Photo by Sharon McCutcheon on Unsplash

ZÜRICH, Switzerland — Saying that consuming too much sugar is unhealthy is not exactly breaking news. However, a new study is revealing what even a modest amount of extra sugar is doing to the human liver. Researchers from the University of Zurich say consuming fructose and sucrose doubles the body’s fat production in the liver. In the long run, this can add up to the development of diabetes or fatty liver disease.

In the research team’s home country of Switzerland, the average local takes in over 100 grams of added sugar daily. These foods and drinks usually have a high calorie content, putting consumers at risk for obesity and other weight-related conditions. Numerous studies have discovered this connection. Researchers in this report wanted to see what else added sugar is doing on a daily basis.

Unlike older studies which examined what large amounts of sugar does to humans, study authors at the University of Zurich and the University Hospital Zurich discovered even lower amounts alter the body’s metabolism. Their study finds even if a person stops consuming sugar, the effect can linger.

“Eighty grams of sugar daily, which is equivalent to about 0.8 liters of a normal soft drink, boosts fat production in the liver. And the overactive fat production continues for a longer period of time, even if no more sugar is consumed,” says study leader Philipp Gerber of the Department of Endocrinology, Diabetology and Clinical Nutrition in a university release.

Which sugar is the worst for your health?

Researchers examined 94 healthy young men during a seven-week experiment. Each participant consumed a sweetened drink with one of three types of sugars in it. These included fructose, glucose, and sucrose — the last one being regular table sugar which is a fructose/glucose combination. For comparison, a group of control participants did not have any added sugar.

Study authors also used tracers during the tests; substances which scientists can follow as they move through the body. This allowed the team to study the impact of the sugary beverages on fat metabolism.

The results reveal participants who had the sugary drinks did not end up taking in more calories than usual. The team believes this is because these drinks increase the feeling of fullness and the participants therefore took in less calories from other foods. Despite not adding calories however, researchers discovered the negative impact of the sugar itself.

“The body’s own fat production in the liver was twice as high in the fructose group as in the glucose group or the control group – and this was still the case more than twelve hours after the last meal or sugar consumption,” Gerber explains.

Even worse, the scientists reveal sucrose boosted fat production slightly more than the same amount of fructose. The team adds that people are more likely to consume sucrose on a daily basis. Until now, researchers believed it was fructose that causes more of these body changes to occur.

Why is all this sugar and fat production bad for you?

When the liver produces more fat, it commonly leads to the patient developing type 2 diabetes and possibly fatty liver disease. The Centers for Disease Control and Prevention estimate that over 30 million people in the United States have type 2 diabetes. Serious cases can lead to heart disease, vision loss, and kidney problems.

In comparison to the Swiss average (100g of sugar daily), the World Health Organization recommends limiting daily sugar consumption to about half that amount. If possible, they recommend pushing that number down to 25 grams.

“But we are far off that mark in Switzerland,” Gerber concludes. “Our results are a critical step in researching the harmful effects of added sugars and will be very significant for future dietary recommendations.”

The study appears in the Journal of Hepatology.

About Chris Melore

Chris Melore has been a writer, researcher, editor, and producer in the New York-area since 2006. He won a local Emmy award for his work in sports television in 2011.

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