Carbs have such a bad rep that many people avoid them completely because they're worried of gaining weight, or that they have an intolerance to gluten, a protein found in some grains. However, carbohydrates are actually your body’s main fuel source.

There’s different types, which often confuses people. To better understand the basics of carbs and to learn what happens when you eat too many, watch the video below hosted by Vanessa Hill from PBS Digital Studios.

Read: What Are Good Carbs? 5 Ways To Stay Healthy While Eating 'Forbidden Foods'​

Carbs are comprised of three main categories: sugars, starches, and dietary fiber. There’s healthy ones, like whole grains, vegetables, fruits, and beans. Other less healthy sources include highly processed or refined foods, like white bread, pastries, and sodas.

In short, carbs are sugar molecules which your body breaks down into energy. The most important sugar molecule is glucose, which provides all your cells with energy. Your brain relies on glucose and if you don’t have enough, you can start to get shaky, lightheaded, and confused.

But, what happens when you eat too many carbs and have too much glucose?

If your body has too much glucose, it will package it up and store it for a later time when you need more energy for things like exercising or thinking, Hill explains in the video. This is why some athletes will go on a carb-loading diet.

When your brain has too much sugar, this can be detrimental to your body and contribute to cell aging and possibly dementia and other neurodegenerative conditions.

Fortunately, for most of us, our blood sugar level is regulated, thanks to insulin. However, if you frequently have too much sugar, your body can develop insulin resistance. Over time, insulin resistance can lead to prediabetes, and type 2 diabetes.

But, before you worry about carbs being full of sugar, remember that food is fuel, even carbs; moderation is key, Hill advises.

See also: How To Eat Carbs And Still Lose Weight: Resistant Starch Foods Improve Gut Bacteria

Good Carbs, Bad Carbs: 5 Common Myths About Carbohydrates That May Be Ruining Your Digestive Health