More beans, peas, lentils: A nutrition expert's take on new guidelines

Every five years the U.S. government releases an updated set of its Dietary Guidelines for Americans. The report, the first of which was issued in 1980, relies on the best available nutrition science to recommend dietary choices that promote health and prevent chronic disease.

While the main purpose is to guide school lunch menus and other government assistance programs, it also provides perhaps the clearest summary of the current state of nutrition science and reveals conclusions that underscore the need for Americans to better apply that science.

"We still eat much too much refined grain, much too little whole grain," said Christopher Gardner, PhD, the director of nutrition studies at the Stanford Prevention Research Center.

To ensure the work reflects the best recent scientific research, the Health and Human Services and the U.S. Department of Agriculture assembled a team of 20 top nutrition scientists with a spectrum of subspecialties. The volunteer researchers collaborated in an intensive evaluation of recent science. The product of their work, a 421-page-long set of recommendations, was released last week and will serve as scientific guidance for the guidelines.

Gardner, the Rehnborg Farquhar Professor and a professor of medicine, was recruited in January 2023 to serve on the 2025 Dietary Guidelines Advisory Committee. He and his colleagues recently emerged from the two-year process, and he agreed to talk about the science, politics and health equity issues behind the government's bottom line on what is -- or should be-- for dinner in America.

If you had to boil down the most substantive recommendation for change of your scientific committee to one sentence...

Easy: Eat more beans, peas, and lentils and less red meat.

Easy: Eat more beans, peas, and lentils and less red meat.

Christopher Gardner

How has the process evolved?

The process has become a lot more transparent. Our meetings were all open to the public. It was an honor to be part of such an objective, open and careful process. The information in the report has evolved, as have the methodologies and the ways we present the results. But the aims are the same: to review the best science and make recommendations based on it.

How have the recommendations changed over the decades?

The guidelines have evolved from a focus on nutrients to a focus on foods. In 1980 we were still thinking in terms of nutrients, asking, "What does sodium do? What does protein do? What does cholesterol do?" And then, in 2015, the focus shifted to foods, because people don't eat nutrients, they eat food.

Instead of asking, "Is too much cholesterol bad?" the committee asked, "Are too many eggs a problem?" This was a big step. In the current report, much of the emphasis is on identifying the main components of an overall healthy dietary pattern, in terms of what to emphasize and what to limit or avoid.

Thinking in terms of food patterns is a longtime focus for you. What were some of the committee's conclusions about patterns of eating?

One overarching conclusion -- which was wildly satisfying for me -- was that switching one type of animal-sourced food for another had limited or negligible evidence for benefit (e.g., high fat meat or dairy for lower fat meat or dairy). The larger and more observable impact came from switching from red meat over to beans, peas, lentils, veggies and grains. Another strong effect came from replacing butter with any kind of plant oil, including even the "hateful eight" seed oils -- canola, corn, cottonseed, soybean, sunflower, safflower, grapeseed, and rice bran oils -- which are high in omega-6 fatty acids. These have been mistakenly associated with harmful oxidation and inflammation, when in fact the evidence for effects of this substitution supports a health benefit.

By choosing lean meat you might be eating less saturated fat. But if you eat plants instead, you not only get less saturated fat, you also get much more fiber. And that makes a huge difference.

Another example of how presentation matters: In earlier guidelines, if you looked at recommended sources of protein, the list started with lean beef and ended with beans. For years, so many Americans have assumed that you must eat meat to get protein. But our committee recommends that the protein category should start with beans, peas and lentils and move lean meat to the end of the list. In terms of messaging, that's a big deal.

More on diet and nutrition

Talk about how health equity factored into your recommendations.

We would evaluate all the literature on a certain subject -- healthy dietary patterns and cardiovascular disease, for example -- and talk it over as a group. At the end we would have to say whether the evidence pointed in one direction or another; whether it suggested a conclusion about a meaningful association; and, if so, what that conclusion was. Generalizability was an important consideration. Did the studies include both men and women? Did they include different racial and ethnic groups. Did they consider different socio-economic positions?

In the end, quite a few of our conclusions were downgraded on generalizability. We couldn't confidently say that for all people of all races, sexes, ethnicities and economic circumstances "If you eat x, then y is a probable result." We can't say an association is strong for all Americans when the studies have only been done in populations with limited diversity.

Can you give an example?

For the last two rounds of guideline updates, the association between a healthy dietary pattern and less heart disease has been strong. So, we considered not even looking at it again. But when we asked if there was more health equity information in recent studies, we found a bunch of new studies that took socio-economic position as well as race and ethnicity into account. We said, "Now, this is the kind of data we want!"

We said, "Now, this is the kind of data we want!"

Christopher Gardner

The previous "healthy dietary pattern" included vegetables, fruits, nuts, grains, seeds, low-fat dairy, and limited red meat, sugar, sodium and saturated fat. Our recent assessment of studies with greater representation of different racial and ethnic groups, included a lot more people with lactose intolerance. And for those subjects, the patterns that were most healthy for the heart often did not include dairy. Therefore, the updated recommendation takes dairy out of the primary list, and moves it to a separate line that explains that some studies suggested it was OK for some people to include dairy.

So, the recommendations are getting more helpful to apply to more diverse populations?

As we see more race and ethnicity data, this is one of the things that will happen. We can avoid telling an Asian American who is lactose intolerant to include dairy in their eating patterns, and having them scratch their head and say, "You want me to eat dairy?"

Does the focus on generalizability incentivize researchers to weave race and ethnicity, socio-economic position, and gender into their work in coming decades?

Yes! We're saying, "Hey researchers and funders, don't do or support research if it ignores questions of health equity!"

Part of the committee's assignment is to consider how Americans are doing nutrition-wise now. Are we doing better or worse than five years ago?

A summary and evaluation of what we eat In America, or WWEIA, is a major part of the assessment. And we're still doing horribly! We still eat much too much refined grain, much too little whole grain. We still don't eat enough vegetables or fruits. We still eat more than enough protein, but we're getting only half the recommended amount of fiber. There is a lot of work to be done, and this will take more than just revised dietary guidelines. It will require revamping much of the current overall food system -- including shifts in what foods farmers and ranchers produce (e.g., less beef, more beans, peas and lentils), how they are produced, how they are processed, and how they are distributed.

What's your favorite way to eat peas, beans and lentils?

I have so many! There's hummus in a Mediterranean-style diet and chana masala in an Indian diet. Beans and rice in Latin American diets. Tofu or tempeh in Asian stir-fry. An Italian minestrone soup. And gado gado, peanut sauce salad, in Indonesia. All of those are unapologetically delicious staple dishes in cultures around the world.