While dieting and exercise certainly help people to lose weight, there are some cases where those approaches just aren't enough on their own. There could now be a new source of hope, however, as scientists have discovered that clay may cause ingested fat to pass right through the body.

University of South Australia PhD candidate Tahnee Dening made the initial discovery, when she was investigating the ability of clay particles to improve the oral delivery and absorption of antipsychotic drugs in lab animals. What she found was that although the particles weren't breaking down to release a payload of medication, they were attracting and then soaking up fat droplets.

"Not only were the clay materials trapping the fats within their particle structure, but they were also preventing them from being absorbed by the body, ensuring that fat simply passed through the digestive system," she says. "It's this unique behaviour that immediately signalled we could be onto something significant – potentially a cure for obesity."

Dening and colleagues proceeded to conduct an experiment in which four groups of lab rats were put on a high-fat diet. One group was also fed dried particles of natural montmorillonite clay, the second group received synthetic laponite clay, the third batch were given a leading weight-loss drug known as orlistat, and the fourth group served as a control, receiving nothing other than the high-fat food.

After two weeks, the two groups of clay-eating rats and the orlistat-taking rats had all lost weight, with the animals that consumed the clay actually losing a bit more. Additionally, the rats from the clay groups exhibited no side effects. By contrast, because orlistat works by blocking digestive enzymes, it can cause side effects such as stomach aches, bloating, flatulence and diarrhea.

"What we're researching now is a synergistic approach with both the clay material and orlistat: the orlistat blocks the enzyme that digests fat molecules, and the clay particles trap these fats so they're excreted out of the body without causing gastrointestinal disturbances," says Dening. "We're essentially attacking fat digestion and absorption in two different ways and we hope this will lead to greater weight loss with fewer side effects."

It is hoped that human trials may begin soon. A paper on the research was recently published in the journal BMC Biomedical Engineering.