by Marion Nestle

Currently browsing posts about: Fats-and-oils

Sep 28 2015

Never a dull moment: the BMJ’s attack on the Dietary Guidelines Advisory Committee report

Really, the Dietary Guidelines Advisory Committee’s (DGAC) report shouldn’t be this controversial and shouldn’t be controversial at all (as I’ve said before).  But lots of people—the food industry, of course, but also some scientists and journalists—seem to have exceptionally intense opinions about the fat recommendations [Recall:  The DGAC report does not constitute the Dietary Guidelines; these are written by USDA and HHS and are not due out until the end of this year].

Now, we have the journalist Nina Teicholz, author of The Big Fat Surprise, repeating the themes of her book in the BMJ: The scientific report guiding the US dietary guidelines: is it scientific?.

The BMJ has also found that the committee’s report used weak scientific standards, reversing recent efforts by the government to strengthen the scientific review process. This backsliding seems to have made the report vulnerable to internal bias as well as outside agendas.

Teicholz’s interpretation of the science relating dietary fat to health has been thoroughly critiqued (see end of post).   The way I see it, these arguments are difficult to resolve outside the context of dietary patterns as a whole.

My hypothesis (note: hypothesis) is that for people who balance calorie intake with expenditure, the type of fat—or carbohydrate—matters much less than it does for people who overeat calories.  This hypothesis needs testing to confirm it.

What troubles me about Teicholz’s work is the certainty with which she presents her ideas.  She comes across as utterly convinced she is right, even in the face of substantial and substantive criticism of her statements and interpretations.

At least one error

Here, for example, is one statement in the BMJ article that I know from personal experience cannot be correct.

Much has been written about how industries try to influence nutrition policy, so it is surprising that unlike authors in most major medical journals, guideline committee members are not required to list their potential conflicts of interest.

I was a member of the 1995 DGAC and I was required to declare conflicts of interest.  So were members of the committees in 2000, 2005, and 2010, as shown in this excellent short video.

Later, discussing conflicts of interest among DGAC members, Teicholz says:

Still, it’s important to note that in a field where public research dollars are scarce, nearly all nutrition scientists accept funding from industry. [Nearly all?  I don’t, and I doubt this is correct].  Of far greater influence is likely to be bias in favor of an institutionalized hypothesis as well as a “white hat” bias to distort information for what is perceived as righteous ends.

The “white hat bias” comment refers to a paper by authors who themselves report food-industry funding:

Competing Interests. Drs. Allison and Cope have received grants, honoraria, donations, and consulting fees from numerous food, beverage, dietary supplement, pharmaceutical companies, litigators, and other commercial, government, and nonprofit entities with interests in obesity and nutrition including in interests in breastfeeding and NSBs. Dr. Cope has recently accepted a position with The Solae Company (St Louis, MO.).

Responses to the BMJ article

The DGAC wrote a rebuttal to Teicholz.  It is published on the BMJ website.

HHS also published a statement, reproduced by Mother Jones.

The British Medical Journal’s decision to publish this article is unfortunate given the prevalence of factual errors. HHS and USDA required the 2015 Dietary Guidelines Advisory Committee to conduct a rigorous, systematic and transparent review of the current body of nutrition science. Following an 19-month open process, documented for the public on DietaryGuidelines.gov, the external expert committee submitted its report to the Secretaries of HHS and USDA. HHS and USDA are considering the Scientific Report of the 2015 Dietary Guidelines Advisory Committee, along with comments from the public and input from federal agencies, as we develop the 2015 Dietary Guidelines for Americans to be released later this year.

Yoni Freedhoff’s Weighty Matters blog provides a handy summary of additional responses to the BMJ article.

Scientific analysis of The Big Fat Surprise

Many of the scientific claims in this book seemed so far-fetched that they induced a nutritionist, Seth Yoder, to go over it line by line, read the references, and point out discrepancies.   These are posted on his website in two parts.

A summary quote from Part 1:

What makes this particular book interesting is not so much that it is bad (which it is) or that it is extravagantly biased (which it also is). No, what really fascinates me about this book is that the author excessively and shamelessly lifts other people’s material.

