To make it easy to remember, we call it the Rule of 15. Eat/drink 15 carbs and wait the longest 15 minutes of your life to re-test your blood sugar. (Hey, low blood sugar is scary stuff.) It is not necessary to be back to your target blood sugar in 15 minutes, just moving in the right direction. Over-correcting by going hog-wild in the candy store is just as dangerous.
What you should eat or drink depends on what’s around. Low blood sugar is a potential emergency. You don’t want to pussy-foot around. Liquids are fastest. Half a regular soda will do. As will a couple spoonfuls of honey. Hard candy can work fine.
Sorry. No chocolate. Good for the soul, yes. And maybe the heart. But not good for low blood sugar. Most chocolate candy is also high in fat and fat slows down the sugar from getting from your digestive system to your blood, where it needs to be.
Of course the very best plan is to plan ahead. Anyone on insulin or other diabetes medications that might lower blood sugar should always have some emergency supplies with them at all times. There are a number of very effective over-the-counter glucose products at any drug store. Glucose comes in liquid “shots,” tablets, and jells.