by Marion Nestle

Archives

Jan 9 2013

Let’s Ask Marion: Can It Really Be Healthier To Be Overweight?

Every now and then, Kerry Trueman challenges me with a difficult question about some current topic.  Our most recent exchange, published yesterday in the Huffington Post, is about the so-called “obesity paradox” (defined below).

Trueman: There’s a brouhaha in the blogosphere over Paul Campos’ NY Times op-ed in which he claims that our current definition of what constitutes a ‘healthy weight’ is dead wrong. Campos cites a new analysis from The Journal of the American Medical Association claiming that overweight or obese individuals have a lower mortality rate than people whose weight is ‘normal.’

He speculates that our obsession with obesity is a misguided and manufactured controversy foisted on us by the multibillion dollar weight loss industry and Big Pharma. Marion, you’ve been called a lot of things over the years, but have you ever been accused of being in cahoots with Jenny Craig and Eli Lilly?

Nestle. I love it when people invoke conspiracy theories to deny that obesity raises disease risks.

Paul Campos is a lawyer. He views matters of diet and health from a legal perspective. From that viewpoint, if a statistical analysis shows little effect of obesity on mortality except among very obese people, then nobody need be concerned about weight gain except at the extreme.

If only the science of diet and health were that simple. Scientists, alas, must struggle with a number of vexing questions about such studies:

  • Does a finding of statistical significance necessarily imply clinical or biological significance?
  • Do statistical findings based on populations necessarily count for individuals?
  • Do statistical associations provide guidelines for behavior?
  • Are the methods used in statistical studies adequate to draw conclusions about behavior?

We are talking here about a huge meta-analysis of 97 studies of obesity and mortality carried out by Katherine Flegal and her colleagues at the National Center for Health Statistics.

When I read papers by excellent statisticians published in prestigious, peer-reviewed journals, I start by taking the results at face value. Then I ask critical questions about what the results might mean.

I found the figures in the paper difficult to follow so I’ve summarized the results below:

RELATIONSHIP OF WEIGHT CATEGORY TO THE RISK OF MORTALITY.

WEIGHT CATEGORY BMI RANGE MORTALITY RISK (RELIABILITY)
Normal 18.5 – 25 1.00
Overweight 25 – 30 0.94 (95% CI, 0.91-0.96)
Obesity, Grade 1 30 – 35 0.95 (95% CI, 0.88-1.01)
Obesity, Grades 2 and 3 >35 1.29 (95% CI, 1.18-1.41)

My interpretation: Compared to people with BMI’s in the normal range, those with BMI’s considered overweight or somewhat obese display no increased risk of mortality. Indeed, those in the obesity grade 1 category may have a slightly reduced risk. The study only finds an increased risk of mortality—by 29%—when the BMI exceeds 35.

My first reaction? This is not news.

Since this is a study of previous studies, we’ve seen results like this before. Flegal herself published a similar analysis in JAMA in 2005. In that paper, she presented the results in a way that is easier to visualize:

RELATIONSHIP OF BMI TO MORTALITY AT VARIOUS AGES

2013-01-08-BMI1.png

2013-01-08-BMI2.png

These earlier results show what is called a “J-shaped” curve, meaning that the risk of mortality increases at BMI’s below as well as above the normal range.

The new study is consistent with these earlier—and equally controversial—results.

But the earlier results point to some of the difficulties in interpretation.

  • What’s going on at the lower end of these curves?
  • Are mortality results skewed by people who are ill and weigh less?
  • Is BMI an adequate indicator of health status?

At the moment, there is no way to answer these questions at a level of precision that might satisfy legal thinkers.

What we do know is that obesity above the normal range sometimes—never always—raises the risk for chronic diseases like type 2 diabetes, heart disease, and others. Risk is about probability. Risk never implies legal certainty.