And a quote from Part 2

The Big Fat Surprise (BFS) by Nina Teicholz is yet another book in a long line of books that informs the reader that everything you thought you knew about nutrition is wrong: saturated fat from animals is actually quite good for you, cholesterol isn’t really important, the government lied to you, nutritionists and dietitians lied to you, the American Heart Association lied to you, etc… Leaving aside that the concept of that kind of a conspiracy actually existing is really absurd, what I’m surprised about is that publishers can keep churning out books like this and people are gullible enough to keep buying them.

Caveat emptor.

Additions: 

Jul 28 2015

Trans-Pacific Partnership’s food issues: rice, sugar, Malaysian palm-oil, trans fats

The Trans-Pacific Partnership (TPP) negotiations are taking place this week in Maui, as usual, in deep secret.

Doug Palmer of Pro Politico describes the major food issues: dairy, origin names, pork, rice, and sugar.  The issues come down to market share.  Every country wants to protect its own products but have free access to markets in other countries.

Although not a food, tobacco best explains why the TPP makes people nervous.  US tobacco companies want the TPP to open new markets.  But one of the TPP provisions is said to allow corporations sue governments that pass rules that might hurt the corporation’s business.  Philip Morris sued Australia over its “plain packaging” law and is now suing Great Britain.

The US position is supposedly that a country’s measures  to protect the health of humans, animals, or plants should not be in violation of the TPP, and that challenges to tobacco-control measures should be cleared with TPP partners.   Malaysia, for example, has proposed to exempt tobacco-control measures from challenges under TPP.

Malaysia?

The State Department has just taken Malaysia off its list of the worst countries for human trafficking (see the July 2015 Trafficking in Persons Report).

What a coincidence.  This allows Malaysia to participate in TPP negotiations.

But what bad timing.  The Wall Street Journal has just published a harrowing story about the de facto slavery of palm-oil workers on Malaysian plantations (the New York Times just did one on “sea slaves” forced to fish for pet food or animal feed).

As Rainforest Action Network said of the Malaysia story in a press release:

July 27, 2015 (SAN FRANCISCO) – The Obama administration has removed Malaysia from the list of worst offenders for human trafficking and forced labor today, one day after The Wall Street Journal published an extensive report on human trafficking and forced labor on Malaysian palm oil plantations that directly supply major U.S. companies. Malaysia is one of 12 nations in the contentious Trans-Pacific Partnership trade deal, and inclusion of a country with the lowest ranking in the State Department’s Trafficking in Persons Report would be problematic for the administration.

And then, there’s the trans-fat connection:  The US demand for replacement of partially hydrogenated vegetable oils has pushed Malaysia and other palm-oil countries to produce more palm oil, faster.

The Wall Street Journal explains:

Palm oil has been repeatedly named on the U.S. Department of Labor’s list of industries that involve forced and child labor, most recently in 2014. Activists have blamed palm-oil plantations in Indonesia and Malaysia for large-scale deforestation and human-rights abuses. Oil palm growers respond that the palm tree, a high-yield crop, is a useful tool for socioeconomic development.

palm oil

The TPP is hard to understand, not least because negotiations are secret.  In giving the President the go-ahead to sign the agreement, Congress made two stipulations:

  • Congress must be notified 90 days in advance of signing.
  • The terms of the agreement must be disclosed to the public 60 days prior to signing.

At least that.  TPP deserves very close scrutiny.

Feb 23 2015

Dietary guidelines shouldn’t be this controversial

The uproar caused by the release of the Scientific Report of the 2015 Dietary Guidelines Advisory Committee (DGAC) has been even noisier than I predicted, so noisy that USDA Secretary Vilsack appears to have pulled back on it.  He told Jerry Hagstrom (HagstromReport.com) that:

He wants people to realize that the process of writing the dietary guidelines “is just beginning today,” and that he and [HHS Secretary] Burwell will consider input from federal agencies and the general public. He said he wants to be sure that people “know that I know my responsibility.”

In this, Vilsack was referring to the directive by Congress in the 2015 appropriations bill blocking him from considering sustainability in the guidelines.

As for the DGAC report: It concluded:

…the U.S. population should be encouraged and guided to consume dietary patterns that are rich in vegetables, fruit, whole grains, seafood, legumes, and nuts; moderate in low- and non-fat dairy products and alcohol (among adults); lower in red and processed meat; and low in sugar-sweetened foods and beverages and refined grains.

