Meals, Timing and Medication
Reviewed by CDE Mehandi Sharma · Updated
Timing rules in diabetes are not arbitrary. They come from how each medicine works, so they change when your medicine changes.
| Treatment | What timing demands |
|---|---|
| Metformin alone | Take with or after food to reduce stomach upset; meal timing itself is flexible |
| Sulfonylurea | Do not skip a meal after taking it — a missed meal can cause a low |
| Basal insulin only | Roughly the same time each day for the injection; meals stay reasonably flexible |
| Basal plus mealtime insulin | Dose is matched to the meal, so meals and injections travel together |
The direction of travel is towards more structure. Early on, a late lunch is a minor thing. Once mealtime insulin is in the picture, insulin taken and food not eaten is the most common cause of a low.
Some habits that help throughout:
- Keep roughly consistent meal times rather than eating whenever the day allows.
- Keep portion sizes similar from day to day — it makes your readings interpretable.
- Never take mealtime insulin before you are sure the food is actually arriving. In a restaurant, wait until it is on the table.
- If a meal is delayed and you are on a sulfonylurea or insulin, carry something to bridge the gap.
Each time your regimen changes, ask specifically what the new timing rules are. Assuming the old ones still apply is a common way to run into an unexpected low.