Carbohydrate Food Quality Score: A holistic approach to quantify carbohydrate food quality

Despite the broad diversity of the U.S. population, dietary recommendations often overlook the positive contributions of cultural foods to build healthy dietary patterns. This is especially true when it comes to carbohydrate food guidance, where prevailing approaches have historically focused on only three components-; carbohydrates, sugar, and dietary fiber-;ignoring other important nutrient and cultural considerations. However, a new paper published in Nutrients highlights a more holistic approach, called the Carbohydrate Food Quality Score (CFQS), that is more culturally inclusive and aligns closer with the Dietary Guidelines for Americans.

Unlike other approaches to evaluating carbohydrate quality, the CFQS evaluates the contribution of both under-consumed dietary components like potassium, dietary fiber and whole grains, and overconsumed nutrients like sodium, predominantly found in carbohydrate-containing foods, especially grains. This nuance is significant, as it sheds light on the fact that carbohydrate-containing foods contain many important nutrients beyond carbohydrates. Furthermore, this tool is the only carbohydrate quality index that aligns with the Dietary Guidelines for Americans."

Judy Rodriguez, PhD, RDN, Professor Emerita, Department of Nutrition and Dietetics, University of North Florida, and coauthor of the study

How It Works

The development and validation of the CFQS is described in two previously published articles. In brief, this new system is based on similar foundations of previously published approaches that focus on fiber, sugar and total carbohydrate content of foods. However, CFQS also acknowledges the heterogeneity, nutrient and cultural diversity across the carbohydrate food category by:

1) Including other nutrients like sodium, potassium, and whole grain (for grain-based foods) in the scoring system.

2) Creating two distinct scoring systems: one for non-grain foods (CFQS-4), and one for grain-based foods (CFQS-5). CFQS-4 is scored on a 4-point scale based on the amounts of carbohydrates, sugar, sodium and potassium. CFQS-5 is scored on a 5-point scale, using the same 4 components as CFQS-4, plus whole grains.

"The new CFQS clearly recognizes that carbohydrate foods are not homogenous, and nuance is needed when communicating this to consumers. For example, while potatoes and grain-based foods are considered 'carb foods' and contribute important nutrients to the diet, their nutrient profiles and quality vary. The CFQS can help identify those foods that can be chosen frequently as dietary staples," stated Dr. Rodriguez.

Not only do the metrics help to clarify and quantify carbohydrate food quality, but they also support health equity among all Americans as they can be applied across a variety of budgets, lifestyles, and cultures.

Why it matters

Dietary guidelines continue to emphasize the importance of total dietary patterns and overall diet quality. However, many tools intended to help people build healthy dietary patterns continue to categorize individual foods as 'good' or 'bad'. The CFQS is meant to break this cycle by providing a spectrum of carbohydrate food choices rather than assigning binary classifiers to food choices (e.g., good/bad, eat/avoid) and simplistic food classifications such as 'eat a rainbow' (e.g., dark green, red and orange, etc.) While such systems can be helpful, they are confusing when it comes to foods with neutral colors such as white cauliflower, daikon, jicama, potatoes, brown mushrooms, and black beans. Not only can the CFQS help eliminate confusion, but it aligns with the Dietary Guidelines for Americans as it recognizes other essential nutrients that are under- or over-consumed in the American diet and predominately delivered through carbohydrate-containing foods.

"The CFQS provides a vehicle that affirms with each individual's values, socioeconomics, and food and cultural traditions, and provides a scale to help address nutritional concerns about the diet," explained Julie Miller Jones, PhD, LN, CNS, professor emerita in the Department of Family, Consumer and Nutritional Sciences at the St. Catherine University in St. Paul, and coauthor of the study. "The CFQS can reassure consumers of the role of carbohydrate foods for constructing healthy eating patterns and while affirming equitable, nutritious, and culturally appropriate food choices to influence health."

Disclosures: The Quality Carbohydrate Coalition (QCC) is a multi-stakeholder engagement of commodity groups across the food industry. Guided by the work of its Scientific Advisory Council (SAC), this group aims to support a collaborative, scientific dialogue around the unique and diverse roles that carbohydrate-containing foods play in healthful eating.  The council is made up of six world-renowned experts in carbohydrate research, nutrient profiling, cultural competency and epidemiology: Judith Rodriguez, PhD, RDN; Adam Drewnowski, PhD; Julie Miller Jones, PhD, LN, CNS; Joanne Slavin, PhD, RDN; Siddhartha Angadi, PhD; and Yanni Papanikolaou, MPH.  Potatoes USA provides the funding to support the research being conducted by the SAC.

Additional details on study design, strengths, and limitations

Three one-day menu models were developed to demonstrate the utility of the CFQS models when selecting carbohydrate foods as part of a healthy dietary pattern. Menu models adhered to nutritional requirements outlined in the following dietary patterns established by the 2020-2025 Dietary Guidelines for Americans:

• Healthy US
• Healthy Mediterranean-Style
• Healthy Vegetarian

A fourth menu model was developed in alignment with the USDA Thrifty Food Plan to demonstrate the utility of the CFQS in budget-conscious healthy eating.

All four menu models were created using ESHA Food Processor menu modeling software, and each menu adhered to a 2,000 kcal diet including three meals and two snacks. While carbohydrate foods with a CFQS of three or greater were prioritized, scores of one and two were also included to demonstrate their nutritional contributions to healthy, diverse, affordable and culturally appropriate food patterns.

Finally, four tables were created to reflect carbohydrate foods commonly found across the largest recorded ethnic groups in the United States:

• African American
• Latino/Latin America
• Asian American
• Native American

The purpose of these tables was to demonstrate how culturally inclusive food patterns can be integrated with DGA-recommended dietary patterns and the CFQS models.

The present modeling exercises demonstrate the feasibility of using carbohydrate food quality score models (CFQS-4 and CFQS-5) to better understand the value and variability of carbohydrate food quality across different food groups and different dietary patterns. The models were previously validated, and the current work demonstrates their applicability and utility across culturally and economically diverse eating patterns. However, the current work cannot show the effects of implementing CFQS models on specific health outcomes. Thus, future research will need to examine the health impacts of consuming higher scoring CFQS dietary patterns compared to lower scoring patterns. Furthermore, while the CFQS metrics emphasize nutrients of public health concern, the scoring system omits other key factors associated with health, such as bioavailability of nutrients, content of other nutrients, and contributions from bioactive phytonutrients (e.g., antioxidants, prebiotics, and probiotics). Future research will inform further development of the existing models to reflect these important components.