My four year old daughter has type 1 diabetes and will get a high reading before dinner, followed a low reading before snack that the doctor explains is due to the afternoon exercise kicking-in. We’ve received a lot of information on how various types of insulin work, but need more information about the effects of different foods and exercise.

This is a neat question. I wish I could give you an easy answer, but I can’t. I often preach that “all carbs are not created equal” (which gives my dietitian and nurse educator friends and mentors the cringes). Different foods are absorbed and metabolized and converted into glucose differently.

Simple sugars (like in juice, glucose tablets, cake frosting) can begin to raise the blood sugar in about 15 minutes. Honey sometimes takes a little longer. More complex starches take longer to be digested. Proteins can take hours to be converted into glucose, and, to confound issues more, if there is fat in the diet, it can delay the absorption of carbs, even some of the fast-acting ones. So eating pizza, a childhood favorite, is hard for many folks to judge and anticipate how it will affect glucose readings. Further complicating matters is whether or not the child is recovering from (or about to get) the flu so again there is not always a constant as to how foods are absorbed.

Exercise is another bug-a-boo. For many kiddies, exercise brings glucose readings down in a couple of hours, but in some, the glucose readings increase first, only to come way down several hours later. This seems to be pretty individualized from patient to patient.

DS
Additional comments from Delaine Wright:
In addition, I would add that if this is observed as a daily pattern, then your diabetes team should be able to assist you in attempting to match food intake and insulin dosaging to your daughter’s activity level. Not always an easy thing to do with a young child perhaps, but the idea would be to level out those lows and highs. Again, if the lows prior to afternoon snack & the highs before dinner are a daily occurrence, perhaps a change in the composition of the lunchtime meal might help (i.e., additional protein, or complex carb) to help keep blood sugar levels appropriate during afternoon activity. Snacking a little earlier than you are currently doing is another option. A dietitian is a wonderful resource in this situation. Perhaps, too, a decrease in the long-acting insulin may be necessary, which might change the need to adjust food intake. Talk to your diabetes team about these options.

Regarding exercise information, the book The Diabetic Athlete by Sheri Colberg and Edward Horton is a favorite recommendation of mine. It contains lots of information about the effects of exercise on blood sugar management, including tips on carbohydrate and protein intake, and insulin types in relation to activities.

DMW