Sugar continues to sit atop the typical American menu. On average, people in the United States consume about 22 teaspoons of added sugar each day. That’s over three times what doctors recommend for women and more than double what they suggest for men. Although too much sugar has a clear link to metabolic diseases like diabetes, scientists say it’s been unclear what exactly causes such dysfunction. Now, a new study reveals the problem may be in how excess sugar damages the powerplants of our cells.

A team from the Van Andel Institute finds that too much glucose (sugar) disrupts the mitochondria of cells, making them less efficient at producing energy. Although the human body actually needs sugar to function, researchers say it’s easy for people to go overboard — quickly leading to poor health.

“The body needs sugar, or glucose, to survive, but, as the saying goes: ‘All good things in moderation,’” says corresponding author and Van Andel assistant professor Ning Wu, Ph.D., in a media release. “We found that too much glucose in cells, which is directly linked to the amount of sugar consumed in one’s diet, affects lipid composition throughout the body, which in turn affects the integrity of mitochondria. The overall effect is a loss of optimal function.”

What happens when the body takes in too much sugar?

Wu and her colleagues constructed a model which reveals that excess glucose lowers the concentration of polyunsaturated fatty acids (PUFAs) in the mitochondrial membrane of cells. Without the proper amount of these healthy fatty acids, the cellular powerplants become less effective.

PUFAs not only help the mitochondria do their job, they also control several other processes, including inflammation, blood pressure, and communication between the cells. When there’s too much sugar in the body, the excess does not become polyunsaturated fatty acids. Instead, they turn into a different form of fatty acid that disrupts the makeup of the cell membrane. This puts stress on the mitochondria, damaging them and making them less able to create energy for the body.

“Although we may not always notice the difference in mitochondrial performance right away, our bodies do,” Wu explains. “If the lipid balance is thrown off for long enough, we may begin to feel subtle changes, such as tiring more quickly. While our study does not offer medical recommendations, it does illuminate the early stages of metabolic disease and provides insights that may shape future prevention and therapeutic efforts.”

Can a diet change reverse this damage?

Wu’s team reversed the impact of excess sugar in an experiment with mice. Researchers fed the animals a low-sugar, ketogenic diet which restored the normal membrane lipid composition in their cells.

Along with sugar, the team also discovered that consuming too many carbohydrates reduces the healthy impact of PUFA supplements.