Her patients are addicted to a substance that is molecularly similar to cocaine, and they sometimes experience painful headaches as a result of their withdrawals.

The culprit: sugar.

“I work with adults … who have to break [their] sugar addiction,” said healthcare professional Jessica Hicks in a phone interview. “It becomes very hard for them, and it takes a lot of practice and [behavior-changing] habits.”

Hicks, a registered dietician and certified diabetes educator at NorthShore University HealthSystem, said the brain gives the body reward sensations for eating sugar because it recognizes sugar as an easy source of energy.

Paul Jacques, director of the nutritional epidemiology program at the U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, said in a phone interview that consuming any type of sugar in small quantities is not harmful because it can be digested and used for energy by the body.

“The problem is the amount of sugar we’re consuming,” said Jacques. “[Eating too much sugar] overwhelms our body’s ability to metabolize sugar.”

He said the maximum amount of added sugars people can have per day depends on their physical activity and body size.

“Less than 10 percent of calories [should come from added sugar], … so for someone consuming 2,000 calories a day, they wouldn’t want to consume 200 calories of added sugar,” Jacques said.

According to Jacques, although U.S. dietary guidelines allow for added sugar in our diets, added sugar is not necessary to consume at all.

“Our body can convert the other foods we eat into sugars that we need … for energy,” he said.

According to Hicks, sugar consumption can affect various organs within the body and impede their ability to function properly. When a person consumes too much sugar, the liver stores the extra sugar and becomes coated in fat. This condition, called non-alcoholic fatty liver, can prevent the liver from releasing energy when the body needs it. Excess sugar can also cause pancreatitis, which is inflammation of the pancreas, and increases risk for pancreatic cancer.

Jacques said although too much sugar can lead to obesity, just because a person is not obese does not mean he or she has not been impacted by the negative effects of sugar consumption.

“You also have individuals who are lean, who consume sugar-sweetened beverages and still have a disorder with their metabolism [which is] classified as diabetes,” said Jacques. “[There is also an] increased risk of heart disease.”

Sophomore Alexandra Chertok, a member of the Glenbrook North varsity cross country team, said she feels more fatigued when she eats sugary foods.

“If I eat stuff that has a ton of added sugar, … then I just won’t feel as energetic,” said Chertok. “My legs just feel heavier when I run.”

Senior Skyler Metzger said he can feel the effects of added sugar on his body soon after he eats it — a burst of energy followed by a sharp crash.

According to Hicks, the sugar crash comes from the body using up energy when it is trying to process the excess sugar.

“Your body is exhausted from [digesting] all of that excessive sugar and your brain is just totally fatigued,” Hicks said.

According to Hicks, different types of sugars enter the bloodstream at varying rates. A type of sugar with a low glycemic index, like honey or light agave, does not spike blood sugar as quickly, will provide longer lasting energy and will only cause a small crash. A substance with a high-glycemic index, like darker colored agave, table sugar or high fructose corn syrup, will cause a large spike in blood sugar.

Jacques said he believes the distinction between eating different types of sugars is less important than the difference between consuming added sugars or not. Natural and added sugars have chemically similar effects on the body, but consuming foods with no added sugars can bring other nutritional benefits.

“If we’re getting that sugar from a fruit — from apples, berries or oranges — we are getting other nutrients with that,” said Jacques. “But if you’re drinking sugary beverages like sodas and juice drinks … you’re not getting any other nutrients with that sugar.”

According to Hicks, when many people attempt to reduce sugar consumption, they end up reducing the amount of healthy carbohydrates they eat as well. An easy way to find less sugary alternatives without compromising healthy carbohydrates is to look for high-fiber foods.

“Instead of drinking the juice, eat the fruit,” said Hicks. “Or maybe choose the [carbohydrate] that has higher fiber.”

According to Chertok, she looks at the types and quantity of sugar when she reads nutrition labels.

“There’s like 20 different names for saying [added] sugar, so I make sure there’s not too much,” Chertok said.

However, she said she prefers to eat natural foods that don’t have labels, such as fruits and vegetables.

“If it’s natural, like, it’s probably better for you than processed things that may be low-fat but have a lot of sugar or have, like, xylitol or erythritol, fake things that just metabolize as sugar anyways,” Chertok said.

Hicks said the ultimate key to a healthy diet is avoiding consumption of food in excess, and is even more important than avoiding added sugars.

“It’s hard to say if something is really good for you or really bad for you,” said Hicks. “Have sugar in moderation and [try not to] overconsume anything.”