The first headline blasted, “Slim by Chocolate!”, the next, “Eating Chocolate Can Help You Lose Weight – Really!”, and soon John Bohannon’s work was being touted amongst German, Indian, Australian and American news outlets. For most scientists – Bohannon is both a biologist and a scientific journalist based out of Harvard University – this sort of international coverage would be nothing short of delightful. Bohannon, however, knew that his fame was based on an inherently flawed study, one trumpeting a sweet, sweet lie.

In an open account for io9, Bohannon explains his motivation to deliberately spread bad science to the media at large. In December 2014, the scientist was approached by German filmmakers Peter Onneken and Diana Löbl, who sought to make a documentary film exposing the ease with which lousy nutritional science can be conducted and disseminated to the masses. Prior to the filmmakers’ call, Bohannon had successfully executed a hoax of his own, submitting a “credible but mundane scientific paper” to over 150 fee-charging open access journals in a “sting operation” for Science magazine. In Onneken and Löbl’s eyes, he was the right man for the job.

Given Bohannon’s previous connection with Science, to accomplish this new work, he swapped out his first name – John for Johannes – and made himself a titular figurehead as Research Director of the fictitious Institute of Diet and Health. Otherwise, for a fraudulent study, the group’s work was superficially quite legitimate. They recruited sixteen German subjects to participate in a randomized clinical trial and enlisted a doctor to oversee the subjects as well as a statistician to interpret the findings, both of whom were aware of the study’s deceitful nature.

Dr. Guther Frank, the hired general practitioner, ensured that all study participants were of sound health before designating them to one of three chocolate-2224998_1920dietary regimes: one group would adhere to a diet low in carbohydrates; the second group would follow the same low-carb diet, adding one dark chocolate bar per day to their regimen; and the third group, serving as the controls, would make no changes to their current diet. It was Frank’s suggestion that the study’s dietary supplement be dark chocolate, his rationale based solely on the popular belief that “bitter chocolate tastes bad, therefore it must be good for you.” The study lasted three weeks, ending much in the same way it started, with a series of questionnaires and blood tests. Overall, eighteen variables were measured for each of the sixteen study participants.

After the data was analyzed by an objective party, Bohannon, Onneken and Löbl poured over the results. The findings: both the groups who ate a low-carb diet lost close to 5 pounds over the 21-day experiment. The control group saw their pounds fluctuate, but the net weight loss result was nil. Moreover, the dieting group who incorporated dark chocolate into their daily regimen saw their pounds shed at a 10% faster rate, a statistically significant result. The chocolate group also fared better in terms of cholesterol level, and scored themselves higher on questionnaires pertaining to well-being.

Now for the study’s intrinsic flaws. A large number of variables collected from a small sample size is highly likely to produce an erroneous result. Equally, the control group’s diet was, by design, blatantly uncontrolled between study participants and not even questioned by researchers. The study’s first author was a phony scientist affiliated with a spurious institution. On top of all that, Bohannon himself admits in the paper that while the study recruited 5 male and 11 female subjects between the ages of 19-67, no measures were taken to ensure that the treatment groups were age- and sex-matched. This was fatally misleading work. More concerning is the fact that these intentional acts of scientific deceit were completely neglected during the checkpoints (peer review, for one) that normally demand a shrewd eye.

Bohannon completed the manuscript of the study’s findings, glossed with the catchy title, “Chocolate with high cocoa content as a weight-loss accelerator”, and sent it off to various publishers. Knowing that the paper’s flaws were plentiful, he shuttled his less-than-stellar science to 20 scholarly journals with equally shoddy reputations. Following submission, Bohannon, Onneken and Löbl received word no less than 24 hours later that their findings were accepted into several scientific journals without qualms. Two weeks after the round of initial acceptances, the article was published in International Archives of Medicine after very little scrutiny – no experiments were recommended at the hands of the publishers, nor was a word of Bohannon’s original manuscript changed. (Following Bohannon’s tell-all, the article was revoked).

Once the media got word of the group’s publication, thanks to Bohannon’s carefully crafted press release, the scientist was contacted by a slew of newsweight-loss-2036969_1920 outlets. When reporters got their time with Bohannon, they asked cursory questions related to the brand of chocolate used as the dietary intervention or simply fact-checked the spelling of his last name. No journalist seemed concerned about the study’s number of participants or about the magnitude of difference of weight loss between diet groups – neither of which were reported in the press release. Instead, the journalists devoured the bitter bait, blindly publishing this palatable finding for the public to indulge on.

In the end, seventeen media news outlets covered Bohannon’s hoax, spread as wide as the front-page of Bild, Europe’s largest daily newspaper. Caliber of the media sources aside, this deliberate exercise in disseminating deeply flawed research raises larger questions about the responsibility of the media to ensure proper scientific communication. In an interview with National Public Radio, Bohannon admitted the intent behind this elaborate hoax, saying: “My goal was to show that scientists who do a bad job and get their work published can end up making headlines because it’s us — journalists like you and me — who are failing. [Because the media often fail to do due diligence], the world is awash with junk science.”

Undoubtedly, a journalist reporting on scientific news should be able to deconstruct a scientific article from any source and critically engage with it. However, to put the onus on media journalists would be misguided. Scientists must hold themselves accountable, performing accurate work and ensuring that their findings are relayed not only to fellow colleagues, but to the lay audience in a comprehensive manner. As it stands, with communication between scientists and the public continually strained, Bohannon’s exercise only perpetuates the divide between these two sides. Revealing his fraudulent ways, he – intentionally or not – establishes himself as the superior, and those who “regurgitated” his press release to the masses are portrayed as lesser for it. A more conducive approach on Bohannon’s part may have been a critical, accurate depiction of up-to-date nutritional science as a way to demystify a niche oversaturated with fake news. Instead, the work spearheaded by Bohannon leaves even the sweetest tooth unsatisfied.

1. International Press Release: Slim by Chocolate. (2015).
2. Eating Chocolate Can Help You Lose Weight – Really! – Ready Set Health. Available at:
3. Bohannon, J. I Fooled Millions Into Thinking Chocolate Helps Weight Loss. Here’s How. io9 Available at:
4. Bohannon, J. Who’s Afraid of Peer Review? Science. 342, 60 – 65 (2013).
5. Bohannon, J., Koch, D., Homm, P. & Driehaus, A. Chocolate with high Cocoa content as a weight-loss accelerator. Int Arch Med. 8, 1 – 8 (2015).
6. Trickster Journalist Explains Why He Duped The Media On Chocolate Study. Available at:
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Ellinore Doroshenko

Ellie is a Master’s student in the Department of Immunology at the University of Toronto, where she investigates a mouse model of Multiple Sclerosis. Apart from lab work, she dabbles in yoga, likes to travel and is an avid downhill skier.
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