Our kids bring home oodles of goodies each Halloween. Then comes the guilty-pleasure part—chowing down on all that candy. Adults are in the same boat as children, with many consuming even more Halloween treats than do kids—whether the candy’s absconded from their brood’s stash, from bowls in workplace break rooms, or elsewhere.

Should we be concerned?

Before answering this question, let’s put Halloween into context. Halloween is the big kahuna of U.S. candy-dominated holidays, followed by Easter, Christmas, Valentine’s Day, and Mother’s Day. Between all these holidays Coloradans eat about 20ish pounds of candy per year. By “candy,” we’re talking about chocolate, licorice, suckers and the like. Kids eat about 3–5 pounds each Halloween.

Candy is delicious. But it’s challenging. Two of those fun-size candy bars contain more sugar than a can of full-strength Coke—the equivalent of gulping about 10 teaspoons of white table sugar. Yowza!

Halloween is the biggest holiday in terms of sugar. Ever wondered what exactly sugar does to the body? Does it actually make kids hyper? What is the risk of diabetes? Science columnist James Hagadorn presents the facts about sugar.

The most common concern about Halloween candy is the same one that we hear at birthday parties: that all this sugar makes kids hyper. It turns out that scientists and psychologists have debunked this urban legend many times and in many ways. A sugar blast doesn’t alter kids’ behavior in such settings—not in boys, girls, kids with ADHD, or those without. This urban legend is a classic example of the difference between correlation and causation. We observe kids eating a ton of candy or cake, then we note their rambunctious behavior, and we conclude that one must cause the other.

But these events are correlated, not causal. What tends to happen in this setting is that other factors associated with these events (being excited, scared, tired, having skipped dinner, dressed up, etc.) cause kids’ behavioral changes. Moreover, parents, because they “believe” that they know what will happen with their kids’ post-sugary behavior, also unknowingly change their own behavior and expectations. This changes the way they perceive their kids’ behavior and the way they interact with their kids, including the way they warn, criticize, time, and discipline their kids. In some cases, parents impact the way children behave by telling them that they’ll be hyper after eating so much cake/candy/sugar.

Rowdy behavior aside, the real issues with all this candy are longer-term and more hair-raising than any haunted house. They include scary-sounding phenomena such as prediabetes, diabetes, obesity, and tooth decay.

Like HIV, these conditions don’t kill you directly—but they make it easier for other maladies to mar your life.

They occur not with a few nights per year of candied abandon, but with daily long-term dosing of our bodies with what’s called “free sugar” or “simple sugars.” This is what’s in candy, juice, soda, cookies, honey, corn syrups, and processed foods. In Colorado we eat ~120–150 grams of these so-called “free sugars” per day, but the World Health Organization recommends that we eat much less—not more than 25–50 grams per day. That’s the equivalent of about 6–12 teaspoons of sugar, much of which we consume in “so-called healthy” foods such as yogurt, energy bars or juices without ever eating candy and desserts. Add a Snickers and—egads—I’m way over that limit, even without Halloween!

Sugar isn’t quite in the same league as tobacco, because we need a little bit of it to thrive. But it’s getting there.

For example, our high-calorie, sugar-rich diets can lead to a prediabetic condition known as metabolic syndrome, or “prediabetes.” In this situation, our bodies regularly have higher levels of insulin, a sugar-regulating hormone produced by special cells in our pancreas, termed islets. Higher insulin levels result from excess sugar consumption and lead to obesity. When we’ve had a sugar-rich diet for a long time, we become less sensitive to insulin and these insulin-producing cells become overtaxed and exhausted. This is when prediabetes gives way to Type 2 diabetes. It’s like what happens to the long-battered liver of an alcoholic—except there are a lot more of us harming our pancreas than those who damage their livers.

The scary part: One in three Americans has prediabetes.

The alarming part: Prediabetes lacks any external or obvious symptoms.

The good news is that Colorado, save its rural areas, lags the rest of the U.S. in these conditions. But we’re catching up—our prediabetes and diabetes rates, like our obesity rates, have doubled in the last 20 years.

Fortunately, these things needn’t haunt us because we can change the future. Prediabetes, like obesity, is readily resolved by tempering our intake of sugar and by increasing exercise. Exercise helps to reduce blood sugar levels and to diminish prediabetic insulin resistance.

We don’t have to swear off Halloween candy, but perhaps just eat it in moderation or in consideration of the overall mountain of sugar that our poor ol’ pancreas has to deal with every day.

James Hagadorn, Ph.D., is a scientist at the Denver Museum of Nature & Science. Suggestions and comments are welcome at jwhagadorn@dmns.org