A few comments for you -
I too have diabetes. Have you joined
www.diabetes.org.uk? They have lots of information and advice, though not specifically on hiking & backpacking, but their forum is good, with lots of active & helpful members
As I mentioned, have a good look round a big supermarket
You will find various foods in pouches by
www.merchant-gourmet.com and others, like supermarket own labels
wet/RTE pouches of rice from John West, Tilda, Uncle Ben's
This brings us to the weight of food, where you have the same problem as the rest of us - which is best - MRE and less fuel or a lighter dried meal and more fuel? Or an AFD meal which only requires water to be boiled, but is more expensive? Oho, have fun with that!
Yes, MREs are heavier than dried, but I wouldn't have thought that even 4 or 5 would be excessive; after all, the weight will be going down each night
You don't have to boil rice or pasta continually, just bring to the boil and let it soak; try a pot cosy
I don't like glucose tablets for instant sugar. You can use jelly babies but they tend to clag together in a rucsac in hot weather; liquorice allsorts are more substantial
Make up your own nuts/raisins/sultanas mixture then you can add M&Ms or not as you wish
I take dried fruit; dates, figs, or apricots
Have a look round a health food shop, Holland & Barrett is the most common. They have various tubes & tubs of pastes, pates, cheese substitutes and other things. Ask the staff, they will know their products and advise you
You seem to do the water business in a big way. I have 2 x 1,8l platypus bladders for use when camped plus a 750ml bottle during the day. And a few purification tablets in my first aid kit
The situation is self adjusting. In the hills the water is usually good enough to drink raw, and at lower levels you are more likely to use a campsite or pass farms & houses
If you're going to buy ready made backpacking meals it would be worth joining Go Outdoors discount scheme and /or Surfing the Net for the best prices
I'm puzzled. All packaged food has a lists the composition and nutritional breakdown, so why is food with a sauce a no-no, but shepherd's pie & mash (meat & gravy, which both have fat, & carbohydrate) acceptable?