Sweet potatoes are not just delicious and healthy sources of low-fiber carbohydrates, they can also help you shed some pounds according to Japanese researchers.

New research published in the journal Heliyon suggests that drinking the waste water from boiling sweet potatoes can help you lose weight and improve your digestion.

Dr. Koji Ishiguro and his team from the National Agriculture and Food Research Organization in Japan were looking for ways to make use of the waste water from cooking sweet potatoes which is why they arrived at testing its dietary benefits and nutritional value.

Experts found that the wastewater contains protein that can suppress the appetite in mice and that it could also work the same way for humans.

In their study with mice, they found that the animals had significantly lower body weight after they were given high levels of sweet potato peptide (SPP) - the substance produced in the water during the boiling process.

Lead researcher Dr Koji Ishiguro said: "We throw out huge volumes of waste water that contains sweet potato proteins.

"We hypothesised that these could affect body weight, fat tissue and other factors.

In Japan, 15 percent of sweet potato is used in the production of products that rely on starch, and some processed foods. Because of this, a large amount of waste water is discarded in rivers and oceans which can lead to environmental problems. Dr. Ishuguro also added that saving the wastewater from sweet potato will not only be helpful to the environment and the industry, but also offers wonderful benefits to human health.

"We were surprised that SPP reduced the levels of fat molecules in the mice and that it appears to be involved controlling appetite suppression molecules. He concluded.

"These results are very promising, providing new options for using this wastewater instead of discarding it."