Give Me Candy: How Sugar Really Affects Your Body


Sugar! Sugar! Don’t we all need some sweet donuts and milk tea on this fair day? Maybe you woke up this morning craving some Oreos and Sour Patch Kids? Are you feeling fatigued by the never-ending research projects or the frustrating lab reports? Me too. That is why we will be talking about the most common binge eating / coping food item: sugar.

Have you ever experienced or heard other people describe the sugar high – a surge of unexplainable excitement that prompts energetic behaviors? Have you ever wondered what makes sugar so tasty and addictive? And what exactly does sugar trigger in the brain that makes us crave sweets so much? I mean, what does the consumption of sugar actually do inside our bodies that makes it such an essential part of the human diet?

  1. What exactly is sugar?

There are several kinds of naturally occurring simple sugars. The most prominent three are glucose, fructose, and sucrose. There are also other sugars, like lactose, maltose, dextrose, and starch, but we won’t be going too deep into the others today. Glucose and fructose are monosaccharides, the simplest and most basic unit of carbohydrate. When glucose and fructose are combined, they become a sucrose, a disaccharide sugar molecule. What are the differences of these three sugars? Well, you might already know that glucose is also called blood sugar and is our bodies’ preferred energy source. The carbohydrates we consume (like the delicious baked goods on the left) will most likely be broken down into glucose for energy that will be used and stored by the body. Glucose is so essential that our bodies secrete insulin to regulate the glucose level in the blood stream.

Fructose is found in fruits and vegetables and is not the energy source for our bodily functions. It can only be metabolized in the liver and does not trigger an insulin response at all. Therefore, constantly over-consuming fruits or dietary fructose (found in sodas and flavored drinks) can be problematic because there is less indication of how a high fructose level affects the body. Last but not least, sucrose (also known as table sugar) is the combination of glucose and fructose and can be obtained from sugar beets and sugar cane. Because glucose and fructose are processed differently after consumption, the two parts of sucrose will be taken apart to be metabolized and used by the body¹.

2. How it affects our brains

Why do you crave brownies, candy bars, waffle cones, and ice cream? What happens in our brain that screams “I need dessert” after a hearty, savory meal? Why can’t kids (or adults) resist the temptation of candy? It turns out it all happens in our brain. When you eat sugar, the taste buds on your tongue immediately recognize the sweet taste and send signals up to the brain that identify the presence of something you really like². A complex reward system in the brain is then activated, which makes you want to taste it again. The consumption of sugar causes the release of dopamine – the feel-good neurotransmitter –, which explains why we love eating sweets.The more dopamine that is released, the better we feel. So what causes us to stop eating sugar? Fortunately, there are sugar receptors in the stomach and intestines that send signals of “I am full” and “More insulin, please” to the brain to balance sugar consumption³.

  1. The placebo effect

Remember the sugar high we were talking about? Well, it turns out that sugar high is something that happens exclusively in your head too. According to Scientific American, parents often overestimate the effects sugar has on their children. In an experiment, the parents who were told their children consumed sugar were more likely to report hyperactive behavior by their children than did those who were not. In conclusion, our culture brands candy bars, cookies, ice cream, etc. as agents that cause hyperexcitation, but most of the time, it is simply the placebo effect playing its tricks on you. The placebo effect is a neurobiological phenomenon that can create expectation on an subject (like candy) and create the perception of a certain effect that is triggered by that subject (sugar high) that has nothing to do with the properties of that subject (sugar does not cause hyperexcitation).Here is a comic that will further discuss the curious placebo effect in more details.

  1. How it affects our health

Even though sugar does not really trigger hyperactive behavior, it still has a great impact on our bodies and is universally present in our diets. Sugar exists not just in desserts but also in ketchup, granola, yogurt, etc. Therefore, it is important to understand what it does to our bodies. Any time sugar is consumed, it triggers a series of effects in the brain that cause a rewarding feeling, but overconsuming sugar can lead to addiction. According to the American Diabetes Association, although sugar has nothing to do with Type I diabetes (an autoimmune disease), it does have a whole lot to do with Type II diabetes, which occurs when insulin receptors no longer receive insulin signals because blood sugar regulation has been so abused. Being overweight and living on a diet with high calorie levels increase the risk of diabetes. Consumption of sugary drinks and high-calorie, low-nutritional-value foods can also increase the chance of being overweight and unhealthy. As humans living in the 21st century, we live in a world of instant gratification and overindulgence, but our bodies are not evolutionarily designed to consume as much sugar as we do now. You see, our ancestors, who lived without refrigerators and biotech factories, relied on only natural sugar sources like fruits, which are often seasonal and thus not always available. However, as long as you are eating moderate portions of sweets, you won’t abuse the reward system in your brain and the insulin receptors in your body. You should feel free to enjoy the gift mother nature gave us: sugar.