Predictably, this did not go over well with the meat industry or, for that matter, other industries affected by such advice or groups funded by such industries.

Less predictably, the New York Times published an Op-Ed by Nina Teicholz, the journalist author of “The Big Fat Surprise,” a work based on her own review of the science of fat.  In her view, mainstream nutritionists have badly misinterpreted this science to the great detriment of public health.

Her conclusion:

…we would be wise to return to what worked better for previous generations: a diet that included fewer grains, less sugar and more animal foods like meat, full-fat dairy and eggs.

But Teicholz’ book has been the subject of a line-by-line analysis by Seth Yoder (whom I do not know personally).  Mr. Yoder did what graduate students in science are trained to do: read the references.

He looked up and examined the references Teicholz cites in the book as the basis of her views.  He documents an astonishing number of situations in which the references say something quite different from what Teicholz gets out of them.  At the very least, his analysis raises serious questions about the credibility of her views on the science of fat.

Let’s grant that the science of nutrition is difficult to do and complicated.  The New York Times should know this, which is why I’m surprised that it would give Teicholz so prominent a platform without countering them with point-counterpoint views of a respected nutrition scientist.

It does little to foster the health of the public to make nutrition science appear more controversial than it really is.

The basic advice offered by 2015 Dietary Guidelines Advisory Committee boils down to plain common sense:

  • Eat plenty of foods from plant sources
  • Eat foods from animal sources in moderation
  • Balance calories
  • Avoid overeating junk food

Unfortunately, this kind of advice doesn’t make headlines or, apparently, merit op-ed space in the New York Times.

Jun 18 2014

Time Magazine: “Eat Butter.” Maybe in moderation, please?

I love butter as much as the next person, but when I went to New York’s Food Fest yesterday, the butter makers were all proudly displaying Time Magazine’s provocative June 23 cover.

INTcover0623LR.jpg

The cover story is by Bryan Walsh.

It comes with an even more provacative video–one of those “everything you thought you knew about diet is wrong” things.

I’m quoted in his article, but I wish he had quoted more of my comments about context.

He says saturated fat consumption is down, but heart disease is still the number one killer of Americans.

Yes it is, but not nearly as much as it used to be (as I discussed in a previous post):

Americans must be doing something right.

The big problem is type-2 diabetes.  It’s going up in parallel with obesity: Fat calories and sugar calories contribute to obesity.

The dietary bottom line?  Eat your veggies, balance calories, and stay active.

Really, it’s not more complicated than that.

But that kind of advice will never make the cover of Time, alas.

Addition, June 20: David Katz on how easy it is to misinterpret studies of saturated fat (or sugars for that matter) and health.

Mar 19 2014

Is saturated fat a problem? Food for debate.

What is a poor eater to do?

The latest meta-analysis of the effects of saturated fat on heart disease finds—none.

This study, reported in the Annals of Internal Medicine (doi: 10.7326/M13-1788), examined the results of

  • 32 observational studies involving 530 525 participants
  • 17 observational studies involving 25 721 participants
  • 27 randomized controlled trials involving 103 052 participants

The result?

Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats. 

This meta-analysis follows an editorial in a Mayo Clinic publication (http://dx.doi.org/10.1016/j.mayocp.2013.11.006) by authors who argue that saturated fat is not the problem.  Carbohydrates (e.g., sugars) are the problem.  The authors argue:

  • Effects of saturated fat on blood cholesterol are weak and transient.
  • Meta-analyses have found a lack of an association between heart disease mortality and saturated fat intake.
  • Stroke studies find that patients with stroke had eaten less saturated fat.
  • Long-term studies find that people with the highest dairy consumption have the lowest mortality risk, and also low diabetes and heart disease.
  • Dietary trials find trivial or no benefit at all from decreasing saturated fat and/or increasing intake of polyunsaturated fat.

On this basis, they say that advice to reduce intake of saturated fat is irrational.

The New York Times asked several experts for comment on the meta-analysis, among them Dr. Frank Hu of Harvard:

The single macronutrient approach is outdated…I think future dietary guidelines will put more and more emphasis on real food rather than giving an absolute upper limit or cutoff point for certain macronutrients…people should try to eat foods that are typical of the Mediterranean diet, like nuts, fish, avocado, high-fiber grains and olive oil.

