Lessons from the dubious rise and inevitable fall of green coffee beans


News this week that a randomized controlled trial of green coffee bean (GCB) has been officially retracted from the medical literature signals what is hopefully the end to one of the most questionable diet products to appear on the market in years. Plucked from obscurity and then subjected to bogus research, it’s now clear that the only people that actually benefited from GCB were those that profited from its sale. GCB had some powerful boosters, too. Once it became one of Dr. Oz’s “miracle” weight loss cures, sales exploded following two hype-filled episodes. Oz even did a made-for TV clinical trial with GCB, ignoring the requirements for researchers to obtain ethical approvals before conducting human subject research. Oz’s promotion of GCB was so breathless and detached from the actual evidence that his actions were subsequently eviscerated by Senator Clair McCaskill during televised hearings on weight loss scams. It’s a long, sordid, ugly and yet entirely predictable story.

Green coffee bean wasn’t the first miracle weight loss treatment, and I’m certain it won’t be the last. As long as there is an obesity problem, there will those that promote quick fixes and snake oil to treat it. These treatments exist because reality is hard to accept: permanent weight loss is difficult. We all know obesity is a Bad Thing, yet its prevalence continues to grow. As obesity rates rise, so do cases of diabetes, heart disease, and even cancer. Short of quitting smoking, there are few things you can do for your health with as much benefit as maintaining a healthy weight. Given how widespread obesity is, and how difficult it is to fix permanently, it’s not surprising that weight loss cures are fodder to those that want to sell magical cures. And when it comes to promoting quick fixes, there is no platform better than one you can get from being profiled on The Dr. Oz Show.

The story of GCB can’t be told without describing the pivotal role played by Dr. Mehmet Oz. If you’re trying to sell a product, yet you don’t have actual scientific evidence to back up your claims, The Dr. Oz Show is the best platform on television. There is no other show that can top The Dr. Oz Show for the sheer magnitude of bad health advice it consistently offers, all while giving everything a veneer of credibility. That’s because Dr. Oz is a real physician – he just doesn’t play one on television. That might surprise you given his show’s content. He’s promoted homeopathy and faith healing. He’s hosted supplement marketer Joe Mercola to promote unproven supplements, and the notorious “Health Ranger”, antivaccinationist and conspiracy theorist Mike Adams. Oz has promoted ridiculous diet plans, and he gives bad advice to diabetics. Then add the long list of “miracle” foods like red palm oil, or manufactured public health scares like cell phones causing breast cancer. “The Dr. Oz Effect” was coined to describe how Oz drives product sales, but it more accurately describes how Oz’s advice wastes the time and finances of consumers that actually follow the advice he offers.

The dubious trial that convinced Dr. Oz

Dr. Oz’s first episode on GCB looked at the Vinson trial. Even taking the paper at face value (before there was any evidence of fraud), the results were questionable, as I noted when I actually read the study:

  • The study was published in an obscure journal that accepted the paper after 12 days, a period which apparently included peer review
  • The trial was never registered at, which is an expectation for credible clinical trials
  • The authors had no particular history of research in this area. The lead author was a chemist in Pennsylvania
  • The trial was funded by a supplement manufacturer
  • The trial was made up of just 16 patients and lasted 12 weeks only
  • There was no detail in the paper on how patients were recruited, or if inclusion and exclusion criteria were applied
  • How body mass index (BMI) was measured wasn’t disclosed
  • There was no evidence of research ethics board (institutional review board) approval of the trial
  • The randomization process wasn’t described
  • How the doses were calculated wasn’t described
  • While the trial was called “blinded”, it actually wasn’t, as the design made it easy for patients to figure out if they were receiving GCB or placebo
  • Some patients lost as much weight while taking placebo as they did taking GCB. There was no clear GCB effect
  • There was no tabulation or reporting of side effects

All we could conclude from the Vinson trial was that it was poorly conducted, sloppily written and provided unimpressive and clinically-useless results. There was no convincing evidence to suggest that GCB offered any meaningful benefit. As I noted in my conclusion at the time, GCB had all the features of a bogus weight loss product. It was implausible, and backed by flimsy evidence with some serious methodological issues. Even before we knew it was fraudulent, it was clear this trial should not be used to guide treatment decisions. None of this was an obstacle to Oz, who declared it to be the newest panacea for weight loss, using words like “magic”, “staggering”, “unprecedented”, “cure” and “miracle pill”. He concluded his episode with an absurd “trial” in two audience members who took the supplement for five days. One reported a two pound loss, the other, a six pound loss. In doing so he illustrated one of the worst ways to evaluate a weight loss supplement: short duration of use and informed by anecdotes. It served as nothing more than an extended advertisement for the product.

