The Healthy Eating Index (HEI) is a comprehensive measure of diet quality developed and maintained by the U.S. Department of Agriculture (USDA) and the National Cancer Institute (NCI). Its purpose is to assess how well a set of foods and beverages aligns with the recommendations of the Dietary Guidelines for Americans. The range of the Healthy Eating Index is consistently between 0 and 100, with 100 representing perfect alignment with the guidelines and 0 indicating no adherence.
How the Healthy Eating Index Score is Calculated
The total HEI score is the sum of scores for several dietary components, with points awarded based on the intake of specific food groups, nutrients, and overall dietary patterns. Each component has a scoring range, and the scores are weighted to contribute to the final 100-point total.
Components for Adequacy
These components reflect foods and nutrients that should be consumed in sufficient amounts for a healthy diet. For these components, a higher intake results in a higher score.
- Total Fruits: Points are awarded for the amount of fruit consumed.
- Whole Fruits: This category specifically measures the intake of whole fruits, not just juice.
- Total Vegetables: This component tracks overall vegetable consumption.
- Greens and Beans: Specific points are given for consuming dark green vegetables and legumes.
- Whole Grains: Intake of whole grains is measured.
- Dairy: Consumption of dairy products is assessed.
- Total Protein Foods: This includes meat, poultry, seafood, eggs, nuts, and seeds.
- Seafood and Plant Proteins: Points are awarded for choosing seafood and plant-based protein sources.
- Fatty Acids: The ratio of unsaturated fatty acids to saturated fatty acids is scored, favoring healthier fats.
Components for Moderation
These components track dietary elements that should be limited. For these, a lower intake results in a higher score.
- Refined Grains: Points are based on limiting intake of refined grains.
- Sodium: A lower daily sodium intake earns more points.
- Saturated Fats: Lower consumption of saturated fats is rewarded.
- Added Sugars: The amount of added sugars in the diet is limited.
What the Scores Mean
To better interpret the results, HEI scores are often categorized into quality ratings. These categories help translate a numerical score into an understandable evaluation of diet quality.
- Good Diet Quality (Score > 80): A score above 80 indicates a diet that is well-aligned with federal dietary guidelines. This is achieved by very few Americans.
- Needs Improvement (Score 51–80): Most Americans fall into this range. It signifies that while some aspects of the diet meet recommendations, there are areas, particularly with fruit, vegetable, and moderation components, that could be improved.
- Poor Diet Quality (Score < 51): This score suggests a diet that is not well-aligned with dietary guidelines and needs significant improvements across multiple components.
Comparison of Healthy Eating Index (HEI) Versions
The HEI has been updated several times to reflect revisions to the Dietary Guidelines for Americans. The core concept remains the same, but the specific components and scoring standards have evolved. For example, older versions included a component for variety, while newer ones have refined the components for protein and fat quality.
| Feature | HEI-1995 (10 Components) | HEI-2015/HEI-2020 (13 Components) |
|---|---|---|
| Core Concept | Measured conformity to the Food Guide Pyramid. | Measures conformity to the Dietary Guidelines for Americans. |
| Components | Focused on 5 food groups, 4 nutrients (total fat, saturated fat, cholesterol, sodium), and variety. | Includes more specific adequacy components like Whole Grains, Greens & Beans, and Seafood & Plant Proteins. |
| Moderation | Scored moderation for total fat, saturated fat, cholesterol, and sodium. | Explicitly scores moderation for refined grains, sodium, saturated fats, and added sugars. |
| Average U.S. Score | Mean score around 63.8-63.9. | Average score closer to 58 in recent years. |
The Healthy Eating Index and Health Outcomes
Numerous studies have utilized the HEI to examine the link between diet quality and various health outcomes. Research evaluating the HEI-2015, for instance, found that individuals with the highest diet quality (top 20% of HEI scores) had a significantly lower risk of dying from all causes, cancer, and heart disease compared to those with the lowest diet quality (bottom 20%). The HEI is also used to evaluate the impact of nutrition interventions and to monitor national dietary trends. A 2014 study found that the overall quality of the U.S. food supply improved slightly between 1970 and 2010 but still did not align well with national dietary guidance.
Conclusion
The range of the Healthy Eating Index (HEI) is a consistent 0 to 100, providing a clear and valuable metric for evaluating the quality of a diet. A higher score signifies closer alignment with the Dietary Guidelines for Americans, emphasizing adequate intake of healthy foods and moderation of unhealthy ones. Understanding where a diet falls within this range—whether in the 'good', 'needs improvement', or 'poor' category—is essential for public health officials and individuals alike to identify areas for improvement. While the average American score suggests a need for improvement, leveraging the HEI can guide better food choices that support long-term health and well-being. For a more detailed breakdown of the scoring standards for each component, readers can refer to resources from the USDA and NCI.
