by Marion Nestle

Currently browsing posts about: Dietary-Guidelines

Nov 21 2024

Benefits of the dietary guidelines: resources

DietaryGuidelines.gov provides handouts on Food Sources of Select Nutrients.

Alas, calories are not among these handouts, even though 75% of American adults are now considered overweight or obese.

These are meant for nutrition professionals but are fun to see if you want to see what they get.

The page lists lots of other resources.

Will these help you make healhier dietary choices?

Nutrients are not the problem; calories are the problem.

To do something about them, we need a healthier food environment.

I wish the USDA would give that as much attention as it gives nutrients.

Nov 20 2024

Can Robert F. Kennedy, Jr influence the Dietary Guidelines? Most definitely, yes.

The 2025-2030 Dietary Guidelines Advisory Committee (DGAC) report is well underway.   The committee either has submitted or is about to submit its report to HHS and USDA;.  The report has not yet been posted, but presumably will be posted soon.

But understand: the scientific advisory committee is just that: advisory.

The agencies, HHS and USDA, are responsible for writing the actual guidelines.  They choose an internal committee to do that work.  That new committee can pick, choose, add, or subtract from the advisory committee’s report.

So yes, the new Secretaries of HHS and USDA can have a lot of input (and veto power) into the new guidelines.

As I’m fond of repeating, the guidelines process was quite different when I was on the DGAC in 1995.  Then, our committee chose the research topics, reviewed the research, wrote the advisory committee report, and wrote the actual dietary guidelines.  The agencies made only minor tweakings.

The agencies have written the guidelines since 2005, making the process much more subject to politics.

The DGAC, for example, viewed the evidence on ultra-processed foods as too limited to take a stand, yet RFK, Jr says ultra-processed foods are killing us.

The development of the 2025-2030 guidelines will be most interesting to watch.  Stay tuned.

Oct 30 2024

The Dietary Guidelines saga continues: II. The same old recommendations

Every five years since 1980, we get to go through the most enormous fuss about dietary guidelines that have not changed in any fundamental way since then.

Then and now, they say eat more vegetables, balance calories, and reduce intake of foods high in sugar, salt, and fat.

You don’t believe me?  Here is the much more straightforward 1980 version.

Reminder: The Dietary Guidelines Advisory Committee is just that: advisory.  The agencies will write the actual guidelines.  Until the guidelines actually appear, everything remains speculative.  They are due to appear by the end of 2025.  Between now and then, we have an election to deal with.  No matter who wins, political appointees in the two sponsoring departments will change and could greatly intervene.

I love the Dietary Guidelines.  They are endlessly entertaining examples of food politics in action.

Oct 29 2024

The 2025-2030 dietary guidelines saga continues: I. the non-recommendations

The current Dietary Guidelines Advisory Committee has produced its draft recommendations.  These, as I discuss tomorrow, are mostly banal, much the same as all guidelines since 1980.

But this year there are two rather shocking exceptions, both having to do with what is not recommended.

Incredible non-recommendation #1.  Reduce the focus of the Dietary Guidelines on reduction of chronic disease risk.

What???  The entire purpose of the Dietary Guidelines is to reduce the risk of diet-related disease.  Chronic diseases—obesity, type-2 diabetes, heart disease, cancer, etc—are the leading causes of death and disability among U.S. adults.

Maybe this was a typo?  Surely this committee means to say “Recommend increasing the focus of the Dietary Guidelines on chronic disease risk reduction.

The current wording is a travesty.  I’m not the only one who thinks so.  See Jerry Mande’s Tweet (X).

Update: I gather the uproar over this did some good and the committee is changing the wording.

Incredible non-recommendation #2.  Say nothing about ultra-processed foods.

The committee made it clear that they were not going to say a word about ultra-processed foods.  At least not now.  Why not?

Scientific experts tasked with advising federal officials drafting the 2025-2030 Dietary Guidelines for Americans said the data were far too limited to draw conclusions…Ultra-processed foods don’t have a recognized definition or a robust body of scientific literature that has studied them, they said, so guidelines would be premature.

