Try Drinking Waste Water from Cooking Sweet Potatoes to Lose Weight, Researchers Say

There’s a lot to be said for sweet potatoes when it comes to improving your health. The fiber helps fill you up, while the nutrients help you stay healthier. The carotenoids, which give the sweet potatoes the orange color, convert to vitamin A for the body and provide antioxidants and anti-aging capabilities.

Sweet potatoes are also rich in B-1, B-2, B-3, riboflavin, and niacin, besides containing some B-5 and B-6. These vitamins help the body change food to an energy source.

While the sweet potato is good for your health, there’s also a significant use of the water left over after the sweet potato cooked. In fact, according to an article published in “Heliyon,” it may have a benefit to digestion, while also aiding in weight loss.

Researchers from Japan at the National Agriculture and Food Research Organization were studying ways to use the wastewater left over from cooking sweet potatoes at the industrial level since massive amounts are thrown out every year. They started with the potential nutritional values but moved on to the effect on dietary intake.

Japanese researchers found proteins in the starchy water suppress appetite
It contains sweet potato peptide which is produced during the boiling process
After 28 days, mice fed high levels of the protein were found to have lost weight
Experts say the results could be replicated in humans

The researchers used the protein that is found in the water after boiling sweet potatoes and tested the effect it had on mice given high-fat diets by feeding one group high levels of the sweet potato peptide protein…SPP… and another group of mice receiving a much lower level of it. A third group in the study received no SPP.

To their amazement, after a 28 regimen, the group that had the highest concentration had lower cholesterol and triglyceride levels. They also had higher levels of the hormones called leptin and adiponectin.


These two hormones not only play a role in obesity, but they also help regulate the body’s metabolism and have an important role in metabolic syndromes.

Basically, the SPP found in the water after cooking sweet potatoes helped lower the appetite of the mice and control the fat metabolism. The mice given the higher concentration weighed less.

Drinking the Leftover Water
Based on the findings, the group hypothesized that the waste water from sweet potatoes could have a positive effect on weight loss. While the study was initially started to find ways to use this water, rather than polluting the environment with it, it may have a tremendous potential for helping people with weight problems or even metabolic diseases.


While the study involved mice and not people, mice are very similar to humans biologically. It’s just the start of the research necessary to identify whether this would be beneficial to people and how to create a functional food material to use from the waste product.

Does this Mean you should Save the Sweet Potato Water and Add it to your Diet?
Until more studies are out, there’s no verdict as to whether it will help. What is known is that sweet potatoes are healthy foods that can fill you up. They keep your carbohydrate hunger in check without adding hundreds of calories to your diet.

While a baked sweet potato may have more calories than a bowl of greens, it also helps fill you up and is lower in calories than a baked potato by approximately 42 calories. That can be a substantial saving if substituted over the long term.

Whether the water helps humans lose weight is yet to proven. In the meantime, you can’t go wrong nutritionally stocking up on these nutrient rich vegetables, as long as you don’t serve them with a pound of butter and marshmallows.

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

About the Author Calleigh

Calleigh is passionate about inspiring others to a healthy living and encourages to re-discover their lifestyle. Her keen interest in health shines through in her written work on DIY skin care, beauty tips, healthy and active lifestyles.

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