Complex carbohydrates, especially in conjunction with more fiber (think whole grains) release sugars very slowly. You do need these for backpacking--the exercise is going to reduce your blood sugar considerably and without carbohydrates you may find yourself with hypoglycemia (too low blood sugar). Just be sure they are the right kind of carbohydrates! Whole grains, not white flour, white pasta or white rice (basically empty calories), not energy bars full of sugar or, worse yet, candy bars!

Try searching on this section (see the "sticky" post at the top of the General Discussion Section on how to search; be sure to change the default date parameters); I know there have been a number of posts in the past on diabetic backpacking diets. You're not alone!

Nuts are excellent and contain healthy (i.e., monounsaturated) fats.