Part 2: Dr. Oz doubles down on green coffee bean with his own bogus trial

In a hamfisted attempt to address the criticism of Oz’s first episode on GCB, Dr. Oz revisited the topic in a follow-up episode, which he called The Green Coffee Bean Project (Oz has scrubbed the episode’s notes from his website now, but the internet never forgets.) It’s not surprising. Based on the Vinson study, Oz designed and conducted a clinical trial of green coffee bean on his studio audience. He gave what appeared to be about 100 women either GCB or placebo for two weeks. Oz noted that the group taking the green coffee bean extract group lost 81.5 pounds collectively, while the placebo group lost 42 pounds. Assuming 50 participants per group, that’s 1.6lbs in the green coffee bean group, and 0.84 pounds in the placebo group. You can review the whole list of problems with this trial in my prior post, but what’s more concerning to me was that Oz didn’t obtain ethical approval to conduct the trial. (Oz subsequently admitted this in later Senate testimony.) How this could be acceptable to Columbia University, where he still practices as a surgeon, is incredible, yet perhaps reflects another aspect of The Dr. Oz Effect: Daytime TV trumps research ethics.

If Oz’s first episode was a mockery of looking at the evidence, the second episode was a mockery of how we generate evidence. Oz is a published research scientist. He knows how to do proper research. This wasn’t even close. His made-for-TV trial delivered only one thing: more accolades and praise from Oz about a product that still lacked any convincing evidence of benefit.

Dr. Oz and the Terrible, Horrible, No Good, Very Bad Day

When Dr. Oz arrived to speak at Senate hearing into weight loss scams in hearings led by Senator Clair McCaskill, he probably wasn’t expecting to be verbally disemboweled on television. McCaskill called him out for his breathless hyperbole, drawing attention (among all of Oz’s “miracles”) to green coffee bean:

Dr. Oz: Well, if I could disagree about whether they work or not, and I’ll move on to the issue of the words that I used. And just with regards to whether they work or not, take green coffee bean extract as an example. Uh, I’m not gonna argue that it would pass FDA muster if it was a pharmaceutical drug seeking approval, but among the natural products that are out there, this is a product that has several clinical trials. There was one large one, a very good quality one, that was done the year that we talked about this, in 2012. Listen, I’ve…

Sen. McCaskill: wh..wha..I wanna know about that clinical trial. Because the only one I know was sixteen people in India that was paid for by the company that, that was in fact, at the point in time when you initially talked about this being a miracle, the only study that was out there was the one with sixteen people in India that was written up by somebody that was being paid by the company that was producing it.

McCaskill got the evidence exactly right. There was still only a single trial (Vinson) with sixteen people studied. Yet the Oz Effect had driven a massive demand for GCB. And yet Oz was hardly apologetic, and described himself as a victim, rather than the cause of the problem. What was clear from his testimony is that when it comes to facts versus infotainment, television wins, every time:

Dr. Oz: I actually do personally believe in the items I talk about in the show. I passionately study them. I recognize that often times they don’t have the scientific muster to present as fact, but nevertheless, I would give my audience the advice I give my family all the time, and I have given my family these products.

Emphasis added. If you haven’t watched the hearings yet, the best and smartest summary on Oz and supplements in general came from John Oliver.

The Federal Trade Commission gets involved

In May of this year, the FTC announced it was suing a Florida-based company (Applied Food Sciences) for its promotion of green coffee bean. The vendor established web sites that made unsubstantiated claims about green coffee bean, while linking to clips and images of The Dr. Oz Show. In September, the FTC announced it had a deal and settlement from Applied Food Sciences (AFS) and it was a bombshell. Not only was the advertising misleading, but the trial itself was fraudulent:

The FTC charges that the study’s 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. When the lead investigator was unable to get the study published, the FTC says that AFS hired researchers Joe Vinson and Bryan Burnham at the University of Scranton to rewrite it. Despite receiving conflicting data, Vinson, Burnham, and AFS never verified the authenticity of the information used in the study, according to the complaint.

Despite the study’s flaws, AFS used it to falsely claim that GCA caused consumers to lose 17.7 pounds, 10.5 percent of body weight, and 16 percent of body fat with or without diet and exercise, in 22 weeks, the complaint alleges.

