Knocking back five cups of coffee per day may lead to weight gain and increase the risk of diabetes, researchers have warned.
While previous studies have shown coffee in moderation could help weight loss and actually reduce the risk of type 2 diabetes, these recent findings suggest that too much coffee could prevent weight loss.
Australian researchers found that over- consumption of certain polyphenols found in coffee called chlorogenic acid (CGA) could prevent fat loss and lead to insulin resistance.
The study, which was published in the Journal of Agricultural and Food Chemistry, tested CGA's effects on obese mice, which 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.
The obese mice also showed more glucose intolerance, a pre-diabetic condition, and increased resistance to insulin regulation.
'Studies have shown that coffee consumption lowers the risk of developing type 2 diabetes,' said study co-author Professor Kevin Croft, of the University of Western Australia
'This also included research on decaffeinated coffee, which suggested that the health benefits are from a compound in coffee apart from caffeine.
It seems that the health effects are dose-dependent. 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,' he said.
The researchers also found that CGA doesn't prevent weight gain in obese laboratory mice fed a high-fat diet when used at higher doses.
'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,' Professor Croft said.