Welcome Paul,
You're not alone. Many if not all of us are frustrated with the skills we supposedly learn from our health care teams. That's why we're here. Blue Sky's right about the rates. Once you learn your optimal rates and maybe a few techniques to control spikes, everything else seems to fall into place.
Some quick reading:
Getting Down to Basals :: Diabetes Self-Management
As far as diet goes, there is no such thing as a diabetic diet. In fact, you are right, what they tend to promote is more likely to kill us than make us healthy. I've always intuitively avoided the diabetic cookbooks.
What to eat is actually quite simple:
Eat Food. Not too much. Mostly Plants. Many on here will exchange plants for protein. I have no issue with that as long as you get enough carbs to function
normally. I'm curious why do you need to gain weight. Are people hanging flags from you?
Michael Pollan on The Hour with George Stroumboulopoulos on CBC