Although past studies have shown that drinking moderate amounts of coffee can help weight loss, the latest findings indicate that drinking too much could actually prevent weight loss.
Scientists at the Western Australian Institute for Medical Research (WAIMR) and the University of Western Australia's School of Medicine and Pharmacology found too much of a certain polyphenol found in coffee called Chlorogenic Acid (CGA) could thwart fat loss and lead to insulin resistance.
The study published in the Journal of Agricultural and Food Chemistry looked at more CGA affected obese mice. The mice in the experiments were given different doses of CGA, and mice given does equivalent to five or six cups of coffee per day showed retention of fat within cells. These mice also showed pre-diabetic symptoms like more glucose intolerance, and increased resistance to insulin regulation. "Studies have shown that coffee consumption lowers the risk of developing type 2 diabetes," co-researcher Professor Kevin Croft said in a news release. "This also included research on decaffeinated coffee, which suggested that the health benefits are from a compound in coffee apart from caffeine."
"With this in mind, we studied the effects of Polyphenols, or more specifically CGAs, which are very rich in coffee but also found in tea and some fruits including plums. The CGAs were previously known for their health benefits, increasing insulin sensitivity and reducing blood pressure and body fat accumulation," Croft added.
However, the new study reveals the opposite in dosages equivalent to five or six cups of coffee per day, according to researchers.
"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," co-author Vance Matthews, of the Western Australian Institute for Medical Research, said in a statement.
"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 study also found that CGA doesn't prevent weight gain in obese mice put on 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," Croft concluded.