Not a strange request at all .There are a few of us skinnies here .I suggest asking to see a dietician and explaining that you want to keep your BGs down and your weight up .I.dont know if you reduce your carbs to help your BG level but if you do you need to eat lots of calories I find cheese ,cream ,butter and some pulses help but you can get some additional help from the GP for eg a product called Calogen which is a liquid made up of oils ,it is pretty nasty but it does the job.
CAROL