If you want to, you can try to do a glucose test on yourself. I can send you a meter and some strips... I posted somewhere else on here the protocol for doing the test at home, with a meal, instead of the glucola crap. That way, you'll get three hours' worth of testing, which is *way* more accurate than the 1 hour GD test.
Anything with carbs in it is going to affect your blood glucose. Protein powders probably don't have many carbs, but the juices, fruits, breads, pastas, anything white, will affect you. Strawberries are the best fruit since they are low glycemic, meaning the sugars in strawberries will have a slower effect on blood glucose. Any other fruit is really high glycemic, unfortunately. Bananas are high, surprisingly. You'd think only citruses were, but no.
Higher protein diets are usually used by "regular" diabetics. We tend to try and keep lower carb, less than 30gms per meal, 20gms per snack. I shouldn't say "we", I'm not a low carber, since I enjoy my carbs. But, if you have to control by diet and not with insulin (like all T1s), then the low carb diets help a ton. Also, aerobic exercise helps bring sugars down, whereas strength training will bring them up.