Australian researchers have found that eating a high-fat, high-carbohydrate diet may cause damage to cartilage in the knee and other joints.

Eating fatty foods could be more damaging to the cartilage in your knees and other joints than everyday wear and tear caused by walking and other exercise, Australian researchers say.

Cartilage, which acts as a shock absorber for joints, is often damaged as a result of normal wear and ageing, causing joint pain and stiffness associated with osteoarthritis.

A study by Queensland researchers has found that rats were more likely to develop osteoarthritis in the knee when fed a diet high in carbohydrates and saturated fatty acids like those found in foods including butter, meat and palm oil.

"Saturated fatty acid deposits in the cartilage change its metabolism and weaken the cartilage, making it more prone to damage," said researcher Professor Yin Xiao, of Queensland University of Technology's Institute of Health and Biomedical Innovation.

"Our findings suggest it's not wear and tear but diet that has a lot to do with the onset of osteoarthritis."

Obesity is a major risk factor for osteoarthritis, with the extra kilos carried putting increased pressure on joints including the knee.

The scientists from QUT and the University of Southern Queensland discovered changes in the cartilage of rats who ate a high-fat, high-carbohydrate diet reduced its ability to provide a cushioning effect for bones and joints.

During the study, the rats were given either a corn starch diet or one made up of simple carbohydrates and 20 per cent saturated fatty acids or beef tallow for 16 weeks.

Rats who ate the beef tallow or the saturated fatty acids ended up with damaged cartilage and bone changes similar to osteoarthritis.

However when the beef tallow was replaced with lauric acid, a saturated fatty acid found in coconut oil, there was less damage to the cartilage.

The researchers said further human clinical trials were needed to determine whether the replacement of some saturated fatty acids in people's diets with lauric acid could reduce the effects of osteoarthritis or even reverse it.

Their study was published on Tuesday in the journal Scientific Reports.