Although AFS played no part in featuring its study on The Dr. Oz Show, it took advantage of the publicity afterwards by issuing a press release highlighting the show. The release claimed that study subjects lost weight “without diet or exercise,” even though subjects in the study were instructed to restrict their diet and increase their exercise, the FTC contends.

The FTC complaint really needs to be read to be believed. During the “revisions” to the manuscript, the following appears to have been changed:

  • The trial went from being described as open label to double-blind, placebo controlled
  • The duration of the study grew from 20 weeks, to 24 weeks, and then to 28 weeks
  • Six of the sixteen final weights were restated

Vinson and Burnham, the two authors hired by AFS to be the “authors” of the paper, never actually reviewed the raw data for the trial. Despite the repeated restatements of data, they subsequently finalized and signed off on a manuscript and found a journal willing to publish the results. Add the Dr. Oz effect, and AFS subsequently sold 500,000 bottles, apparently at $50 each. And that’s how a chemist and psychologist in Pennsylvania came to be the authors of a bogus clinical trial of green coffee bean, driving millions of dollars in sales for AFS.

The retraction

In light of the FTC’s findings, it was just a matter of time before there would be pressure to retract the study. And it happened this week. In a terse one-sentence retraction highlighted by Retraction Watch, Vinson and Burnham have now retracted the paper:

The sponsors of the study cannot assure the validity of the data so we, Joe Vinson and Bryan Burnham, are retracting the paper.

In an amazing display of handwaving and fingerpointing, the two hired “authors” are now blaming the sponsor for the validity of the data. No apologies for the serious ethical lapse of pasting their names on research they didn’t even conduct. And yet they blame the sponsor, who was the manufacturer, who should be last group with any involvement in the data collection and analysis.

What have we learned

The retraction of the Vinson trial has been cited by some as damaging Oz’s credibility. I frankly don’t think Oz had any credibility to lose. Even at face value, the evidence was never there and should never have been promoted by Oz as a treatment. Yes, admittedly that’s the case for almost everything Oz seems to promote on his show. Yes, the green coffee bean paper was fraudulent – but the fraud was so incompetent, they couldn’t even make the fake results look impressive, or make the study look credible. Even the fake data wasn’t impressive enough to justify the hype and hyperbole. Yet there seems to be no stopping Dr. Oz. The miracles continue, even after his Senate smackdown. I’m heartened by medical students like Benjamin Mazer, who is determined to go after Dr. Oz by asking his medical regulator to take action against him. Is the Dr. Oz strong enough to deflect a regulator? Time will tell.

Avoiding the next green coffee bean

One of the most frustrating aspects of the green coffee bean is the underlying fact that there simply are no magical pills or panaceas for weight loss. None. So how does one avoid the next miracle cure? It’s what Dr. Oz actually admitted to under Senate questioning: There are no miracle pills that replace a proper diet that includes calorie restriction. The facts of weight loss aren’t catchy, but they are based in reality, not hype. I covered many of them in my review of Yoni Freedhoff’s The Diet Fix:

The laws of thermodynamics hold. To lose weight you must expend more calories than you consume. For practical purposes, you must focus on the consumption side because…

You can’t outrun a bad diet. Calories are simply too easy to come by, and food is too calorie dense, to not restrict your diet. The most effective way to do so is to…

Track your calories consumed. Calorie tracking and journaling is highly correlated with more successful, permanent weight loss. This strategy works because…

The best diet is one you can sustain permanently. You don’t need to demonize any food groups. Temporary changes give temporary results. Permanent weight loss must be accompanied by permanent change. Quick fixes in the form of pills and potions are unnecessary, because…

Supplements, by and large, are useless. Even the most effective weight loss products (that are prescription drugs) provide only modest incremental benefit. In most cases, the benefit from supplements (or prescription drugs) is questionable.


Green coffee bean would probably be a fringe supplement if it wasn’t for a supplement company that decided to buy its own “evidence”. Once the Vinson trial was published, the Dr. Oz Effect pushed green coffee bean from nothing into a supplement blockbuster. Yet the entire trajectory was entirely predictable. Green coffee bean wasn’t the first useless weight loss supplement, and it definitely won’t be the last. While you won’t hear it from Dr. Oz (unless he’s speaking in the Senate) there simply are no quick fixes and no weight loss “miracles”. Let’s hope everyone’s a little more skeptical when the next “miracle” appears.



Posted in: Clinical Trials, Health Fraud, Herbs & Supplements, Science and the Media

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