A friend of mine is a Type I, or childhood onset, diabetic. He's had it for nearly 50 years, since age 6. He's also in the health industry and is a good observer of detail.
He made the following interesting comments to me recently when talking about the effects of various foods on blood sugar:
"When I eat normally, like some vegetables or salad and meat, I dose up to 10 units of insulin to control my blood sugar.
"If I eat a turkey sandwich on two slices of whole wheat, I usually dose 15 units. The bread makes my blood sugar go to 300 if I don't.
"If I eat a Cousins's Sub [a local submarine sandwich chain], I dose 15 units. The bread really makes my blood sugar go up.
"I can only eat a Quarter Pound from McDonald's once a year, because it make my blood sugar go nuts. I dose 15-20 units before having it, and I feel like crap for two days afterwards.
"If I eat Mexican food, I have to dose 15-20 units. For some reason, it's gotten worse over the years, and I need to dose higher and higher.
"Chinese food is the absolute worst. I dose 20-25 units before eating Chinese. I'll often have to dose more afterwards, because my blood sugar goes so berserk."
Nothing beats the real-world observations on the impact of various foods on blood sugar than the observations of people with Type I diabetes. All the insulin they get is in a syringe. Dosing needs to match intake.
Personally, though I love the taste of Americanized Chinese food, I've always been suspicious of what exactly goes into these dishes. But I was unaware of the blood sugar implications.
The impact of Mexican I believe can be attributed to the cornstarch used in the tacos and tortillas, though I also wonder if there are other starches being snuck in, as well.