Science has already broken hearts with the news that comfort food doesn't exist. Now, we regret to inform you that there actually isn't any conclusive evidence of increased hyperactivity after ingesting a ton of sugar. In other words: Your sugar high is a lie.
Much of the sugar-hyperactivity hype can be traced back to 1973 when allergist Benjamin Feingold, M.D. published his Feingold Diet. Although this plan didn't specifically call for eliminating sugar, it did recommend against parents feeding kids foods containing artificial flavors and colorings, suggesting that these might cause hyperactivity. So, for many, this naturally extended to sugary treats.
But, since then, analyses of several double-blind, randomized studies, show that kids given sugar do not reliably act more energetic than those who get placebo candies (which are a depressing concept on their own). These studies have included sucrose, aspartame, and saccharin from chocolates, classic sweets, and natural sources. Even in kids who are considered "sensitive" to sugar, the reported rush couldn't be replicated.
I hear you protesting. And, I believe you. If you don't normally ingest that much, chowing down on a bunch of candy does a couple of powerful things. First, it causes the release of endorphins and dopamine, so you might feel a bit more "up" after taking down that chocolate bar. And, some evidence suggests a link between ingesting sugar and the release of adrenaline. But, adrenaline can also increase glucose levels, so it's not clear exactly which direction this effect is heading.
As we delve deeper into this can of gummy worms, we should point out there's still a bit of evidence suggesting that artificial colors (including those in sugary candies) can make kids hyperactive. So, the candy might still be responsible, even if the sugar isn't. Although the FDA's on the case, this debate has not been settled.
If the sugar rush is mostly a myth, does that mean that a sugar crash isn't real either? Not necessarily. Chowing down on candy can cause an insulin spike. And, when insulin secretion and blood-glucose levels drop back down, you might get a headache and feel a bit fatigued or irritable. These are commonly-reported symptoms of hypoglycemia, but actual hypoglycemia can be severe and often occurs in people with diabetes. So, we're not talking medical emergency-level here, but you might need a quick nap.