by Marion Nestle

Currently browsing posts about: Diets

Jun 19 2018

What’s up with the retracted Mediterranean diet study?

In a most unusual action, the New England Journal of Medicine has retracted a 2013 study of Mediterranean diets and published a new version of it at the same time.

The studies asked participants to consume one of three diets: (1) a Mediterranean diet supplemented with extra-virgin olive oil, (2) a Mediterranean diet supplemented with mixed nuts, and (3) a control diet with advice to reduce dietary fat.

The authors describe Mediterranean diets as containing a

high intake of olive oil, fruit, nuts, vegetables, and cereals; a moderate intake of fish and poultry; a low intake of dairy products, red meat, processed meats, and sweets; and wine in moderation, consumed with meals.

The conclusion of the original, widely publicized, but now retracted study:

In this study involving persons at high cardiovascular risk, the incidence of major cardiovascular events was lower among those assigned to a Mediterranean diet supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet.

The conclusion of the newly analyzed version:

In this study involving persons at high cardiovascular risk, the incidence of major cardiovascular events was lower among those assigned to a Mediterranean diet supplemented with extra-virgin olive oil or nuts than among those assigned to a reduced-fat diet.

Looks the same, no?

The most thorough analysis of the study that I have seen comes from Hilda Bastian at PLoS Blogs.

Even for the full group, there was no statistically significant difference on myocardial infarction or CVD mortality – just for stroke. And in the supplementary information, there wasn’t a difference in the Kaplan Meier analysis for stroke either.

What are we to make of all this?

Diet trials are notoriously difficult to conduct and interpret and the Mediterranean diet—largely vegetarian with olive oil as the principal fat—was associated with great health and longevity based on studies of people who lived on the island of Crete immediately after the Second World War; they did not have much food to eat and were highly physically active.

And then there’s the matter of who paid for the study.  The retracted study and its revision were funded independently.  But a study published on June 13 concludes:

Adults who are overweight or moderately obese may improve multiple cardiometabolic disease risk factors by adopting a Mediterranean-style eating pattern with or without reductions in red meat intake when red meats are lean and unprocessed.

The funder?  The Beef Checkoff and the National Pork Board.

Overall, the 2015-2020 Dietary Guidelines for Americans recommends Mediterranean dietary patterns for their health benefits, defines what goes into them in Table 1.2 (p. 35), and provides more details in Appendix 4 (starting on p. 83).

Mediterranean diets are delicious.  While the scientists are arguing about exactly how healthy they might be, enjoy!

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Feb 8 2018

Annals of marketing: Meal replacements

A reader in South Africa, Effie Schultz, sends an item from NutraIngredients-USA about a new meal replacement product, Bear Squeeze, “packed with MCT [medium-chain triglyceride] oil, kale, pumpkin seed protein and probiotics.”  It is aimed at people on ketogenic (very low carbohydrate) diets.

The president of the company that makes this product, Max Baumann, says that he wants Bear Squeeze to be known as a “higher-end, cleaner Soylent.”

NutraIngredients says:

If there’s any indicator that a large group of consumers are stoked about a meal replacement powder formulated to meet the requirements of a ketogenic diet, let that be California-based Bear Squeeze’s performance on fundraising platform Indiegogo,​ ​where it raised 421% of its $25,000 goal, a good month before its fundraising deadline.

The brand also snagged the top prize​ at the new beverage showdown competition at BevNET Live last month, showing that Baumann has gotten the industry excited about his brand as well.

Why this product?  There is money—lots of it—to be made, apparently.

The impetus to start Bear Squeeze,…was seeing the success of meal replacement brands like Soylent, which recently moved from exclusively digital to brick-and-mortar. Soylent CEO Bryan Crowley said last month that sales performance in the offline channel “blew away expectations.”

I have to confess not getting this.  With plenty of healthy, delicious food around, and at a cost buyers of products like these can well afford, why would anyone want to substitute something that tastes pretty awful (I’ve tasted Soylent and doubt this can be much better) for fabulous food?  People who consume these products must not be foodies, alas.

Medium-chain triglycerides are easy-to-digest fats created and formulated for hospitalized patients with serious digestive difficulties.

I vote for food, glorious food, anytime.

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Jan 12 2018

Weekend reading: Diet and the Disease of Civilization

Adrienne Rose Bitar.  Diet and the Disease of Civilization.  Rutgers University Press, 2017.

Image result for Diet and the Disease of Civilization

I did a blurb for this one:

Bitar’s fascinating thesis is that diet books are ways to understand contemporary social and political movements.  Whether or not you agree with her provocative arguments, they are well worth reading.

