Does green coffee bean help people lose weight? That’s a question a lot of people are asking since seeing this weight loss supplement on the Dr Oz show. If you’ve been wondering about this also -or wondering if it’s a scam – let me try to help you make sense of things by looking at the green coffee bean weight loss research. I believe that only by reviewing it according to its research can we cut through the hype that permeates most websites and magazines about this product.
What is Green Coffee Bean?
Green coffee beans are coffee beans that have not been roasted. Roasting green coffee beans not only changes the color of the coffee beans but also removes a compound called chlorogenic acid. It’s chlorogenic acid that is at the heart of green coffee bean weight loss claims. Roasted coffee beans have little chlorogenic acid .
When supplements contain “green coffee bean extract”. chlorogenic acid is the extract they are referring to. Like many plant chemicals, chlorogenic acid also has antioxidant properties. Another extract of green coffee beans that is probably also used in supplements is caffeine .
Green Coffee Bean and Weight Loss
There is research on green coffee beans and weight loss. Below are summaries of some of those studies.
In a mouse study published in 2006 titled
Inhibitory effect of green coffee bean extract on fat accumulation and body weight gain in mice researchers noted that a green coffee bean extract (dosage used was 200 and 400 mg/kg body weight) reduced blood triglyceride levels.
However, the researchers also noted that neither chlorogenic acid or caffeine by itself was successful at reducing total body weight gain or fat accumulation in the belly.
A lot of the green coffee bean research out there involves mice.
A meta analysis looks at previous research and tries to lump all similar studies all together —using statistics— to see if, taken as a whole, a common trend or out outcome can be determined. In this case, the meta analysis was trying to see if there was enough evidence to say “Yes, green coffee bean extract help people lose weight. “
This meta analysis only included the best quality studies – randomized, placebo controlled double blinded clinical studies using overweight humans.
Of over 2000 studies that were found, only 3 studies met the criteria of the researchers. These 3 studies used a total of 143 people.
These were the 3 studies that were included:
Taken as a whole, these 3 studies appear to show that overweight people who use green coffee bean extract have significantly greater weight loss than people who used a placebo. That’s good, but the researchers went on to say that the degree of this effect was “moderate ” and that the “clinical relevance is therefore not certain.” The researchers go in to say that “the size of the [weight loss] effect is small.”
In other words, green coffee bean seems promote some weight loss but because of the lack of good studies, it’s hard to tell for sure if it really does work—and if it does work, people might only see small changes in weight.
All that said, these conclusions might change if researchers would do more—and better—studies.
So, this was a pretty small study. This was an investigation of a green coffee bean supplement called “GCA” made by Applied Food Sciences who funded the study. All subjects received the same treatments (for 6 weeks each) in a double blinded, random order. The treatments were:
- Placebo (not specified) given 3x per day
- 350 mg GCA taken 3x per day (1050 mg total)
- 350 mg GCA taken 2x per day (700 mg total)
A period of 2 weeks separated treatments to let the compounds wash out of the body.
As an aside, I noticed that Applied Food Sciences is based in Texas. With all of the universities and labs in America, why did they go to India to test their product? As a rule, I am usually skeptical of studies conducted in India.
At the end of the study:
- When used for 6 weeks, people lost about 2 kg (about 4 lbs) when taking 1050 mg of green coffee bean extract and about 1.5 kg (about 3 lbs) when using 700 mg of the extract. Both of these were deemed statistically significant (that’s good).
- A decrease in body fat by about 1% as well as Body Mass Index was also seen in both the 1050mg and 700 mg doses. Both values were deemed statistically significant.
Update: 3/24/14. I have always suspected there were problems with this study. I just could not get over why a company based in Texas would go to India to get testing done? Today, as reported by CBS News, this 2012 study has been retracted (taken back) as the researchers stated that they could not verify the results of the study. It turned out that researchers in India did the actual data collection in the study -not
the researchers whose names appeared on the paper. For more on this see these links:
In a 2014, there was a study titled Lipolytic activity of svetol®, a decaffeinated green coffee bean extract. This was a study of human fat cells. Basically fat cells were incubated in green coffee bean extract (the product was Svetol ) for between 2 horus and 8 days to see if the extract help release fat stores. This study noted that short term (2 hr) fat loss might be due to “residual caffeine traces” (odd since Svetol is said to be decaffeinated), long term (8 day) fat release was not due to caffeine but rather was attributed to Svetol.
While this is interesting, it is basically just a test tube study. Also, for those who are curious, the lead researcher of this study has an association with a supplement company that makes green coffee extract supplements.
How Does It Work?
The research so far tends to say that chlorogenic acid (an extract in green coffee bean) disrupts an enzyme called glucose-6-phosphatase. which is involved in how the body used glucose (sugar). I think things might be more complicated than this so I will leave the question of “how it works” to others.
How Much Works?
The 2011 meta analysis of green coffee bean already mentioned, states that ” The effective dosage of GCE (green coffee extract) for use as a weight loss supplement is also not established.” In other words, if green coffee bean does help weight loss, the amount that works is not known.
The reason we don’t know is because there are not enough good studies yet on green coffee extract and weight loss.
If the results of the 2012 green coffee bean study are taken as gospel, then people should look for products having at least 700 mg. Because the 2012 study only had 16 people. I’d like to see at least one larger study duplicating this before I feel confident in its findings.
Green Coffee Bean Side Effects
No study that I saw noted any significant side effects of green coffee bean. This does not mean that all green coffee bean supplements are side effect free however, because weight loss product makers sometimes combine different ingredients together to increase the weight loss effect.
Always look at the back labels of the weight loss supplements you use to see the list of ingredients they contain. If the research is to be believed, only green coffee bean extract should be needed. nothing else needs
I also recommend people investigate the companies whose products they use to make sure you are only getting green coffee bean extract. I say this because in this 2011 case report,tiled Adverse drug reactions of a slimming product contaminated with sibutramine. a green coffee bean supplement was found to be spiked with an illegal weight loss drug called sibutramine .
Sibutramine (also known as Meridia) was removed from the US market because it’s been linked to heart attacks and strokes.
As an aside I’ve seen sibutramine showing up in several “bee pollen weight loss pills.” For more on this see my reviews of Zi Xiu Tang a nd Slim Trim U among others on this site.
Also, as far as I can tell, all the human green coffee studies conducted to date have used “healthy people.” I am not aware of any study that has tested green coffee bean supplements in people with health problems or who take various medications. To be safe, those with health conditions should speak to their doctor or pharmacist.
One rat study noted that green coffee extract lowered blood pressure . Whether this applies to people or not needs better research. Those taking medications for high blood pressure should consult their doctor.
If the green coffee bean product also contains caffeine or other stimulants, this might alter blood sugar levels. This might be a problem for some diabetics.
A small study from 2001 published in the American Journal of Clinical Nutrition. noted that high doses (2 grams) of chlorogenic acid increased homocysteine levels in men and women. While controversial, homocyestine elevation may play a role in heart disease.
It is unknown if green coffee bean supplements raise homocysteine. People with heart disease who take green coffee bean supplements should speak to their doctor about their homocysteine levels first, just to be safe.
Does Green Coffee Bean Work?
There is no doubt that green coffee bean has some weight loss research. There is also no doubt that the weight loss proof is a lot less than what most websites tell you, with most of the evidence stemming from lab mouse research. For those who are curious, as far as I could tell, the product called Svetol. appears to be one of the few supplement’s that had at least some human clinical evidence. While I remain somewhat skeptical, if the human weight loss research conducted so far is to believed, green coffee bean might help people lose a little weight, but until better research is conducted, it’s hard to say for sure.
What do you think?