Scientists tallied up all the advice on Dr. Oz’s show. Half of it was baseless or wrong.

For years, I’ve been looking at some of the dubious and harmful health claims TV doctors make on their talk shows. In carefully examining Dr. Oz, unpicking the evidence behind the products he peddles, I came to the conclusion that, on balance, the bulk of what he has to say is misleading at best, and total nonsense at worst.

He is, after all, in the business of entertainment. Real, evidence-based medicine isn’t often entertaining, especially on the subjects — weight loss, diets — he tends to cover.

Now, science has confirmed my suspicions.

Researchers writing in the British Medical Journal last December examined the health claims showcased on 40 randomly selected episodes of the two most popular internationally syndicated health talk shows, The Dr Oz Show and The Doctors.

They identified 479 recommendations from The Dr Oz Show and 445 recommendations from The Doctors, finding that on average, each episode contained about a dozen bits of health wisdom.

By randomly selecting the episodes, instead of cherry picking the worst offenders, their findings give us a true picture of the quality of the health claims that are being made.

And what they found was disappointing but not exactly surprising: about half of the health recommendations had either no evidence behind them or they actually contradicted what the best-available science tells us. That means about half of what these TV doctors say to their millions of satellite patients is woo, and potentially harmful and wasteful woo at that.

You can see the findings neatly visualized here in these pie charts:

On The Dr Oz Show, the bulk of the health recommendations had to do with dietary advice (such as “Carb load your plate at breakfast”), while the Doctors mainly told their viewers to consult a healthcare provider (“Go to your primary care doctor or talk to their nurse before going to the ER to help relieve the load in the ER”).

The benefits of many of their health claims were played up, but harms were barely mentioned, and neither were potential conflicts of interest.

“Anyone who followed the advice provided would be doing so on the basis of a trust in the host or guest rather than through a balanced explanation of benefits, harms, and costs,” the study authors write. “The near absence of potential conflict of interest reporting further challenges viewers’ ability to balance the information provided.”

Given the low quality of the advice from TV doctors, the study authors suggest, “Consumers should be skeptical about any recommendations provided on television medical talk shows, as details are limited and only a third to one half of recommendations are based on believable or somewhat believable evidence.”

I’m not sure we needed researchers to tell us that, but it’s nice to be able to quantify the quackery on TV.
Read more: Why Dr. Oz can say anything and keep his medical license, Dr. Oz’s three biggest weight loss lies, debunked, and Meet the medical student who wants to bring down Dr. Oz.