Another travesty.  An overwhelming body of observational research suggests harm from diets high in ultra-processed foods.  OK, these studies only demonstrate association, not causation.

But—not one, but two well-controlled clinical trials demonstrate that ultra-processed foods induce people to consume more calories than they would otherwise: 500 more in one trial and more than 800 in the second.  These are enormous differences.

Yes, it would be great to know why, exactly.  And yes, the definition of ultra-processed can be fuzzy with respect to a few—remarkably few—foods.

But what more do you need to know?  Isn’t this enough to tell people that if they want to keep caloric intake under control, a good way to do that would be to limit consumption of ultra-processed foods?

But this committee chose to ignore the controlled trials because they didn’t last long enough.

As I explain in that link, the committee’s hands are tied by having to make “science-based” recommendations.  But in nutrition, most of the science is observational, which is why those controlled trials, short in duration as they are, matter so much.

The committee needs to revisit this decision.  If the guidelines do not include a recommendation to limit intake of ultra-processed foods, they will be ignoring the science and will be behind the times.

Worse, the guidelines will not help Americans reduce their risks for chronic disease.

See: Stat News:  5 questions about the next U.S. dietary guidelines, and the ‘impossible restriction’ on them: Difficulty of nutrition research leaves problems like ultra-processed foods largely unaddressed. 

Tomorrow: the banality of the latest recommendations.

Jun 6 2024

Dietary guidelines III. They haven’t changed since the late 1950s

Despite all the fuss about the guidelines every five years, they say the same things every time: eat more fruits and vegetables (plant foods), balance calories (good luck with that), and reduce intake of saturated fat, sugars, and salt (euphemisms for ultra-processed foods).

You don’t believe me?  Take a look:

Ancel and Margaret Keys’ 1959 dietary guidelines for prevention of coronary heart disease.*

  1. Do not get fat, if you are fat, reduce.
  2. Restrict saturated fats, the fats in beef, pork, lamb, sausages, margarine, solid shortenings, fats in dairy products.
  3. Prefer vegetable oils to solid fats, but keep total fats under 30% of your diet calories.
  4. Favor fresh vegetables, fruits, and non-fat milk products.
  5. Avoid heavy use of salt and refined sugar.
  6. Good diets do not depend on drugs and fancy preparations.
  7. Get plenty of exercise and outdoor recreation.
  8. Be sensible about cigarettes, alcohol, excitement, business strain.
  9. See your doctor regularly, and do not worry.

*Keys A, Keys M.  Eat Well and Stay Well.  New York: Doubleday & Co, 1959.

The concept of ultra-processed foods encompasses much of this.  We would be better off eating less of them.

It shouldn’t take all this work every five years to come to this conclusion.

So why all the fuss?  I’d call it food politics.

If people ate healthfully, chronic disease prevalence would decline and lots of industries would be out of business: junk food, diet foods, diet drugs, and those profiting from health care.

Jun 4 2024

Dietary guidelines I. Ultra-processed foods

I don’t like writing about the dietary guidelines process while it is still ongoing because so much can change between now and the time the advisory committee submits its report, and USDA and HHS issue the actual guidelines.

But this Dietary Guidelines Advisory Committee is dealing with the concept of ultra-processed foods and is tied in knots over it.

So I will devote this week to the guidelines.

  • Today: Why knots?
  • Wednesday: Why isn’t NIH funding more rigorous nutrition research?
  • Thursday:  Why all the fuss when guidelines always say the same things?

OK.  Let’s get to it.

Why do I think the Dietary Guidelines Advisory Committee (DGAC) is tied in knots over ultra-processed foods (UPF)?

  1. It  is required to make evidence-based recommendations.  This is impossible with observational evidence.
  2. It is required to exclude the one existing controlled clinical trial from consideration (because it was too short).

