May 01 2009
Who Can You Trust For Diet Advice?
3D Brain MRI
Last time I gave you a list of 10 people you can’t trust for diet advice, but many of you were left wondering who can you trust? As I alluded to before, it is extremely difficult to give a generic answer to this question because, frankly, there is no single group of people I can point to and say, “These people always do it right.” This is never true.
Where To Start
In the comments on Wednesday, reader Steve Parker M.D. (blogger and author of The Advanced Mediterranean Diet – visit his new Diabetic Mediterranean Diet Blog) said he mostly relies on primary scientific literature for his information. “Primary” literature is the original study where the actual scientific data is published and analyzed. This is very different from a newspaper article or press release (what a newspaper article is based on).
Without a doubt going straight to the source is the best way to get the facts regarding food, health and nutrition, and this is exactly what I do.
The Catch
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It would be wonderful if we could all read the science directly and decide for ourselves how to eat for health and weight loss. But unfortunately, most people do not have access to these studies unless you are on a university campus or pay the exorbitant subscription fees (hundreds of dollars) for each individual scientific journal (there are thousands).
Moreover, unless you have extensive training in biological sciences (more than a bachelors degree), these papers will make no sense to you anyway. Some people try to get around this by reading only the abstracts, but reading an abstract to comprehend a scientific paper is like trying to understand a Seinfeld episode by reading the TV Guide (only more irresponsible).
This is the root of the problem.
Scientific experimentation and analysis is incredibly complex and requires decades of training. Therefore the general public needs the data translated into plain English and explained in simplified concepts. It is tempting to believe that anyone with the appropriate education and a knack for writing can provide this service, however the nuances of data interpretation make this very tricky business. It is frighteningly easy to spin ideas and make claims the data does not really support. This is even scarier when you think of health and how many lives are at stake.
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The difficulties that arise from this issue are far reaching. At the most extreme, we have seen that research funded by industry is biased toward a favorable result for the company conducting the research.
Another potentially dangerous scenario is the misinterpretation of data by press rooms and journalists, who then translate these false ideas to a wide audience. Finally there are well-meaning people who do their best to alert the public to important health concerns, but simply misinterpret the science for one reason or another.
Who Is Qualified?
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Scientists Although I myself may be biased, I am inclined to trust the opinions of well-respected (highly published) scientists in the field of food and nutrition. Luckily, several of these people have written wonderful books clearly explaining the basics of food and health. Although I am probably the only person under 50 to have ever read these books, they are wonderful resources that I recommend whole-heartedly.
Here are my favorites:
Eat, Drink and Be Healthy by Dr. Walter Willett
Mindless Eating by Brian Wansink
What To Eat by Marion Nestle
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Smart journalists Despite my tirade above, scientists are not the only ones with good diet advice. Some journalists have the intelligence and tenacity to uncover all the necessary information and convey it to their readers. To know if you have found this kind of journalist you must read their work and make critical judgments about the logic and conclusions drawn from the data provided.
I have read more bad than good books by journalists, so please be skeptical of what you find. Note: extended book reviews are on the future agenda at Summer Tomato (for short summaries please read the captions under the books in the Summer Tomato Shop).[amazon-product align="right" bordercolor="ffffff"]0143114964[/amazon-product]
So far the most thorough analyses I have read from any journalist are the works of Michael Pollan. I also think the work of Gary Taubes is essential reading.
These are the best books on food and health ever written:
The Omnivore’s Dilemma by Michael Pollan
In Defense of Food by Michael Pollan
Good Calories, Bad Calories by Gary Taubes
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Trained nutritionists and dietitians I have also been impressed by many of the nutritionists I have encountered (especially Dinneen at Eat Without Guilt – find her on Twitter @EatWithoutGuilt). Nutritionists and registered dietitians are specialized in nutrition, food and eating. These professionals are skilled at working closely with an individual to develop personal eating plans. Although they are not specifically trained to read and interpret scientific studies, their education ensures substantial familiarity with the literature on nutrition, putting them ahead of most medical doctors.
Conclusion
In general you should be more skeptical than accepting of diet advice–particularly if the recommendations sound very strange or unnatural to you. However there are many good resources if you are careful to choose them wisely.
I am always looking for more book recommendations. See what I have read in the Shop and leave your additions in the comments.
Thanks to everyone who has participated in this lively conversation!
If you enjoyed this post, you might want to subscribe to Summer Tomato and follow me on Twitter!
Tags: advice, dietician, Gary Taubes, journalism, Marion Nestle, Michael Pollan, nutritionist, recommendations, scientist, Walter Willett
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Great post, thanks Darya! I went to that link about the study of industry bias, and you’re right it was kind of jibberish to me. You have great points about non-biased parties interpreting those studies. How do you judge if it is a good study though?
I’m afraid that’s the hard part, Karin. A few things I consider are the validity of the experimental design, the quality of the controls, the rigor of the statistical analysis and how carefully conclusions are made.
This is why training and education are so important.
