Balancing multiple diets with comorbidities: Where to start?

In the United States, an estimated 42% of adults have been diagnosed with two or more chronic diseases. As this statistic continues to climb, healthcare systems are struggling to meet the increased demand for care. Multiple comorbidities can make care even more complex and highlight the need for a registered dietitian nutritionist (RDN) to be involved in the multidisciplinary treatment team.  

While individuals may be motivated to follow a particular diet, adherence without proper nutrition education and ongoing support can be frustrating and overwhelming. With this, the RDN must recognize the varying diet modifications, consolidate overlapping information, and effectively communicate recommendations.  

Health barriers and nutrition implications 

A poor diet is a significant barrier to improving health. It is associated with an increased risk for several comorbidities, including malnutrition, diabetes (DM), cardiovascular disease (CVD), stroke, obesity, chronic kidney disease (CKD), and cancer. Dietary intake rich in added sugar, sodium, and fat contributes to these chronic comorbidities.  

Additionally, eating excessive calories without consistent physical activity results in the storage of body fat and weight gain. Recognizing these concerns, the Dietary Guidelines for Americans 2020-2025 focused on limiting processed foods, maintaining healthy calorie goals, and incorporating nutrient-dense foods and beverages across different life stages.  

As many diet recommendations are pertinent for several comorbidities, nutrition education is crucial to consolidate and simplify recommendations. As part of an individualized assessment, the RDN can work with a patient to find the best approach for diet modification to support a healthy lifestyle and manage applicable chronic comorbidities.   

Patient care recommendations 

A thorough review of a patient’s comorbidities and an understanding of the goals most important to the patient are necessary building blocks for successfully combining multiple diet recommendations. When thinking about specific goals for conditions such as DM, CVD, hypertension, obesity, and CKD, consider that certain recommendations for each comorbidity overlap.  

Guidance from the RDN is critical in identifying the most beneficial diet modifications.  And focusing on recommendations that overlap, rather than separate interventions for each disease, can be helpful.  

Consider the following recommendations that may apply to multiple comorbidities: 

Sodium: A reduction in total dietary sodium is a well-known recommendation for many heart and kidney conditions. Total intake with these conditions should be limited to 2,300 milligrams or less daily. For comparison, the typical American diet contains an average of 3,400 milligrams or more daily.   

Since both a diet high in sodium and certain heart or kidney diseases are associated with an increased risk for the development of other comorbidities, decreasing dietary sodium is often recommended for overall health.   

Quick tips for lowering sodium intake include choosing fresh over processed foods, reading food labels, cooking meals at home more often than eating from restaurants, and replacing added salt with fresh herbs or spices.  

Fat: Limiting daily fat consumption, especially saturated and trans fats, can be beneficial for individuals with cancer, CVD, CKD, obesity, DM, and other comorbidities. The daily recommended intake of 20 to 35% of total calories from fat is encouraged as part of a general healthy diet.   

The lower end of the recommended range recognizes the essential role fat plays in a healthy diet. In contrast, the upper end of the range helps to discourage excess caloric intake that can lead to obesity and other associated health risks. Individualized goals for dietary fat should be emphasized.  

Consider focusing recommendations on selecting healthy polyunsaturated and monounsaturated fat sources with reduced intake of trans and saturated fats. Examples of poly- and monounsaturated fats include liquid non-tropical plant oils, fatty fish, certain nuts and seeds, avocado, and soy.  

Sugar: Added sugars have become more of a concern because of their negative impact on CVD, DM, cancer, and obesity. Recent statistics suggest that adults in the United States consume more than 17 teaspoons of added sugar per day, primarily from processed foods such as sugar-sweetened beverages, desserts, and snacks.  

Cutting back on these foods can support blood glucose control, weight management, and lower blood pressure. Additionally, increasing intake of foods containing natural sugars, such as fruit, vegetables, and low-fat dairy, should be highlighted as part of a nutrient-dense, balanced diet for those with DM, CKD, obesity, and CVD.  

Protein: For most chronic diseases, a reduction in dietary fat, specifically from certain protein sources, can be beneficial. Recommendations for cancer, obesity, DM, and CVD, among others, emphasize inclusion of lean protein choices.  

Selections can come from animal or plant-based sources, with an individualized approach suggested. Along with the type of protein source, discussion with the patient should touch on portion size, meal preparation, added seasonings, and the specific nutrients each protein source offers.  

Portion size: Clear communication regarding portion sizes is essential in nutrition therapy for multiple comorbidities. Often, too much of a particular nutrient comes from overeating. The Dietary Guidelines for Americans provide a foundation for a balanced diet, including a wide variety of foods in the correct portions. With support from the RDN, diet modification recommendations can be individualized to provide the right balance of food groups and/or nutrients with consideration for disease-specific diet interventions.  

For example, consider if a patient with CKD and DM requires diet education. Although potassium and carbohydrate limits may be necessary, a number of fruits can still be enjoyed in the correct portion size.  

Diet variety: Having several chronic conditions doesn’t mean an individual can’t include a variety of foods in their diet.  While some things may need to be consumed in moderation, balancing that with more nutrient-dense options can allow food preferences to be honored while maintaining nutrition goals.

A common concern among individuals trying to follow diet restrictions for multiple comorbidities is the lack of options and the thought that “there is nothing left to eat.” Education and ongoing support from an RDN can demonstrate how variety in the diet is possible and help lower frustrations. Consider the same example as above. It is critical that the RDN can effectively communicate that the entire food group (fruits) need not be avoided for management of DM and CKD. 

Conclusion

Managing multiple comorbidities has the potential to be frustrating or confusing for patients. RDNs can help alleviate these burdens by identifying overlapping nutrition information, simplifying recommendations, and helping identify appropriate patient goals.   

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References

Centers for Disease Control and Prevention. Chronic Disease Prevalence in the US: Sociodemographic and Geographic Variations by Zip Code Tabulation Area.  https://www.cdc.gov/pcd/issues/2024/23_0267.htm. Accessed February 3, 2025.  

World Health Organization. Fact Sheets: Healthy Diet. https://www.who.int/news-room/fact-sheets/detail/healthy-diet. Accessed February 19, 2025. 

Cavallo M, Morgana G, Dozzani I, et al. Unraveling barriers to a healthy lifestyle: Understanding barriers to diet and physical activity in patients with chronic non-communicable disease. Nutrients. 2023;15(15):3473. doi: 10.3390/nu15153473. 

American Heart Association. Effects of excess sodium infographic. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/sodium/effects-of-excess-sodium-infographic. Accessed February 23, 2025.  

American Heart Association. Fats. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/monounsaturated-fats. Accessed February 23, 2025. 

Centers for Disease Control and Prevention. Get the Facts: Added Sugars. https://www.cdc.gov/nutrition/php/data-research/added-sugars.html. Accessed February 23, 2025.  

Dietary Guidelines for Americans 2020-2025. Make Every Bite Count with Dietary Guidelines. https://www.dietaryguidelines.gov/sites/default/files/2021-03/Dietary_Guidelines_for_Americans-2020-2025.pdf#page=56. Accessed February 26, 2025.