When hypo, selfish Brain demands all available glucose, so that your “unnecessaries” (including gastric tract) shuts down and it is advisable to keep it simple (i.e. glucose) when it comes to the stuff you shovel in. Most of the bouncy bits (including Jelly Babies & Fruit Pastilles) contain cow’s foot and requires some digestive prowess, which your hibernating gut can’t provide…my quickie involves glucose powder*, dissolved in water.
* Glucotabs (4 of them) here only available as part of a tiny&expensive kit (also contains a sachet of that hideous blubber mentioned by @stephen), costing as much as 1kg of glucose powder/diabetic cocaine…haven’t tried snorting it, though 