Dr. Hu was referring to a large clinical trial (not included in the meta-analysis), which concluded that a diet with more nuts and extra virgin olive oil reduced heart attacks and strokes when compared with a lower fat diet with more starches.

The Times story contained a reminder that the American Heart Association issued dietary guidelines last year to “restrict saturated fat to as little as 5 percent of their daily calories, or roughly two tablespoons of butter or two ounces of Cheddar cheese for the typical person eating about 2,000 calories a day.”

How to make sense of this?

I vote with Frank Hu that dietary advice should focus on food, not nutrients.

Focusing on one or another nutrient—fat, saturated fat, cholesterol, or sugar—takes foods out of their caloric as well as dietary context.

My guess: If you balance food intake with physical activity and are not overeating, the specific proportion of fat, carbohydrate, and protein won’t matter nearly as much.

While the arguments about fat v. sugar go on and on:  Eat your veggies, vary the foods you eat, don’t gorge, and enjoy what you eat.

Nov 28 2012

The Danish fat tax: reflections on its demise.

My latest publication is a commentary on the reversal of the Danish fat tax in New Scientist, November 26:

Fighting the flab means fighting makers of fatty foods

A YEAR ago in these pages, I congratulated the Danish government on its revolutionary experiment. It had just implemented a world-first fiscal and public health measure – a tax on food products containing more than 2.3 per cent saturated fat.

This experiment has now been dropped. Under intense pressure from the food industry in an already weak economy, the Danish government has repealed the fat tax and abandoned an impending tax on sugars.

Nobody likes taxes, and the fat tax was especially unpopular among Danish consumers, who resented having to pay more for butter, dairy products and meats – foods naturally high in fat.

But the real reason for the repeal was to appease business interests. The ministry of taxation’s rationale was that the levy on fatty foods raised the costs of doing business, put Danish jobs at risk and drove customers to buy food in Sweden and Germany.

In June this year, a coalition of Danish food businesses organised a national repeal-the-tax campaign. The coalition said that fat and sugar taxes would cause the loss of 1300 jobs, generate high administrative costs and increase cross-border shopping – precisely the arguments cited by the government for its U-turn.

We can now ask the obvious questions. Did the tax achieve its aims? Was it good public policy? What should governments be doing to reduce dietary risk factors for obesity?

The purpose of food taxes is to reduce sales of the products concerned. In bringing in its fat tax, the Danish government also wanted to raise revenue, reduce costs associated with obesity-related diseases, and increase health and longevity. A year is hardly time to assess the impact on health, but the tax did bring in $216 million. Danes will now face higher income taxes to make up for the loss of the fat tax.

Business groups insist that the tax had no effect on the amount of fat that Danes ate, although they chose cheaper foods. In contrast, economists at the University of Copenhagen say Danish fat consumption fell by 10 to 20 per cent in the first three months after the tax went into effect. But it is not possible to know whether it fell, and cross-border shopping rose, because of the tax or because of the slump that hit the Danish economy.

A recent analysis in the BMJ suggests that 20 per cent is the minimum tax rate on food to produce a measurable improvement in public health. The price of Danish foods hit by the tax increased by up to 9 per cent, enough to cause a political firestorm but not to make much of a difference to health.

Is a saturated-fat tax good public policy? A tax on sugary drinks would be a better idea. To see why, recall that obesity is the result of an excess intake of calories over what we burn. Surplus calories, whether from carbohydrate, protein or fat, are stored as body fat. All food fats are a mix of unsaturated and saturated fatty acids; all provide the same number of calories per unit weight.

Saturated fats raise the risk of coronary heart disease, although not by much. Trans fats, banned in Denmark since 2003, are a greater risk factor. Because the different saturated fatty acids vary in their risk, imposing a single tax on them as if they are indistinguishable is difficult to support scientifically.

For these reasons, anti-obesity tax measures in other countries have tended to avoid targeting broad nutrient groups. Instead, they focus on processed foods, fast food or sugary drinks – all major sources of calories. Taxing them seems like a more promising strategy.

What else should governments be doing? That they have a role in addressing the health problems caused by obesity is beyond debate, not least because they bear much of the cost of dealing with such problems. In the US, economists estimate the cost of obesity-related healthcare and lost productivity at between $147 billion and $190 billion a year. The need to act is urgent. But how?

