Sweet potatoes are packed with tons of vitamins, but could they offer more nutrients without even being eaten?

A new study published in journal Heliyon found that proteins in starchy wastewater from cooking sweet potatoes actually reduced both fat levels and weight in mice.

Researchers originally wanted to find a new way to utilize sweet potato waste, so they investigated how the digestion of mice responded to these proteins from the wastewater, according to a recent statement.

The research team split the participating mice into three groups and administered varying levels of sweet potato peptide (SPP), which is produced by enzymes digesting proteins in the water. One group received a high concentration, one got a lower concentration, and the other had none.

After 28 days, they weighed the creatures and measured their liver mass and fatty tissue — as well as their levels of fats, cholesterol, triglyceride, leptin, and adiponectin.

Read: Scientists Plan To Maximize The Health Benefits Of Sweet Potatoes

Findings revealed that the mice given SPP had significantly lower body weight and liver mass. The creatures also had lower cholesterol and triglycerides, and higher levels of leptin and adiponectin. This suggests that SPP helps activate appetite suppression and control lipid metabolism in mice fed high-fat diets.

"We throw out huge volumes of wastewater that contains sweet potato proteins — we hypothesized that these could affect body weight, fat tissue and other factors," explained Dr. Koji Ishiguro from the National Agriculture and Food Research Organization in Japan, according to the statement. "Finding alternative uses for the sweet potato proteins in wastewater could be good for the environment and industry, and also potentially for health.”

Source: Ishiguro K, Kurata R, Shimada Y, Sameshima Y, Kume T. Effects of a sweetpotato protein digest on lipid metabolism in mice administered a high-fat diet. Heliyon. 2016.

Read more:

Sweet Potato vs. Regular Potato: Which Is Better For Your Health?

Women Who Eat A Lot Of Potatoes More Likely To Develop Gestational Diabetes, Study Finds