Growing up, whenever I visited my grandpa's place, he had snacks all around the house. I remember that he ate all day, but never ate a full dinner. And here's why: The human body runs on carbohydrates as its main fuel, thus, carbs are our primary macronutrients (1p105). Glucose is the most important carbohydrate because of its direct involvement in signaling insulin, its uptake into muscles and in glycolysis providing energy (1p105).
If concentrations of glucose are below normal, the body is hypoglycemic (1p105). To be precise, three criteria determine a disorder of true hypoglycemia: low serum glucose level, presence of andrenergic or neuroglucopenic symptoms, and relief of symptoms when eating a meal with carbohydrates that return serum glucose to normal levels (1p105). What if a person has low serum glucose, but no other symptoms (1p105)? Or what if a person has adrenergic or neuroglucopenic symptoms, but normal glucose levels (1p105)? Well, it's complicated (1p105). Neither are true hypoglycemia (1p105).
Two types of true hypoglycemia disorders exist: fasting hypoglycemia and fed (reactive) hypoglycemia (1p105). The first is typically caused by drugs like exogenous insulin used to treat type 1 diabetes, sulfonylureas, which stimulate insulin secretion, an insulinoma, or intake of excessive alcohol (1p105). The second is caused when patients have impaired glucose tolerance or idiopathic postprandial syndrome (1p105). In these cases, post-prandial insulin response may be delayed, followed by an excessive insulin release that drives glucose down too far (1p105).
My grandpa had fed (reactive) hypoglycemia. He was good about his treatment with diet therapy and, as appropriate, he avoided simple and refined sugars and tried to eat frequent and small snacks with mixed proteins, carbs and fats (1p105). Still, my personal belief is that he could've done a little better. The easy $1 Burger King Whopper got the best of him and we lost grandpa a few years back to coronary artery disease.
1. Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. Belmont, CA: Thomson Wadsworth, 2009.