The Green Coffee Bean Problem

When I want to reinforce the need for critical thinking, I sometimes bring up the green coffee bean problem.

In 2012, a research article entitled “Randomized, Double-Blind, Placebo-Controlled, Linear Dose, Crossover Study to Evaluate the Efficacy and Safety of a Green Coffee Bean Extract in Overweight Subjects” was published in the seemingly reputable journal Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy. The subjects received a high dose of chlorogenic acids found in green coffee extract, purported to influence glucose and fat metabolism. The reported results were incredible: the subjects lost 10% of their body weight and 16% of body fat in 22 weeks – without any dieting or exercise.

Green coffee beans took the dieting world by storm. Dr. Oz used words like “magical,” “staggering,” and “unprecedented discovery.” Not surprisingly, sales soared.

But there was a problem with the green coffee bean approach to weight loss. Actually, many problems.

To start, the Food and Drug Administration (FDA) recommends weight-loss studies last at least 12 months and include at least 3,000 participants who receive the medication and at least 1,500 who receive a placebo. This study covered 22 weeks and 16 subjects (8 and 8).

Another issue is that the authors of the paper were University of Scranton chemistry professors who had no medical experience, nor had they previously published any other research on weight loss. In fact, the study was conducted by different researchers in India and funded by a supplement manufacturer.

Even the journal the research was published in seems suspect. The journal says it’s a peer-reviewed publication, but claims an average of 12 days from submission to editorial decision including peer review. That’s not much of a review.

The above three flaws should be enough red flags for most people to wonder about the research. But it’s even worse. According to one careful analysis:

• It’s not a double-blind study, despite claiming to be
• Some subjects lost as much weight on the placebo as the supplement
• Diet and exercise were not actually tracked by the study
• … and much more.

The article was retracted from the journal after the Federal Trade Commission (FTC) reported the lead investigator “repeatedly altered the weights and other key measurements of the subjects, changed the length of the trial, and misstated which subjects were taking the placebo or GCA during the trial.” The FTC ordered the supplement manufacturer who funded the study to pay a $3.5M fine.

Yes, deep critical thinking is time-consuming and difficult. But often we don’t even do a cursory inspection of claims. Hundreds of thousands of people were tricked by a research study that only involved 16 people and lost millions of dollars.

That’s the green coffee bean problem.