Are Green Coffee Beans Effective?
How Green Coffee Beans Work And Why They May Not Be Necessary
October 24th, 2012By Brian Rigby, Clinical Nutrition Writer
Green coffee bean extract has enjoyed an explosion in popularity recently due to its purported benefits for weight loss. Does it actually work though, and if so, how?
What Are Green Coffee Beans?
First, a little background on what "green coffee beans" actually are. Green coffee beans (GCBs) aren't a special variety of regular coffee beans, but rather are the raw, unroasted coffee bean (i.e., the unprocessed, unadulterated bean). This is important because the weight-loss benefits of GCBs can be attributed to a few compounds which are mostly destroyed in the process of roasting coffee.
While GCBs from certain areas may contain increased levels of these important compounds, it ultimately does not matter as any decent company selling a GCB extract will normalize the levels of the extracted compounds.
What Makes Green Coffee Beans Potentially Effective?
Coffee beans contain a number of phytochemicals, but the ones attracting the most attention all belong to a group of compounds called "Hydroxycinnamic Acids". Of the hydroxycinnamic acids found in coffee beans, the most potent one appears to be chlorogenic acid.
Chlorogenic acid and other hyroxycinnamic acids are not limited to the coffee plant, as it turns out. You can actually enjoy them from a variety of foods, most importantly blueberries and sunflower seeds, but also apples and pears. While you may not get the same amount as from a GCB extract, you will have the benefit of all the rest of the beneficial phytochemicals found in these foods (like anthocyanins in blueberries).
Research is still preliminary as far as how chlorogenic acid effects its changes, but the research suggests that there may be a few mechanisms including:
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Preventing starch from being digested1
Preventing glucose from being absorbed1
Lowering the amount of fat our body synthesizes2
Increasing the amount of fat our body burns2
If confirmed, these effects would synergistically aid weight loss by reducing energy intake and improving energy metabolism, everything you could hope for when losing weight. The key word here is 'confirmed', though--very little research has actually been done (on humans or otherwise) in regards to GCBs and chlorogenic acid.2
The research which has been done is promising--weight loss increased significantly (3-5 lbs. more than the placebo).3 Unfortunately, these same studies have all had very small sample sizes (the largest had only 67 participants) which means their results cannot be determined to be conclusive. Before any serious conclusions can be drawn, more and larger studies must be performed.
What About Tea?
Tea does not contain any chlorogenic acid, despite what some other articles may report (the confusion stems from a study which measured the effects of weight loss when a combination of black tea and chlorogenic acid were consumed--the chlorogenic acid was supplemented, not a part of the tea). Instead, green tea contains other useful compounds for weight loss.
The most important compound green tea contains (and only green tea--the oxidation process to make black tea destroys it) is a phytochemical with the rather imposing name "Epigallocatechin Gallate", thankfully shortened to "EGCG". EGCG, like chlorogenic acid, has been shown to increase the rate at which we burn fat and also improved serum lipid levels (lower cholesterol and triglycerides).4 It did not, however, affect carbohydrate metabolism in the same way the GCBs do.
To gain the anti-obesity effect of green tea, approximately 500 to 1000 mL must be consumed daily, or 2 to 4 cups.
Eat Your Fruits And Vegetables!
Green Coffee Bean extract shows promise, but it may be less effective than changing your diet to increase intake of fruits and vegetables. In the average American's diet, coffee is the #1 source of antioxidants. This isn't because coffee is a beverage astoundingly rich in phytochemicals and beneficial substances (as mentioned earlier, the roasting process destroys the majority of them), it's because the average American's diet is basically devoid of antioxidants and phytochemicals from much richer sources like fresh fruits and vegetables!
While an effect can be seen from the studies which have been done on GCBs, it's questionable whether or not the same effect would be noticed in a group of people who ate significant amounts of fruits and vegetables and thus had a significant intake of phytochemicals, many of which improve energy metabolism.
Phytochemicals have more potential benefits than weight loss, as well--many are anti-inflammatory, improve blood lipid profiles, exert anti-carcinogenic effects, and overall increase health in a plethora of ways. GCB extract, on the other hand, only exert the weight-loss benefit.
Summing It All Up
Overall, if you are looking to lose weight, your absolute first step should be to increase the amounts of fruits and vegetables in your diet thereby increasing your intake of powerfully beneficial phytochemicals.
A second recommendation, if you drink coffee, would be to switch to green tea, which is more likely to affect weight loss.
If, after these changes have been made, you are still looking to increase weight loss, then green coffee bean extract could be an effective tool--just don't rely on it alone to provide you with results. Take charge of your health and increase your phytochemical load with fresh fruits, vegetables, and spices!
Key Points
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More research needs to be done to conclusively determine if green coffee beans are effective for weight loss.
Green tea has also been shown to be an effective weight-loss aid (ergogenic aid).
Chlorogenic acid (the active compound in green coffee beans) is also found in blueberries, sunflower seeds, apples, and pears.
Increasing fruit and vegetable intake may exert as powerful a benefit on weight loss as green coffee beans.
Fruits and vegetables contain many beneficial phytochemicals which will improve your health above and beyond weight loss.
References
1. Thom E. The effect of chlorogenic acid enriched coffee on glucose absorption in healthy volunteers and its effect on body mass when used long-term in overweight and obese people. J Int Med Res. November-December 2007;35:900-8.
2. Onakpoya I, Terry R, Ernst E. The Use of Green Coffee Extract as a Weight Loss Supplement: A Systematic Review and Meta-Analysis of Randomised Clinical Trials. Gastroenterol Res Pract. August 2010;2011: 382852. doi: 10.1155/2011/382852.
3. Vinson JA, Burnham BR, Nagendran MV. Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects. Diabetes Metab Syndr Obes. January 2012;5:21-7. doi: 10.2147/DMSO.S27665.
4. Basu A, Sanchez K, Leyva MJ, et al. Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome. J Am Coll Nutr. February 2010;29:31-40.