Therefore, it had to conclude: ““Limited evidence suggests that dietary patterns with higher amounts of foods classified as UPF consumed by adults and older adults are associated with greater adiposity (fat mass, waist circumference, BMI) and risk of obesity/overweight. Evidence Grade: Limited.”

The DGAC is in an impossible position, and doing the best it can under the circumstances.

I need to say a word about evidence-based recommendations.  How I wish they could be.   If all you have is observational studies, you need to interpret them carefully.  Interpretation is subject to bias.

When I was a DGAC member (1995 guidelines), the agencies recognized what we were up against.  They instructed us to review the available research and give the best advice we possibly could based on it.

All of this raises a philosophical question: Should government agencies issue advice based on incomplete and inadequately controlled observational research?  Or should they say nothing?

This committee, apparently, is considering saying nothing about ultra-processed foods: “It would be hugely problematic to tell people to avoid 60% of the food supply without having something good to replace it.”

Really?  Plenty of “something good” is available.  It’s called food: fruits, vegetables, grains, meat, fish, dairy, eggs.

These—unprocessed and minimally processred—can be delicious, nutritious, and satisfying, and at reasonable cost.

—–

Tomorrow: Why don’t we have more rigorous research?

Addition:  The video of the meeting.  The discussion of ultra-processed foods starts at 3:51:45 .

Feb 23 2024

Weekend reading: FAO calls for food systems-based dietary guidelines

The U.N.’s Food and Agriculture Organization (FAO) is taking the lead on bringing dietary guidelines into the 21st Century.

It is calling for national dietary guidelines not only to be nutrient-based and food-based, but food systems-based.

Food systems-based guidelines extend beyond food-based guidelines that “provide advice on foods, food groups and dietary patterns to provide the required nutrients to the general public to promote overall health and prevent chronic diseases.”

Food system-based guidelines not only address health and nutritional priorities but also consider sociocultural, economic, and environmental sustainability factors.  This means

context-specific multilevel recommendations that enable governments to outline what constitutes a healthy diet from sustainable food systems, align food-related policies and programmes and support the population to adopt healthier and more sustainable dietary patterns and practices that favour, among other outcomes, environmental sustainability and socio-economic equity.

This is a huge advance.  It means that sustainability issues are essential components of dietary advice.

From now on, dietary guidelines that do not consider sustainability are out of date.

Note: By order of Congress, the 2015-2020 Dietary Guidelines did not consider sustainability in its meat recommendations and sustainability was off the table for the 2020-2025 Dietary Guidelines and also for the 2025-2030 version now underway.  This means the new guidelines issues in 2025 will be dated and largely irrelevant to the modern era.

Unless the Advisory Committee gets to work.  I hope it does.

Dec 7 2023

No, Virginia, correlation does not necessarily signify causation

On Thursdays I like posting things I want everyone to enjoy.

This one, I stole from Tamar Haspel, who writes about food for the Washington Post.

I follow her on X (the site formerly known as Twitter), where she recently posted:

This could be my all-time favorite BMI correlation!

In China and post-Soviet states, BMI correlates with corruption. The fatter, the crookeder.

The correlation she cites is from an article in the Economist, Are Overweight Politicians Less Trustworthy?

 

 

 

 

 

 

 

 

 

I agree.  This is a fabulous example of how correlation does NOT mean causation—a basic tenet of epidemiology often forgotten.

But here’s my personal favorite example.  I laugh every time I see it.

Image

No, the Dietary Guidelines did not cause the prevalence of obesity to rise.

This is correlation, NOT causation.

For causes, please consider food overproduction, pressures on food companies to sell food when there is so much of it, and the shareholder value movement, which demands not only profits, but  continual growth in profits.  All of these forced food companies to find new ways to get everyone to eat more food (by creating an “eat more” food environment.  I discuss all this in Food Politics and my other books).

Correlation is lots of fun but causation requires much deeper analyses.

Sorry about that.

Thanks Tamar.