While past studies have shown coffee in moderation could help you lose weight and cut risk of type 2 diabetes, a recent examination found that the opposite—coffee overload — could prevent weight loss.

Researchers from the Western Australian Institute for Medical Research (WAIMR) and the University of Western Australia's School of Medicine and Pharmacology published their findings in the Journal of Agricultural and Food Chemistry. The researchers discovered that excess consumption of certain polyphenols called chlorogenic acid (CGA) found in coffee could have health implications, from preventing fat loss to developing insulin resistance.

"Everybody knows about the effects of caffeine, but when we're considering our lifestyle choices it's important to remember that compounds such as CGA can have an effect on our health if they're not consumed in moderation," said Vance Matthews, assistant professor at WAIMR. Matthews and Kevin Croft, professor at Western Australia, led the study that tested CGA's effects on obese mice that were given different doses of the compound.

The mice that were given doses equivalent to five or six cups of coffee per day showed retention of fat within cells, meaning they were stocking up in fat. The obese mice also showed more glucose intolerance, a pre-diabetic condition, and increased resistance to insulin regulation. However, the authors say that it is still safe to drink coffee in moderation to reduce blood pressure and the accumulation of fat, as past studies have demonstrated.

"It seems that the health effects are dose-dependent," Matthews said. "A moderate intake of coffee, up to three to four cups a day still seems to decrease the risk of developing diseases such as cardiovascular disease and type 2 diabetes."

But researchers also found that CGA, which is also found in tea and fruits such as plums, didn't stop the obese mice from gaining weight questioning the effectiveness of weight loss supplements that contain CGA.

"People might be wasting their money if they're buying expensive products like green coffee bean dietary supplements which are currently considered to be amazing weight loss products," Croft said.

The popular brew is widely known to protect the brain as you age. Coffee drinkers have cut their risks of Alzheimer's and dementia by 60 percent, according to a study published in the European Journal of Neurology, while lowering risk of Parkinson's by 32 to 60 percent.

Source: A Mubarak, JM Hodgson, MJ Considine, et al. Supplementation of a high-fat diet with chlorogenic acid is associated with insulin resistance and hepatic lipid accumulation in mice. Journal of Agricultural and Food Chemistry. 2013.