It seems clear that for some people—perhaps many—having a chronic disease does not cause a decrease in lifespan. Since 1970, people throughout the world have gained slightly more than ten years of life expectancy overall, but are now spending many more years living with injury, illnesses, and disabilities—conditions caused by cigarette smoking, excessive alcohol consumption, and poor diet.

With respect to overweight, this is sometimes called the “obesity paradox,” understood as the survival benefits of modest overweight and obesity for people who already have a specific medical condition.  For them, many studies—not all—show that survival is modestly better at higher weights.

The Flegal study deals only with the statistical significance of the mortality survival component of the paradox. It does not deal with issues related to the effects of obesity on quality of life.

As a result, some of my colleagues have made harsh comments about the study, calling it “a pile of rubbish.”

I wouldn’t go that far. The study is what it is—a statistical meta-analysis. It’s up to scientists and clinicians to figure out whether statistics like these have meaning in the real world.

In the real world, it doesn’t take much overweight to induce type-2 diabetes in susceptible individuals, and many people—not all—with type-2 diabetes can completely eliminate symptoms by losing a few pounds.

Campos may be willing to let his weight go to where it will and take his chances that statistics are on his side. That’s his choice.

As for me, I’d prefer to avoid weight-related illnesses for as long as I can. I’m hedging my bets and continuing to watch my weight.

Jan 8 2013

A Man. A Plan. Panamá!

On vacation in Panamá, I found few visible signs of food politics.

I had asked to visit the mountain site where genetically modified salmon are being raised in the mountains (see previous post).  Not a chance.

This made me even more curious.  I conducted an informal survey of every educated Panamanian I met:

  • Are you aware that genetically modified salmon are being raised in your country?
  • Do you care?

The answers: No and No.

I found only two exceptions: (1) a government official impressed by what he told me were five levels of security to make sure the fish don’t escape, and (2) an associate of the soon-to-open biodiversity museum (designed by Frank Gehry) who hoped that the museum could be a forum for such issues.

Both confirmed that the newspapers said nothing about GM salmon and that few people knew about them.

A chef’s reaction: Panamanian salmon!  He couldn’t wait to get some.

But I did see this Christmas display along the Avenida Balboa.

The Coca-Cola banner also says Alcaldía de Panamá: trabajando para ti (Mayor of Panamá City: working for you).

Happy new year!  Happy to be back.

Dec 29 2012

FoodPolitics.Com is taking a vacation

FoodPolitics.com will return on January 7.

May the new year bring much joy and a healthier, more sustainable, and delightfully delicious food system for all.

 

Dec 28 2012

The FTC’s latest report on food marketing to kids: glass half full or empty?

Last Friday was a big day for releasing reports that federal agencies would rather keep quiet.  As I discussed in my previous post, the FDA released its long overdue environmental impact report on GM Salmon.

Today, let’s take a look at the FTC’s latest report on the state of food and beverage marketing aimed at children. This is a follow-up to the report the FTC issued in 2008.

The new report cites progress.  From 2006 to 2009, its press release says:

  • Total spending on food marketing to youth ages 2-17 dropped from $2.1 billion to $1.79 billion, mainly because of less spending on television advertising.
  • But spending on new media, such as online, mobile, and viral marketing, increased by 50 percent.
  • Cross-promotions that link marketed foods with popular children’s movies and TV characters increased from 80 children’s movies and TV shows to 120.
  • Cereals had 0.9 gram less sugar and 1.6 grams more whole grain.
  • Fast food was a  little lower in calories, sodium, sugar, and saturated fat.

The report concludes:

Despite the commendable progress, this report identifies areas where further efforts could be made by the food and beverage industry and the media industry to improve the nutritional quality of foods marketed to youth.

Whether you see this as good news or not such good news depends on whether you see the glass as half full or half empty.

If you are a half-full type, you will rejoice that food companies are voluntarily improving the nutritional quality of their products even if the improvements are small.

If you are a half-empty type (which, in this case, I am), you will be dismayed at the lack of real progress in reducing the marketing of junk foods to kids.

