing blood sugar results after changing my breakfast food

by David
(Cambridge, Ely)




By David (Cambridge, Ely)




QUESTION:


I have had type 2 diabetes for 15 years and had no major problems until about a month ago, when my blood sugar rose to 10–15 mmol/L. I increased my tablets, but my morning readings remained high, so I changed breakfast from Weetabix to a boiled egg with brown bread.


Since then, I can go to bed at 6 mmol/L, wake at 5 mmol/L, and still be around 5 mmol/L about 90 minutes after breakfast. My readings also seem similar after other foods. Even ice cream or sugary foods do not appear to make much difference. One morning I was 7 mmol/L, and after going all day without food, I only fell to 4.5 mmol/L.


Why would changing my breakfast produce these results? I am pleased with the improvement but would like to understand it.




Answer by Dr. Albana Greca Sejdini, MD, MMedSc

Medically reviewed by Dr. Ruden Cakoni, MD, Endocrinologist | Last reviewed: July 2026




Quick Answer


David, replacing Weetabix with an egg and a measured portion of bread probably reduced the amount and speed of carbohydrate entering your bloodstream. However, you also increased your diabetes tablets, which may be an equally important reason for the improvement. Do not change the dose without your prescriber. Good readings do not mean diabetes has disappeared or that sugary foods are harmless.




Hi David,



Your current readings are generally reassuring. A level of 5 mmol/L equals about 90 mg/dL, 6 mmol/L about 108 mg/dL, and 4.5 mmol/L about 81 mg/dL. For many nonpregnant adults, common targets are 4.4–7.2 mmol/L before meals and below 10 mmol/L about 1–2 hours after starting a meal, although personal targets vary. See our guide to blood sugar levels by time of day.



Why the New Breakfast May Help



Weetabix and bread both contain carbohydrate, but portion size, processing, fiber, protein, and fat influence the glucose response. An egg adds protein and fat, may slow digestion, and can reduce the early rise after breakfast. The bread portion still matters, and “brown bread” is not always whole grain. Check the ingredient list and total carbohydrate per serving. Our carbohydrate and glycemic-index guide explains why both carbohydrate quantity and quality matter.



Your Tablet Increase May Be More Important



Because you changed breakfast and increased the medicine during the same period, it is impossible to credit breakfast alone. The effect depends on the tablet, dose, timing, kidney function, activity, and food intake.



Tablets such as gliclazide, glipizide, or glimepiride can cause low blood sugar, especially when meals are skipped. Metformin alone has a much lower risk, but every dose change still requires professional review.




Medication Safety


Tell your prescriber exactly which tablets you increased, the old and new doses, and your recent readings. A dose that corrected levels of 10–15 mmol/L may become too strong after dietary changes, illness recovery, weight loss, or reduced food intake.




Why Ice Cream May Seem to Have Little Effect



A single test may miss the glucose peak. Ice cream contains sugar, but its fat can delay digestion, so the rise may occur later. Portion size, medicine timing, activity, and meter variation also affect the result. Test at consistent times rather than deliberately challenging your glucose with sweets.



Good readings after sugary food do not make unlimited sweets safe. They still affect weight, triglycerides, dental health, and long-term glucose control. HbA1c and a structured glucose record are more useful than isolated readings.



Avoid Prolonged Fasting



Do not fast for an entire day simply to test how low your glucose will go. Your result of 4.5 mmol/L was not hypoglycemia, but prolonged fasting can cause low glucose with certain tablets. Glucose below 3.9 mmol/L (70 mg/dL) is considered low. If you are awake and able to swallow, take about 15 grams of fast-acting carbohydrate, wait 15 minutes, and recheck. See our low blood sugar treatment guide.



What to Discuss With Your Doctor




  • The name and dose of every diabetes medicine

  • Why readings suddenly rose after years of stability

  • Your fasting and 1–2-hour after-meal pattern

  • Your latest HbA1c and kidney and liver results

  • Recent illness, infection, steroid use, stress, weight change, or reduced activity

  • Whether the dose now needs adjusting



A sudden deterioration after 15 years may reflect progression of type 2 diabetes, but illness, stress, steroid medicines, poor sleep, or reduced activity can also raise glucose. Your clinician should review the cause rather than relying only on the breakfast change.




Seek Urgent Help


Seek urgent care for confusion, seizure, fainting, inability to swallow, or low glucose that does not improve. Also seek help for very high glucose with vomiting, abdominal pain, severe dehydration, unusual drowsiness, or rapid or difficult breathing.




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References




Medical disclaimer: This information is educational and is not a substitute for personal medical advice.



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