I also took some extra notes because the publisher wanted a particularly short blurb.  As you might suspect from my brief comment, I have some quibbles with some of Bitar’s arguments, but the book is interesting, well written, and worth a look.

Bitar deals with four categories of diet books: Paleolithic, faith-based, South Seas paradise, and detox (this last category strangely includes Michael Pollan’s and my work).

Here’s a sample from the chapter I thought strongest, the one on Paleolithic diets.  It refers to classic images of man arising from apes, and then degenerating into obesity.

These images suggest what is much more explicit in the text—that the diet is a story about humanity, about evolution, about civilization and dis-mankind.  The body of the individual dieter is situated in a long, deep history of mankind.  The dieter is biologically indebted to the Paleolithic Era and, in turn, the coming generations will be indebted to him.  Everyday body practices of the individual—eating, sleeping, walking—are elevated to symbols of mankind’s ascent or descent, failures or triumph, in the grand narrative of progress (p. 41).

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Sep 29 2017

Weekend reading: Healthy and Sustainable Diets for Europe

I’m in Europe this week so especially interested in its public health efforts. This report is an example.

Healthy and Sustainable Diets for European Countries. Report of a Working Group. EUPHA (European Public Health Association), 2017.

The purpose of this report is to encourage public health professionals to promote policies that will enable individuals to make healthier food choices.  It’s a long report, but summarizes its goals in one quick table:

Aug 30 2017

Another ongoing saga: the legacy of Ancel Keys

I cannot understand the revisionist attack on the work of Ancel Keys, who died at the age of 100 in 2004.  Most scientists are lucky to have made important contributions in one area.  Keys produced outstanding work in several:

  • High altitude physiology
  • The physiology of starvation (for this alone, he should be honored)
  • Mediterranean diet benefits
  • Heart disease epidemiology

The fuss, of course, is over this last one, particularly his role in the Seven Countries Study.  The arguments falls right into today’s absurd debate about sugar vs. fat as a cause of disease (absurd, because we don’t eat sugar or fat; we eat foods and diets that provide energy measured as calories).

What started off this most recent fuss is Ian Leslie’s The Sugar Conspiracy, which begins with the question “How did the world’s top nutrition scientists get it so wrong for so long?”  This alone is a red flag.  “Everything you thought you knew about nutrition is wrong” is a sure signal for caution; that’s not how science works.

The attack on Keys’ work induced the True Health Initiative to develop a ​White Paper in defense (here’s its press release).  Its authors: Katherine Pett (who had written a blog post in defense), Joel Kahn (who also wrote a blog post) Walter Willet (long a champion of Mediterranean diets), and David Katz (who wrote about it in his own blog post).

In response, Michael Joyner pointed out that R.A. Stallones (a professor of mine at the School of Public Health at Berkeley) had made the same arguments years ago.

Another defense of Keys’ work comes from Kevin Klatt, a nutrition biochemistry PhD student at Cornell.

Sarah Tracy, a science historian at the University of Oklahoma, has been working on a biography of Ancel Keys for years.  I can’t wait for it to come out.  We need to have Keys’ life and work put in reasonable perspective.

While waiting for the fat v. sugar debate to resolve (I’m predicting it won’t), eat a healthy diet, enjoy what you eat, and be skeptical when writers write about nutrients, not food.

Jul 17 2017

Food-Navigator-USA Special Edition: Paleo Diets

Here’s another one of this site’s roundup of articles on specific topics, written from the perspective of food companies.  Paleo sells.

Special Edition: Paleo: Fad, Trend, or Movement?

Definitions vary, but most advocates of the Paleo diet think the dietary rot set in once humans stopped hunting and gathering and started to grow crops and raise animals for food. So grains, legumes, and dairy are typically off limits (although some Paleo fans say grass-fed dairy is OK). While critics say any diet that eliminates major food groups should be treated with caution, the number of products featuring Paleo claims and certifications is growing rapidly, and many retailers and manufacturers are now looking at how to tap into the trend, which some market researchers see as the next evolution of low carb, and gluten-free.

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Sep 7 2016

The well deserved fuss over the UK’s childhood obesity plan

The much delayed UK government’s plan for dealing with childhood obesity has finally been released to virtually universal dismay over the missed opportunity.

The strategy is now a Plan, and says it is “the start of a conversation.” It reconfirms the government’s intentions to implement a soft drink tax, subject to consultation, but does not include a range of measures recommended by its own Public Health England and by last year’s House of Commons Health Committee, such as reduce food marketing and controls on retail promotions. It relies on voluntary sugar reduction by the food industry and encouraging parents to help increase children’s physical activity to meet the recommended 1 hour per day.

It’s fun to read the criticisms: nobody minces words.

