Consuming caffeine and sugar together can trick the brain into believing that the blood sugar level is too low, even though it is above the threshold for hypoglycemia. Caffeine affects the brain in two ways, it drops your blood flow in your brain and at the same time it tells the brain to demand more glucose (sugar). So it has this dichotomy, and the end result is that the brain thinks it's getting less sugar than it actually is... Now we're not talking about a huge dose of caffeine here, we're only talking about 2 to 3 cups of coffee.. The results were presented last week at the 57th Annual Scientific Sessions Meeting of the American Diabetes Association in Boston.
The brain is very sensitive to blood sugar levels because it requires a constant supply of glucose, yet it cannot store the energy source in the same way that muscle and liver can. Given the brain's sensitivity to blood sugar levels, a decreased blood flow to the brain coupled with a slightly lowered (but not hypoglycemic) blood glucose may cause the brain to perceive a false state of hypoglycemia. It might explain why from time to time people have some bizarre symptoms which they used to (attribute) to hypoglycemia.
Contrary to intuition, consuming a load of sugar actually decreases blood sugar levels. Although there is an initial rise in blood sugar levels, the body reflexively responds by producing insulin, which signals cells to take up sugar from the blood, ultimately resulting in a slightly lower than normal blood sugar level. The symptoms normally attributed to hypoglycemia are shaking, sweating, intense hunger, difficulty in thinking properly, and impaired performance at work or with complex machines.