One of the required criteria for meeting Canada's Disability Tax Credit eligibility is that it takes you 14 hours or more a week to manage your diabetes.
The calculation does NOT include counting carbs. Exercise and actually eating are not counted, either.
The disability tax credit form application is used for many disabilities but, as far as diabetes goes is mostly used by parents of Type 1 diabetic children (who needed regular testing and injections; monitoring by an adult) or those on an insulin pump. For an adult, it's extremely difficult to meet eligibility and there are a number of forms your doctor has to fill out. If you are approved, it's also for a period of time and then you have to reapply.
Also in Canada, if your medical receipts add up to a certain amount (like over $3,000) or more than a % of your income (I forget the amount), then you get some money back. There's a line somewhere on the tax form for this. It's not an application process.
I think I might make the medical amount if I included all the candy I use to fix lows