An editorial in The Lancet

The UK Government’s long-anticipated response to the childhood obesity crisis disappointed everyone. From doctors, health charities, and celebrities to the very industry it seeks to propitiate, the Childhood Obesity Plan, published with as little noise as possible in the summer recess, has met with resounding criticism. As a Comment in today’s Lancet highlights, the strategy has been delayed for a year, and in that time it has been watered down to a vague Plan with no teeth.  Reading the report from start to finish gives the impression that its authors haven’t.

The Lancet editorial continues

The absence of curbs on industry practices that contribute to childhood obesity—promotions of unhealthy food in supermarkets and restaurants; advertising of junk food through family TV programmes and social media—seems like a gift to industry.

The Lancet is especially miffed because it ran a series on obesity last year that made it clear what kinds of policies needed to be enacted.

Also in The Lancet, World Obesity’s Tim Lobstein and Klim McPherson say

What we read in the government’s Plan is nothing particularly new, nothing bold, and very little that can actually be measured to assess the Plan’s success. It is a document that is not only a disappointment to public health professionals, but also evidence of a government walking away from its moral duty to protect the health of children, and its fiscal duty to protect the NHS from the consequent costs.

The Association for the Study of Obesity (ASO) issued a statement:

the plan is a lost opportunity to provide leadership and commitment in tackling childhood obesity as part of a whole systems approach. It lacks bold actions that are needed to reverse the current high levels of child obesity such as: a ban on junk food advertising before the 9pm watershed; reduction in portion sizes; reformulation targets for industry that address high energy density foods; curbing the promotion of unhealthy foods in supermarket; investment to increase and extend evidence-based child weight management services. All of these would be robust, evidence-based actions and would start to tackle the root causes of obesity in this country.

Again in The Lancet, Yoni Freedhoff and Kevin Hall point out the need for more sensible weight loss studies:

Over the past several decades, dozens of randomised controlled trials have compared various diets for the treatment of obesity. Ideally, such studies should have provided strong evidence for clear clinical recommendations and also put a stop to society’s endless parade of fad diets. Unfortunately, the evidence base remains contested and the “diet wars” continue unabated…What is especially striking is the similarity of the long-term pattern of mean bodyweight change, irrespective of diet prescription.5 …Fewer resources should be invested in studying whether or not a low-carbohydrate diet is marginally better than a low-fat diet, or whether intermittent fasting provides marginally better short-term outcomes than a so-called Paleo diet.

Their study provides further evidence why we need stronger policies for preventing obesity.  It’s too bad the UK couldn’t do better.

And if you think things are any better in New Zealand

The food industry has hit out at claims in a leading journal that New Zealand’s childhood obesity plan was flawed and that the government valued corporate profit over public good. The Food and Grocery Council said that an editorial in the New Zealand Medical Journal, which claimed that the government’s strategy did not address excess sugar intake, was “flawed on many fronts.  Moreover, the FGC complained that its response to the article, solicited by Fairfax Media, was not run.

Addition, September 14

Aug 17 2016

Confused about diet? Oh, please.

I breathed a long sigh when I read Gina Kolata’s We’re So Confused: The Problems With Food and Exercise Studies in the New York Times on August 11.

Nearly everything you have been told about the food you eat and the exercise you do and their effects on your health should be met with a raised eyebrow… The problem is one of signal to noise. You can’t discern the signal — a lower risk of dementia, or a longer life, or less obesity, or less cancer — because the noise, the enormous uncertainty in the measurement of such things as how much you exercise or what exactly you eat, is overwhelming. The signal is often weak, meaning if there is an effect of lifestyle it is minuscule, nothing like the link between smoking and lung cancer, for example.

This is a pessimist’s view.  I, however, am an optimist.

Nutrition advice could not be easier to understand.  Eat plenty of vegetables and fruits; balance calories; don’t eat too much junk food.

David Katz must agree.  He asks: Diets, Doubts, and Doughnuts: Are We TRULY Clueless?

No, we are not, absolutely not, emphatically NOT clueless about the basic care and feeding of Homo sapiens…In the New York Times this past week, Gina Kolata made the case that almost all studies about diet, exercise, and health are suspect in one way or another, and that therefore we are confused about lifestyle practices for health, and justifiably so. The first point is valid; the second is utter nonsense…A global consensus of expert judgment concurs… Routine physical activity and a diet of mostly minimally processed vegetables, fruits, whole grains, beans, lentils, nuts, seeds and water when thirsty redounds consistently to the advantage of human health. It offers benefits to the planet as well.

Or, as Michael Pollan famously put it:

Eat food, not too much, mostly plants.

Articles like that one add to the confusion; they don’t help clear it up.

 

 

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