Rethinking Health Metrics Before MAHA's Big Reveal

In a few months, we will receive the MAHA Commission report on the connection between our diet and chronic illness, along with their recommendations that are ultimately intended to influence federal guidelines and, most importantly, SNAP funding. How will we know whether their recommendations improve our health? More to the point, what measures can we use now to understand the connection between diet and chronic illness?

For this, we might consider a medR_xiv preprint (a study not yet peer-reviewed) that utilizes the Healthy Eating Index (HEI) to categorize “healthy eating.” Before jumping in, a quick acronym review.

Decoding the Jargon

• The Dietary Guidelines for Americans (DGA) establish the federal government’s official nutritional guidance. They are generated every five years by the USDA and HHS and will be the subject of the MAHA Commission recommendations.
• The Healthy Eating Index (HEI) measures how well a given diet aligns with the DGA on a scale from 0 to 100, with 100 representing perfect alignment. It measures adherence to the DGA
• Supplemental Nutrition Assistance Program (SNAP) delivers the goods, providing financial assistance to low-income individuals and families for purchasing food. SNAP is federally mandated to promote nutrition in line with the DGA. It excludes alcohol, hot prepared food, and supplements. The debate over the continuation of allowing sugary beverages is ongoing, and it is anticipated that “ultra-processed foods” (UPFs) will now be considered for exclusion.

What the Study Measured

Over the years, there have been bipartisan calls for monitoring the quality of diets and the impact of federal programs. HEI is frequently used as a metric for the efficacy of SNAP, or, for that matter, any diet promoting healthy eating, which is MAHA’s mantra. The importance of this study lies in how well their HEI categorization reflects a healthy diet and the associated risk of chronic illnesses, particularly diabetes, obesity, and cardiovascular disease, all of which are closely tied to diet.

The study also incorporates sociodemographic factors, including education, income, race, ethnicity, and food insecurity, “the limited or uncertain availability of nutritionally adequate and safe foods or limited or uncertain ability to acquire acceptable foods in socially acceptable ways.” Consider these factors part of an obesogenic environment. 

Using data from our old friend, the National Health and Nutrition Examination Study (NHANES), and two 24-hour food recalls (one conducted in person and the second over the phone), researchers created four diet quality categories that reflect the eating patterns of approximately 22,000 adults over 20 years old. 

• High diet quality (HEI >70-100)
• Marginal diet quality (HEI >60-70)
• Low diet quality(HEI >50-60)
• Very low diet quality (HEI 0-50). 

A high-quality diet, as you would anticipate, “includes adequate vegetables, fruits, whole grains, low- and non-fat dairy, and low-fat protein, including beans and nuts, and limits consumption of added sugar, sodium, and saturated fat.”

Data Revelations

Despite years of education, the transformation of our food pyramid into a food plate, regulations on labels, public service announcements, taxes on sugary beverages, and various marketing forces, the average HEI for adults was 56, just slightly above very low diet quality. While roughly a third of us had a high or marginal diet quality, two-thirds of us clearly are not “getting with the guidelines.” 

When those survey results were transformed into “usual dietary intakes,” 86% of us had low or very low diet quality, and there had been no significant improvement over the 10-year NHANES cycles reviewed. Despite the efforts of scientists and lobbyists on all sides of the nutritional special interests, Americans often ignore the government’s nutritional guidance. All the consternation over the diet of SNAP beneficiaries neglects to consider that all of us eat just as poorly.  

An Obesogenic Environment

Of course, changing dietary quality has its sociodemographic fellow travelers. Among the more likely to have high diet quality were:

• Older adults
• Women
• Adults with a college education
• Married or partnered adults
• Those with greater than 200% of the federal poverty level in income
• The food secure

Interestingly, adults born outside of the US were nearly twice as likely to have high diet quality (19.2% vs 11.5%); and employment status resulted in no significant difference in diet quality which may speak to the general efficacy of our SNAP programs as well as our ignoring of the DGA as a nation. 

This polar diagram illustrates how food choices varied in terms of dietary quality. Lines further apart reflect greater differences. Whole grains, whole fruits, greens, and beans demonstrated the greatest disparities. They are also significantly expensive and often difficult to access. High diet quality was associated with the highest intake of minimally processed foods, while very low diet quality was associated with the highest intake of ultra-processed foods. 

These energy-dense UPFs also contributed to about a 124-calorie/day increase in total energy intake among those with very low diet quality. That greater calorie intake, with no change in exercise, might contribute to up to 2 pounds of increased weight a month. So unsurprisingly, a high-quality diet was associated with a lower BMI. However, 27.3% of adults eating a high-quality diet were obese, so nutrition is not the only factor in that “chronic illness.”

More importantly for the MAHA agenda, cardiometabolic biomarkers predictive of diet-related chronic illness varied with dietary quality. Although the differences were statistically significant, their clinical significance remains unclear.

• HDL, the presumptively “good” cholesterol, was higher with high diet quality. LDL, the “bad” cholesterol, showed no differences across the categories. Whether the use of statins influenced this is unknown.
• 43% of adults with high dietary quality had elevated fasting glucose levels compared to 47.7% with very low dietary quality. This suggests that the role of diet, in addition to being only one factor in the “cause” of disease, may not be as significant a driver as MAHA would like us to believe. 

Policy versus Reality

Taken as a whole, these findings suggest that our dietary choices are just one of several factors contributing to an obesogenic environment. The recommendations of the MAHA Commission should be ecological in their scope, rather than focusing on just one driver, diet, with an ill-measured and frankly small impact.

The researchers end on this cherry note:

“In this study, more healthful diet quality categories were associated with a healthy weight status, lipid profile, and glycemic control in a dose-response manner. This is consistent with meta-analyses of prospective observational studies, which found that individuals who score at the top quintile of diet quality for their population have lower risks of all-cause mortality, cardiovascular disease, cancer, and type 2 diabetes compared to individuals who score in the bottom quintile.”

If You Can’t Measure It…

The Healthy Eating Index may not be perfect, but it appears to be the best mirror we currently have for assessing our national diet, and its reflection isn’t flattering. As MAHA prepares to rewrite the playbook on food policy, this study serves as a stark reminder that we must measure our work if we are to detect meaningful change. I will give the last word to noted nutritionist Yogi Berra,

“If you don’t know where you are going, you’ll end up someplace else.”

 

Source: Understanding Sociodemographic And Dietary Determinants Of Cardiometabolic Risk: Cross-Sectional Evidence From The US Healthy Eating Index To Inform Diet Quality Categories MedR_xiv DOI: 10.1101/2024.06.04.24308443