Nutritionist or dietitian
In WI, and in some other states I believe, anyone can call themselves a nutritionist. Legally, there are no education requirements here despite what the Bureau of Labor Statistics has on their website. So people without any advanced training can call themselves nutritionists. Or people with degrees from diploma mills. Buyer beware.
We also have registered dietitians who call themselves nutritionists. In part because the public seems to prefer this term to the dietitian term.
To legally call yourself a dietitian, one must have graduated from an approved bachelors program, completed 900 internship hours, pass the registration exam, and maintain continuing education.
Wow, I didn’t realize that. Thanks for the tip! That must be really frustrating for those of you who have put the work in.
Another book I’ve found to be essential for me is The Don’t Go Hungry Diet by Dr Amanda Sainsbury-Salis PhD. A great example of someone making headway with clinical trials AND translating all that data for the general population.
I have never heard of that book. Thanks for the suggestion!
Thanks for mentioning my book and blogs, Darya.
Here’s yet another problem with the scientific literature that you know about but most people don’t: publication bias. Science journals prefer to publish “positive” studies, so there’s bias against negative studies.
Example: Suppose researchers discover that bowling regularly is associated with a tripling of the risk of colon cancer. That’s news! It’s surprising. That’s a positive study. If the research appeared to be well-designed and conducted by reputable scientists, it would tend to get published. On the other hand, eight other studies find NO association between bowling and colon cancer. They are negative studies. That’s not surprising, and it’s boring. They are not nearly as likely to get published. So you’d never hear about them.
Let’s assume there is no association between bowling and colon cancer (probably there isn’t). I’m sure if you ran enough epidemioligic studies – say, 100 – you would find one or two that suggested and association, but this would be purely by chance. Those one or two “positive” studies are much more likely to see the light of day in a publication.
-Steve
Excellent point as usual, Steve.
You may want to add The China Study by Dr. T. Colin Campbell, to your list.
Funny you should mention the China Study, I was planning to write a review of it this week
This was a great set of articles. I use my nurse practitioner for advice, as she seems to be really up on nutrition, as well as supplements. She seems to know way more than my primary care doctor. Also, what are your thoughts on Dr. Andrew Weill? He’s local to Tucson, runs alternative medicine program here, and I’ve read a good many of his books. He seems to fit your criteria – what do you think?
Thanks for asking aboug Dr. Weill, Linda. I have heard a lot about him, some good some bad. I have been meaning to read his biggest book, but still haven’t gotten around to it. I will certainly keep you posted when I do!
Couldn’t agree with you more, Darya! I try to understand the studies, I’ve read all those books, am under 50, and am always hungry for more. But I was a lawyer for years, so I can read complicated stuff, and I’m also personally interested in those things. I think for the average person, however, it’s complete information overload/jibberish, and that coupled with the fact that their caregivers are usually clueless, leaves them acting on hearsay from friends, family & colleagues and relying on front-of-package claims from food manufacturers.
Great post, as usual. However, I don’t agree with your comment that you need more than a bachelor’s degree to understand scientific studies. Although this may be true with a lot of BSc degrees, dietetics graduates (as Linda Simon eluded to) are highly trained to read and interpret these studies within our 5 years of training, because it is so imperative to our work.
I can’t speak for all University dietetics programs, but I know this is how it is for most in Canada.
Keep up the great work!!
Agreed! 5 yrs of training definitely counts
I recently joined your site and find it mostly interesting. This topic, “who to trust” on dietary issues is especially important. That Michael Polland recommends that you don’t eat anything that your grandmother wouldn’t recognize as food should be a mitigating point about not trusting your own mother’s advice. After all, your mother supposedly learned everything she knew about food from your grandmother. The best advice I have is to be your own advocate and take responsibility for your diet. Read everything you can concerning your food and nutrition, moderate your intake, and enjoy life.
I agree with you that MD’s shouldn’t be giving nutrition advice to the nation as a whole or writing diet books. I also agree in treating USDA guidelines with skepticism. But I don’t know that individual scientists should be the gold standard either. I think the idea of a “panel of scientists” is better. There is always some objectivity in data interpretation and I think the any diet advice given to the public should be a productive of a collective of the best minds. The term “peer-reviewed” should be expanded here. And intelligent journalists (like Pollan) should certainly be included, of course.
You make a very valid point, and I’m glad to hear someone saying that we cannot trust our government or any government agencies for diet advice. However, I’m not entirely sure all scientists are the best qualified, either. I base this on the fact that, as Michael Pollan agrees, what we eat shouldn’t have to be complicated.
You are taking the very rare perspective of combining scientific evidence with accessible action steps. Your advice to eat your vegetables, skip processed food, learn to cook, etc., is very sound, straightforward, and simple.
My interest lies in the fact that if you told ten people this is what they should do to lose weight, prevent disease, and live longer, maybe one of them would actually do it. Figuring out what prevents people from following such simple, overarching principles is the key to getting people off processed foods and back in the kitchen.