Real Food (2006)
Nina Planck
343 pages, $23.95
Everyone has heard of the scientific method, but few people seem to understand what it is. As a former science teacher, I feel a sense of responsibility about this, so here’s the one-minute version. The scientific method works like this:
1. Make an observation.
2. Form a hypothesis that fits the observation.
3. Design and perform an experiment to test the hypothesis.
4. Based on the results of the experiment, either toss out the hypothesis or say that the experiment supports the hypothesis. If many experiments performed by many different investigators support the hypothesis, you reach a scientific consensus–as close to “fact” as you can get with science.
But that’s no fun, is it? Doing experiments is expensive and messy. Here’s a more popular version of the scientific method.
1. Make an observation.
2. Form a hypothesis that fits the observation.
3. There is no step three.
This version is awesome. It saves a bundle of cash and you get to spend your time writing books and appearing on talk shows instead of pipetting. It doesn’t work at all, but hey.
It’s the streamlined scientific method on display throughout Nina Planck’s _Real Food_, an appealing but thoroughly frustrating polemic. It’s not a cookbook: it’s a renegade (sort of) scientific analysis of what we should and shouldn’t eat. There are chapters on meats, fats, dairy, vegetables, and so on.
_Real Food_ is appealing because Planck likes to eat the same kinds of things I do. She’s in favor of lard, cheese, eggs, organic produce, and other tasty things. Basically she likes all the things you get at the farmers market, which is perhaps not surprising, since she heads a farmers market organization.
Planck is admirably skeptical about some nutritional research. Much of this mainstream research, the kind that suggested that low-fat diets protect against heart disease, is based on observational studies. You recruit a group of people, examine their behavior, and correlate their behavior with the medical outcome you’re studying. At the same time, you attempt to control for confounding factors like sex, race, income, and so on.
This approach is a great start. It’s step one of the scientific method. If you notice an interesting correlation (maybe people who eat lots of yogurt get the flu less often), that takes you to step two. If you then form conclusions based on your hypothesis, you are in a state of scientific sin.
When mainstream researchers make this mistake, which they do all the time, Planck pounces on them. She then promulgates fringe research that, while based on interesting observations, is on even less sure footing than the mainstream research.
For example, on page 93, Planck claims that breast, testicular, and prostate cancers are have risen substantially since 1950 because of synthetic hormones in cattle. Well, that’s certainly an intriguing hypothesis. Let’s take a look at the research she cites. Oh, wait, there’s no citation.
If hormones are the enemy, omega-3 fatty acids are the white knight. They cure depression, schizophrenia, obesity, heart disease, and diabetes. Here Planck does give a citation–to a book by a psychiatrist called _The Omega-3 Connection_.
Look, I’m not saying that cow hormones are good for you and omega-3s aren’t. At least in the case of omega-3s there are actual intervention studies which have found that, for men, increased consumption of fatty fish lowered death rates–although it’s impossible to say from that whether the improvement was due to omega-3s or something else.
This is a book about food, and Planck seems to think this makes her free to ignore any health effects not related to food. She spends a lot of time talking about the remarkable health of hunter-gatherer societies compared to industrial societies. Let’s accept that assertion (although Planck doesn’t offer a whole lot of evidence). Wouldn’t you expect traditional and industrial societies to differ in ways other than food? What if all of the effects she’s talking about are related to stress rather than diet? I certainly don’t know if this is the case. Neither does Planck.
Let’s go back to the issue of dietary fat for a minute.
A causal relationship between consumption of dietary fat and cardiovascular disease has been suspected since the 1950s. There have been hundreds of observational studies on the topic, but the first large intervention study was completed in 2006. The study cost $415 million, which is why studies like this don’t happen often. I know you heard about this in this news, but the finding was entirely negative: that is, there was no evidence that reducing dietary fat intake reduced the risk of cardiovascular disease.
The study was criticized on several grounds. Maybe the researchers didn’t look at saturated fat intake. (They did.) The results only apply to older women. (True, but based on what we know about lipid metabolism, they’ll probably generalize to older men.) Finally:
> But the scientists declined to call the $415 million venture a failure, pointing to signs of less breast cancer in women who cut out the most fat, and in less heart disease in women who ate low amounts of the worst kinds of fats.
That’s called cherry-picking, rummaging around in your data for *something* statistically significant. Bad idea–it means you’re looking for an answer that the study wasn’t designed to provide.
What does this have to do with _Real Food_? Well, the link between fat and heart disease is one of the best-established tenets of our nutritional orthodoxy. There is a ton of evidence suggesting a relationship between saturated fat, cholesterol, CHD, and stroke. It was smart to make dietary recommendations based on this very suggestive data.
It cost $415 million to determine that these recommendations were probably wrong. Maybe not. Maybe the subjects were too old to make a difference. Maybe the hypothesis was correct but the results weren’t statistically significant. You can’t make an all-encompassing conclusion on the basis of one study.
