Three questions: how much protein is included in your lunch on days this happens? What are you eating for your snack at 4 pm (and how much later than that are you cooking dinner?) And last, what kind or kinds of insulin are you taking? A late afternoon low is not unusual with some varieties of insulin, and usually that is why the afternoon snack is recommended. If you are not having enough protein at lunch or not including protein in your snack, you can still fall low. Insulins have different peak times as well, so you need to track backwards to what time you are taking your insulin to find a common denominator. If you are taking short-acting insulin WITH your lunch, is it on a sliding scale so that you don't take as much if you are in control at that time? Lots more questions than answers I'm afraid, but this can be resolved by either adjusting down a short term shot taken at lunch or bumping up your protein levels. "Small snack" should include at least a little protein, which protects you against these lows. Hope you resolve the issue!