American kids are consuming huge quantities of sugar, and it’s leading to obesity and hyperactivity in schools — but there’s good news.

New research out of the University of California-San Francisco and Touro University sheds light on the sugar intake of American kids by examining 44 volunteers between the ages of 9 to 18 to understand how their bodies respond to being put on low sugar diets, according to a Washington Post report.

All of the kids were obese and spanned several races, and each of them had a metabolic health issue, including high blood pressure and other health problems.

Using oral glucose tolerance tests, bone density scans, cholesterol counts, and other extensive tests, scientists wanted to know every aspect of their health. They also had parents fill out food questionnaires to further understand their diets.

Using this information, they created a new diet that slashed the amount of sugar and replaced it with starch, and they were started at the results: simply replacing sugar with starch without changing the amount of calories they were consuming or increasing their level of exercise, all metabolic health measures improved, said Robert Lustig, the study author and a pediatric endocrinologist at UCSF Benioff Children’s Hospital San Francisco, according to the report.

In just 10 days, diastolic blood pressure went down, as did the amount of bad cholesterol, despite the fact that the amount of calories they were consuming was relatively unchanged. Furthermore, they lost about two pounds in that brief period, and in some cases researchers had the increase the amount of calories they were feeding them to keep them from losing weight too fast.

The findings were published in the journal Obesity.