But this is the *best evidence we have*. It’s much better than the evidence in favor of fish oil or blueberries. It’s much better than the evidence against white sugar and trans fats (two more of Planck’s demons).
I wanted to like this _Real Food_ as much as I like lard, eggs, raw-milk cheese, and fresh marionberries. There is scant evidence that any of these things are bad for you, and if you enjoy them, you should eat them. If only Planck had stuck to that message.
Right on! I’m an epidemiology graduate student and an enthusiastic farmers market shopper. I heard about 5 minutes of her talk at the Columbia City Farmers Market, shook my head in disgust at her “scientific” conclusions, and did my shopping. I greatly appreciate her work in starting farmers markets (and her food samples were great), but this missuse of scientific studies drives me batty, and I find it prevalent in both food and natural health circles. While pointed, I think your comments on the book are fair.
Wow, thnak you for your 1-minute version of the scientific method vs the pseudo-scientific method! I will use it every time I am trying to explain why “the latest study” reported in the news doesn’t conslusively prove anything. I am a physician and I cringe every time I hear that stuff, and always have a hard time explaining to friends who “don’t believe in” standard medicine but are ready to buy into any number of schemes if people tell them they are “proven” and organic, or natural, or homeopathic etc etc. On the other hand, you also concisely point out how little solid evidence there is behind most standard medical practice and recommendations. Really, this post sums up the essence of what everyone should learn in school, yet, when you see what’s happening in places like Kansas (or the White House) you know our education system fails most Americans.
Thanks for the comments, folks. Although I was sort of hoping for angry comments from health food nuts or something.
Ken, I’m sure there is much in modern medicine that won’t stand up to scrutiny over the long term, and doctors cling to their superstitions as much as anyone else. (Hormone replacement therapy is the obvious big recent debunking.)
But one point I was trying to make is that it’s not surprising that we know so little about diet and health, because it’s *extremely* hard to do that kind of experiment. And while the scientific method is the only way we’ve come up with to separate truths about the natural world from fiction, it’s not intuitive. The normal way for people to figure out what’s true is to to deduce from observations. It’s been successful enough that it’s our natural form of problem solving.
Er, where was I going with this?
I had been hoping to attend Ms. Planck’s talk at the Columbia City Market, but couldn’t get away from work early enough. Now I’m glad that I didn’t. Thanks for removing one small regret from my life.
In my experience, step 3 of the pseudo-scientific method is to selectively seek out evidence that supports one’s hypothesis, actually more damaging than simply skipping the step…
If that’s what you’re looking for, Vince, then you’re going to love this book!
Re: medicine…exactly my point, mamster, medical practice suffers from fuzziness about what is scientific and what is tradition…the key is to be clear. Medicine has been making all kinds of whopping mistakes by basing practices on incomplete seemingly scientific observations (hormone replacement therapy is a great example).
The same should go for deciding what is healthy to eat…we can try to learn from science but we’re probably not going to get very far and we might end up with whopping mistakes instead (margarine, anyone?). Since this whole industrial civilization experiment is barely a blip in the history of our species, it seems to make a lot of sense to stick to the foods that allowed humanity to survive to this point (hint: there wasn’t any high-fructose corp syrup involved…)
Great points on the pseudo-science of Nina Planck, and without a doubt we have many comforts, medical & technological improvements for which we must thank the scientific method. However, I would like to ask your thoughts on Common Sense & Holistic Approaches.
My wife is an M.S. in Nutrition and an R.D… and I have read more studies in the Jouranal of American Dietary Association than I can number – it is quite evident that the scientific establishments gets caught up in these linear experiements that tend to just explain one tiny piece of a huge puzzle, and often ignore the interrelationships between the pieces.
I have full confidence that someday, many centuries from now, the scientists will have a decent understanding of the relationship between food & health, but giving how many times they have been wrong aboout things like Vioxx & even Tylenol and countless other topics, it would be foolish to make decision solely based on what the scientific community has established.
To me, common sense says that since Homo Sapiens have existed for about 130,000 years… and in that time we have spent more than 92% of our existence as hunter gatherers… that evolution has created our bodies to flourish as hunter gatherers.
So just taking a common sense approach to risk management would say that we are best off eating like hunter gatherers as much as adjusting for our post-industrial lifestyles.
So yes it may be true that sugars & refined carbs aren’t necessarily poision for us… but pragmatically we should minimize their consumption.
Thank you in advance for your response.
Eat_Nopal, thanks for the comment. I guess my answer is that I agree a little bit.
Taking your argument to its logical conclusion leads to raw-foodism. But cooking was a tremendous advance in human nutrition, even though we’ve only been cooking for a small fraction of our existence.
This doesn’t mean that I think the Twinkie is a similar advance. But the belief that “what is natural is good” so commonly leads to trouble that there’s a name for it: the naturalistic fallacy.
To me, the common-sense approach is to eat a wide variety of foods and figure that you will get some of whatever is beneficial about them but avoid large doses of whatever is harmful.