One lesson from Denmark is that small countries with open borders cannot raise the prices of food or anything else unless neighbouring countries also do so. But the greater lesson is that any attempt to encourage people to eat less will encounter fierce food-industry opposition. Eating less is bad for business.

In the US, state and city efforts to tax sugary drinks have met with overwhelming opposition from soft-drink companies. They have successfully spent tens of millions of dollars lobbying legislators and convincing the public that such measures deprive voters of their “right to choose” or, as in Denmark, can damage the economy.

What’s more, the poor cannot be expected to support measures that increase food costs, even though obesity-related problems are much more common among low-income groups.

If governments really want to reduce the costs of obesity-related chronic diseases, they will have to address the problem at its source: the production and marketing of unhealthy food products.

A review by the American Heart Association cites increasing evidence for the benefits of anti-obesity interventions: food taxes, subsidising healthy foods, media campaigns to promote exercise and good diet, restrictions on portion sizes, and restrictions on the marketing of unhealthy foods and their sale in schools.

Governments must decide whether they want to bear the political consequences of putting health before business interests. The Danish government cast a clear vote for business.

At some point, governments will need to find ways to make food firms responsible for the health problems their products cause. When they do, we are likely to see immediate improvements in food quality and health. Let’s hope this happens soon.

Marion Nestle is the author of Food Politics and What to Eat and is the Paulette Goddard professor of nutrition, food studies, and public health at New York University

Nov 21 2012

Mon dieu. The French “Nutella tax.”

Not to worry.  This is just a proposal.

A French Senator wants the country to impose a 300% increase in the tax on palm oil imports, thereby raising the price of products containing it—like Nutella, the chocolate-hazelnut spread beloved by European children (and adults).

Of course they love it.  The first ingredient is sugar.

But the second ingredient is palm oil, high in saturated fats.  Palm oil production, again alas, is strongly linked to deforestation and other environmental problems in Malasia and Indonesia.

The proposed tax distresses Malasian palm oil producers:

The action…to propose onerous new burdens on palm oil producers, is irresponsible, badly-informed and ignores the primary source of saturated fats in the French diet [referring to trans fats].

The proposed tax also distresses the makers of Nutella, as well it should.  Most Nutella eaters probably think they are eating hazelnuts and chocolate.  It must come as an unpleasant surprise to learn that the first two ingredients are sugar and palm oil.

At a meeting in Boston this week, Joe O’Toole, the president of Lucullus, a French specialty food company, brought me the November 16 edition of Le Figaro.  He knew I’d want to see the two-page ad defending Nutella’s use of palm oil.

My rather loose translation:

Nutella, you are delicious but why do you have palm oil?

Let’s talk about palm oil.

For 50 years, the French have trusted us to be an important brand.  This is an important responsibility.  This is why we have always made responsible choices in our selection of ingredients.

Today, Nutella finds itself in an unjust position at the heart of a debate about palm oil….Palm oil gives smoothness (“l’onctuosité”) and stability to the recipe.

…Contrary to certain ideas and opportunistic communications…palm oil is not dangerous to health. Nutritionists say…Nutella contains less saturated fat than most snacks or breakfasts.

At the bottom of both pages, the ad says: “For your health, eat at least five fruits and vegetables per day.”

Oh.  OK. [It turns out that the French government requires this statement on all food ads.]

Nutella’s website has a Q and A.  For example:

How can Nutella® help moms at breakfast time?

It can be difficult to persuade children to eat breakfast. When used in moderation with complementary foods, Nutella® is a quick and easy tool to encourage kids to eat whole grains, such as whole wheat toast, English muffins, toaster waffles and bagels.

The chocolate milk argument!  It sounds better in French, no doubt.

Update, November 23: Thanks to Lucie for finding this annotated, alternative version of the ad.

 

 

 

 

 

 

 

 

 

Aug 5 2012

Low carb or low fat: Do calories count?

Here’s my once a month on the first Sunday Food Matters column for the San Francisco Chronicle, out today:

Nutrition and public policy expert Marion Nestle answers readers’ questions in this column written exclusively for The Chronicle. E-mail your questions to food@sfchronicle.com, with “Marion Nestle” in the subject line.

