The season's sugary goodies can wreak havoc not just on your waistline—but your mind

Milk Duds. Swedish Fish. Sour Patch Kids. Even if you don't eat much candy, you probably have a soft spot for Halloween treats. Or maybe you get into the spirit of the season with a pumpkin-spiced latté?

In more ways that one, fall is sugar season. (That latté? The Starbucks version packs 49 grams of sugar into every 16 ounces-more of the sweet stuff than a can of Coca Cola!) And all that sugar can affect your brain in some frightening ways. Here's how.

Your First Bite or Sip

Your tongue's sweet taste receptors detect the sugary yumminess. They respond by sending signals to your brain's cerebral cortex, which fires up your reward system, explains Nicole Avena, Ph.D., author of Why Diets Fail. Sugar receptors in your gut further fuel this reward system response, she says. Your brain's reward system does a lot of complicated things. But Avena says its primary function is to answer the question, "Should I do that again?" When it comes to eating sugar, the answer is a resounding yes.

Specifically, sugar prompts the release of dopamine-a type of neurotransmitter that floods your noodle in response to pleasurable activities. Alcohol, nicotine, or illicit drugs all trigger the release of dopamine. As a result, each of these behaviors can lead to addiction, and sugar is no different. The more of it you have, the more you want, Avena says. In fact, a Connecticut College study suggests Oreos might be more addictive than cocaine.

Health experts are still sorting out why this effect exists. But since sugar is your body's primary source of fuel-and something that's hard to come by in nature-the human brain may have evolved to seek out sweets more than food. Basically, your brain wasn't designed to handle a world that offers you easy, cheap access to massive amounts of sugar, Avena says. Of course, fruit and some other healthy foods contain sugar too-just not in the same ultra-dense concentrations found in processed treats like cookies or candy, Avena says. Also, fruit contains other things like fiber that slow digestion, and so reduce the amount of sugar your system has to deal with all at once, she explains.

30 Minutes Later

The sugar from your sweet treat has made its way into your system, producing a state of hyperglycemia, or high blood sugar. While this is bad for your body in general, which has to store that excess sugar in fat or muscle cells to prevent it from poisoning your liver, research from the University of Minnesota has shown even short periods of hyperglycemia can mess with your attention span and memory. You also might feel down in the dumps, suggests a study from New York University.

Down the Road

Eat loads of sugar all the time, and your body's ability to handle it may break down to the point that permanent hyperglycemia develops. You know this condition by another name: Diabetes. Even absent of this disease, eating sugar all they time can hurt a bunch of your brain's functions. Everything from speaking and attention span to information processing speed suffers, shows a study from Tufts University. Eating lots of the sweet stuff has even been tied to a heightened risk for Alzheimer's.

Of course, none of this is an issue if you only have sugar once in a while. But again, eating sweets can snowball. If you feel like you're craving sugar all the time, the only way to break your habit is to wean yourself off one small step at a time, Avena says. For example, if you normally swig two sodas a day, cut back to one. Or, if you were eating dessert every evening, try to skip nights here or there, or cut down your portion sizes. "Cold turkey doesn't work," Avena stresses. "You need to re-train your brain to crave healthier foods."