Companies must sell more and more products to grow their businesses.  They are under pressure to reduce such marketing and to improve the quality of the products they sell.  Neither change is likely to increase sales.   Hence: resistance to change.

As Andy Bellatti points out, small nutritional improvements are unlikely to have much of an effect on health: reducing the sugars by 0.9 grams can be interpreted as “better for you” but does not necessarily make a product a good choice.

And as Michele Simon’s interview with former marketer Bruce Bradley suggests, the data on which the FTC based its positive assessments may well have been gamed by the companies reporting it.

As I read this report, it provides plenty of evidence that stopping food and beverage marketing to kids is the issue that matters most to doing something to reverse childhood obesity.

The election is over.    Maybe Let’s Move! can revisit the marketing-to-kids issue.  Someone needs to do it.  And soon.

 

Dec 26 2012

The hazards of GM foods: patent protection and international relations

Writing in Slate, Fred Kaufman takes a fresh look at the controversies over genetically modified (GM) foods.  Forget the other issues, he says.   Pay attention to patents:

GM foods’ effect on health is uncertain, but their effect on farmers, scientists, and the marketplace is clear. Some GM foods may be healthy, others not; every genetic modification is different. But every GM food becomes dangerous—not to health, but to society—when it can be patented. Right now, the driving force behind the development of new genetic crop modifications is the fact that they possess the potential to be enormously profitable….

That brings me to the GM salmon, in particular AquAdvantage brand engineered to grow faster and bigger than wild salmon.

Last Friday (always a good time to release something controversial), the FDA let loose its draft environmental assessment on the GM salmon.  The draft finding of “no effect” is now open for comment.

I find the draft statement remarkable for two reasons.

  • It is dated May 4, 2012, suggesting that it was considered too political to release before the election.
  • It applies only to production of GM salmon outside the United States.

The FDA had already ruled that the salmon are safe to eat:

With respect to food safety, FDA has concluded that food from AquAdvantage Salmon is as safe as food from conventional Atlantic salmon, and that there is a reasonable certainty of no harm from consumption of food from triploid AquAdvantage Salmon. Further, FDA has concluded that no significant food safety hazards or risks have been identified with respect to the phenotype of the AquAdvantage Salmon.

With respect to environmental impact, the FDA says:

FDA preliminarily concludes that the development, production, and grow-out of AquAdvantage Salmon under the conditions proposed in the materials submitted by the sponsor in support of an NADA [New Animal Drug Application], and as described in this draft EA [Environmental Assessment], will not result in significant effects on the quality of the human environment in the United States.

AquAdvantage is not intended to be grown in the United States.  It is being raised on Prince Edward Island in Canada and in Panama and will be processed in Panama.

Under the proposed action, AquAdvantage Salmon would not be produced or grown in the United States, or in net pens or cages, and no live fish would be imported for processing.

…As the proposed action would only allow production and grow-out of AquAdvantage Salmon at facilities outside of the United States, the areas of the local surrounding environments that are most likely to be affected by the action lie largely within the sovereign authority of other countries (i.e., Canada and Panama).

Because NEPA [the National Environmental Policy Act] does not require an analysis of environmental effects in foreign sovereign countries, effects on the local environments of Canada and Panama have not been considered and evaluated in this draft EA except insofar as it was necessary to do so in order to determine whether there would be significant effects on the environment of the United States….

In addition, social, economic and cultural effects of the proposed action on the United States have not been analyzed and evaluated because the analysis in this draft EA preliminarily indicates that the proposed action will not significantly affect the physical environment of the United States.

If I am getting this right, the FDA is saying that since the salmon is being raised elsewhere, it’s OK to produce it.

This report is generally interpreted as opening the door to marketing of GM salmon within the United States, and soon.

Will it be labeled as such?  I suppose that too is up to Canada and Panama.

Revisit patent protection anyone?