Q: I’m confused about calories. If I cut calories to lose weight, does it matter what foods I eat? Or are all calories the same?

A: As the co-author of “Why Calories Count: From Science to Politics,” I hear this question all the time.

The short answer: Calories matter for weight. The choice of foods that provide the calories matters a lot for health and may make it easier for you to diet successfully.

To lose weight, reducing calorie intake below expenditure works every time.

To prove this point, a professor at Kansas State University lost 27 pounds in 10 weeks on the Twinkies diet – one Twinkies every three hours with occasional snacks of chips, sugary cereals and cookies. Even so, he cut his usual calorie intake by 800 a day. Anyone would lose weight doing that.

Only four dietary components provide calories: fat (9 per gram), carbohydrate and protein (4 per gram each) – and alcohol (7 per gram).

Does the particular mix of these components make any difference to weight loss? Yes, say proponents of diets low in carbohydrate, especially rapidly absorbable sugars and refined starches.

Low-carbohydrate diets are necessarily high in fat, and somewhat higher in protein. Do people lose weight on them because of the effects of carbohydrates on insulin levels or because low-carbohydrate diets help reduce calories?

This question does not have an easy answer, but not for lack of trying. Weight-loss studies are hard to do. Estimating calorie intake is notoriously inaccurate, and measuring calories is difficult and expensive.

The first measurement study I know of took place in 1964. Investigators from the Oakland Institute for Medical Research studied weight loss in five obese patients in a hospital metabolic ward. They calculated the number of calories needed to induce rapid weight loss in each patient, and fed each of them a liquid formula diet containing that number every day. Every few weeks, they changed the formula to vary the proportions of protein (ranging from 14 percent to 36 percent of calories), fat (12 percent to 83 percent), and carbohydrate (3 percent to 64 percent).

Regardless of the proportions, all patients lost weight at a constant rate. The investigators titled their study “Calories Do Count.”

This study was conducted under rigidly controlled conditions of hospitalization and involved actual measurements – not estimations – of calorie intake and body weight.

But what about weight-loss studies involving people who are not incarcerated? Since the early 2000s, numerous clinical trials have shown low-carbohydrate diets to produce greater weight loss than low-fat diets. Some also have observed improvements in blood pressure, blood glucose levels and blood lipids.

But it is so inaccurate to estimate calorie intake in such studies that most didn’t bother to try. This means they can’t say whether the weight loss was due to composition of the diet or to calorie reduction.

It’s possible that low-carbohydrate, high-fat diets make people less hungry, but the evidence for this is mixed. Most studies of extreme diets of any type report high dropout rates or failure to stick to the diet for more than six months or so. And even though initial weight loss is rapid on low-carbohydrate diets because of water loss, these diets are low in fiber and some vitamins.

One problem with losing weight is that it takes fewer calories to maintain smaller bodies. Dieting also reduces energy expenditure.

One recent study of that problem involved taking detailed measurements for several years, and illustrates the difficulties of obtaining definitive answers to questions about diet composition and energy balance.

The researchers wanted to know whether diet composition affected energy expenditure in very obese people who had just dieted off up to 15 percent of their weight. They found that a low-carbohydrate diet did not slow down energy expenditure nearly as much as a low-fat diet, meaning that low-carbohydrate diets might make it easier for people to maintain weight loss.

On this basis, the investigators said, “The results of our study challenge the notion that a calorie is a calorie from a metabolic perspective.”

Perhaps, but study subjects were fed prepared calorie-controlled diets for only four weeks, and lost and maintained weight under highly controlled conditions. Does diet composition matter for weight maintenance in the real world? Longer-term studies by other investigators show that diet composition makes little difference in the ability to maintain weight loss.

Most reviews of the subject conclude that any diet will lead to weight loss if it cuts calories sufficiently.

Obviously, some diets are better for health than others.

Face it. The greatest challenge in dieting is to figure out how to eat less – and to eat healthfully on a regular basis – in the midst of today’s “eat more” food environment. And that’s a much more important research problem than whether low-carbohydrate or low-fat diets work better for weight loss.

Marion Nestle is an author and a professor in the nutrition, food studies and public health department at New York University. She blogs at foodpolitics.com. E-mail: food@sfchronicle.com