Lab coat doctor with blackboardAny good fad diet marketing will have a few personal testimonials about how eating this or not eating that helped someone lose weight. Unfortunately, this runs afoul of the principle that the plural of anecdote is not data. This week, in response to a tale that an “alkaline diet” cured a retired actress of cancer, British oncologist (cancer specialist) Karol Sikora penned an open letter to the Daily Mail newspaper objecting to the claim that any diet can do that. He writes:

I have looked at quite a few faddy diets which claim to help cancer patients over the 40 years I have been practising as an oncologist.[...] I can honestly say I have never found one that does what it claims to do. Mostly, these diets help people who want to feel they are ‘doing something’ to help themselves when they have a life-threatening disease.

Dr. Sikora’s ought to also write an open letter to the animal rights radicals at the so-called Physicians Committee for Responsible Medicine (PCRM)–only 10 percent of whose members are in fact physicians. PCRM runs a campaign called the “Cancer Project,” which purports to show that veganism prevents cancer—that is, when the group is not threatening to file baseless lawsuits against restaurants that sell chicken.

No wonder then that McGill University chemistry professor Joe Schwarcz strongly criticized PCRM for “cherry-picking data” and “masquerad[ing] as a just scientific body” in creating its scaremongering campaigns. The Daily Show saw through the smokescreenkeeping up the show’s habit of exposing animal rights radicals and food prohibitionists with good humor.

Sikora’s experiences are backed up by the evidence. A study that we mentioned in passing early last month found that diet and cancer risk is poorly understood. A researcher from Stanford University found that “a large portion of [claims that certain foods affect cancer risks] seem to be wrong indeed.” That might not convince PCRM’s lab-rat liberation league, but it might just ease some stress for the 99 percent of us who aren’t animal rights radicals.