Dec 22 2012

All you need is a rutabaga and a dream

I’m just back from attending the 15th annual International Rutabaga Curling Championship at the Farmers’ Market in  upstate Ithaca, New York.

This year’s championship event took place, as always, on the last day of the farmers’ market season.

Rutabagas, for the unitiated, are root vegetables of the Brassica family, most likely originating as a cross between a turnip and a cabbage.

Unlovely as they may be, rutabagas are just right for rolling down an icy lane (you can cook and eat them afterwards).

Before the festivities begin, the chorus does a quick rehearsal, this one filmed by a Japanese photographer for a reality show of unusual sporting events.  The program sent a crew to participate, making this a truly international event.

The event has its own original song, Joe Crookston’s The Rutabaga Curl.

But beyond the sport, the high point is always the sing-along rendition of the Rutabaga Chorus.   Its words are explained as the original lyrics for a tune later repurposed for Handel’s Messiah.

My favorite line: “Re-peat re-frain forever and eeeeever….”

Happy holidays!

Dec 21 2012

Ad Age’s thought for the weekend: McScrooge or McSavior?

For an average take of $5,500 (that’s all?), McDonald’s will be open on Christmas day.  So says an investigative report by Advertising Age, which managed to get a hold of some internal McDonald’s memos.

And no, they won’t get overtime pay.

 

Happy holidays, everyone.

Dec 20 2012

Beyoncé’s Pepsi deal: Implications for Let’s Move!

In response to my post a couple of days ago about Beyoncé’s Pepsi deal, a reader asks:

How do you think the White House should respond to this deal.? Beyoncé’s song is featured on White House website and a Let’s Move! t-shirt she designed is given to kids at official events.  Will kids make the connection?  Can all that dancing overcome the effects of eating too much?

Let me deal with these one at a time.  First, the problem this poses to Let’s Move!  People concerned about the role of sugary sodas in childhood obesity are appalled by Beyoncé’s deal with Pepsi, so much so that the Center for Science in the Public Interest has organized a campaign to call on her to reconsider.   Unless she does reconsider and withdraws from the deal, her continued involvement with Let’s Move! raises exactly the questions you ask.

Beyoncé has just put Let’s Move! in a painfully awkward conflict of interest.  On the one hand, Let’s Move! promotes healthy diet and activity patterns to reverse childhood obesity.  On the other, its celebrity spokesperson is now going to be pushing Pepsi.  Beyoncé’s image will now appear on Pepsi cans—I hope not wearing her Let’s Move! tee shirt.

What the Beyoncé deal points out is the hazard of partnerships and alliances between public health groups and food companies.

In April 2011, the Washington Post reported that “A White House spokesman said that the first lady and her team weren’t involved in the making of the clip but that Beyonce is “a great example of how people can get involved with ‘Let’s Move!’ and bring this message to more and more young people.”

But now this.  The White House has long maintained that food and beverage companies are not going away and that it is obliged to work with them.  Maybe, but on whose terms?  I see Beyoncé’s $50 million partnership with Pepsi as a slap in the face to Let’s Move!  It puts Let’s Move! in the position of promoting Pepsi or asking Beyoncé to withdraw from having anything to do with it.

As for how kids are going to figure this out:  All kids know is that Beyoncé is a gorgeous mega-star, one who is able to perform vigorous dance moves in astonishingly high heels, and that Pepsi helps her do so or at least doesn’t hurt.  Beyoncé is especially a role-model for African-American kids.  Pepsi targets its marketing to African-American kids.  This looks like a serious conflict of interest.

On the balance between diet and activity: How I wish that physical activity alone could reverse obesity.  Physical activity is terrific for health (I’m not sure about those stiletto heels) but it’s rarely enough to reverse obesity on its own.  To lose weight—and, these days, to maintain healthy weight—kids absolutely must eat less and eat better.

Beyoncé has done Michelle Obama no favor by getting involved with Pepsi.  This is a mess, and not one that can be gracefully fixed.