If you are ending a period of not eating your body has been maintaining a minimum glucose level by turning fats (and lacking fats, protein) into glucose. That system is controlled via glucagon from alpha cells in the pancreas. If you start your fast breaking meal with simple carbs, there will be both glucose from converting fats/protein plus whatever you're consuming. Cold liquids with sugar are probably the worst as your stomach will push that into your small intestine quickly (handy bit of trivia if you're dealing with a diabetic with a low sugar emergency).
Not a bio/med pro, just got interested when my dad was diagnosed with T2DM. Been reading bio/med textbooks and studies since then (90s). Wish we knew back then what we know now...