New Diabetes Nutrition Therapy Recommendations: What You Need to Know Free

The 2013 ADA nutrition statement was written at the request of the ADA Professional Practice Committee. In August 2012, the ADA convened a committee of nutrition experts in clinical practice and research, as well as other members of the diabetes health care team (a registered nurse/advanced practice nurse practitioner, a physician, and a pharmacist) to review the scientific literature and develop recommendations. The multidisciplinary committee followed the Institute of Medicine (IOM) Standards for Trustworthy Clinical Practice Guidelines.³  Based on the IOM standards, conflict of interest disclosures were obtained before confirmation of appointment of the co-chairs and the members of the committee/writing group. Development of the position statement was funded from ADA general revenues and not with any corporate or industry financial support.

The committee's work on the position statement began with an introductory conference call. The group reviewed an outline for the statement and assigned sections to specific members. Committee members were instructed to conduct thorough literature searches and create evidence tables for all of the topics included in the statement. Inclusion criteria for research studies providing evidence included:

• Adult subjects with a diagnosis of diabetes in an ambulatory or outpatient setting

• Published in English

• ≥ 10 participants

• Retention rates > 80%

Study design preference in ascending order included:

• Systematic review

• Randomized, controlled trial

• Clinical controlled study

• Prospective observational study

• Cross-sectional observational study

• Case-control study

Meal studies were excluded. Other exclusion criteria included research in individuals with:

• Prediabetes/metabolic syndrome

• Gestational diabetes/pregnancy

• Poor health status/diabetes complications or critical illness

The ADA's “Macronutrients, Food Groups, and Eating Patterns in the Management of Diabetes: A Systematic Review of the Literature,”⁴  published in 2012, served as a foundation for development of the new position statement. However, three crucial components of diabetes nutrition therapy were not addressed in this systematic review: effectiveness of diabetes nutrition therapy, energy balance, and healthful eating patterns in people with diabetes. For these three topics and others not included in the 2012 systematic review, PubMed data searches were conducted for articles published from January 2001 through April 2013. A table listing the supporting research for each recommendation is available online at http://professional.diabetes.org/nutrition.

A grading system developed by the ADA and modeled on existing methods was used to clarify and codify the evidence that forms the basis for the recommendations.¹  Depending on the quality of evidence, recommendations were assigned ratings of A, B, C, or expert opinion or expert consensus (E) based on no evidence from clinical trials (Table 1).¹  All of the 2013 recommendations and their corresponding evidence grades can be found in Table 2.

The recommendation development process continued with a face-to-face meeting of the entire committee, one subgroup writing meeting, numerous teleconferences, and multiple revisions via e-mail communications. The document received a comprehensive external review by leading diabetes nutrition clinicians and researchers in the United States. The statement was then reviewed and approved by the ADA Professional Practice Committee before being submitted to the ADA Executive Committee for final approval.

A notable difference between this statement and previous ones is the use of the term “nutrition therapy” instead of “medical nutrition therapy” (MNT). MNT is an evidence-based application of the nutrition care process provided by a registered dietitian/nutritionist (RD/N) and is the legal definition of nutrition counseling by an RD/N in the United States,⁵  whereas the IOM defines nutrition therapy as the treatment of a disease or condition through the modification of nutrient or whole-food intake. Therefore, nutrition therapy has a broader definition than MNT.⁶ 

Nutrition therapy research included in the 2013 position statement was conducted around the world by a wide variety of nutrition professionals, as well as physicians and registered advanced-practice nurses. HCPs administering nutrition interventions in studies conducted outside the United States did not provide MNT as it is legally defined.²  Thus, the term “nutrition therapy” was adopted in an effort to be more inclusive of the range of health professionals providing nutrition interventions and to recognize the broader definition of nutrition therapy. However, the unique academic preparation, training, skills, and expertise of RD/Ns make them the preferred members of the health care team to provide diabetes MNT.¹  Table 3 summarizes the Academy of Nutrition and Dietetics Evidence-Based Nutrition Practice Guidelines–recommended structure for the implementation of MNT for adults with diabetes.⁷ 

Review of the research conducted during the past decade reveals that diabetes nutrition therapy continues to be an effective management strategy for improving glycemic control and other metabolic parameters such as cholesterol and blood pressure levels. Effective nutrition therapy interventions can be provided either in one-on-one sessions with an RD/N or in group diabetes education classes.^7–15 

Research demonstrates that diabetes nutrition therapy can lower A1C levels by 0.3–1% in people with type 1 diabetes,^11,16–18  and people with type 2 diabetes can achieve A1C reductions of 0.5–2%.^9,10,19–32  Implementation of nutrition therapy in people newly diagnosed with type 2 diabetes who had an A1C of ~ 9% resulted in a decrease of ~ 2%,³³  whereas newly diagnosed people who had an A1C level of ~ 6.6% experienced a decrease of 0.4%.⁸  In both instances, reductions were significant and clinically meaningful.³⁴  Even in people with uncontrolled type 2 diabetes of ~ 9 years' duration, implementation of nutrition therapy significantly decreased A1C by ~ 0.5%, which was more cost-effective than adding a third medication.⁹ 

Because of the relationship between body weight (i.e., adiposity) and insulin resistance, weight loss has been recommended as a strategy for obese and overweight people with type 2 diabetes.¹  Prevention of weight gain is also important.²  Modest weight loss has been shown to improve glucose^35,36  and blood pressure,^35–40  increase HDL cholesterol,^{35–37,39–41}  and decrease triglyceride levels,^{35,36,39–42}  especially in those with newly diagnosed type 2 diabetes.

Effective nutrition therapy strategies for people with type 2 diabetes should emphasize reduced energy intake along with simplified meal plans such as healthful food choices or education on portion control. To achieve modest weight loss, intensive lifestyle interventions (physical activity, counseling about nutrition, and behavior change) with ongoing support are recommended. Unfortunately, because of the progressive nature of type 2 diabetes, physical activity and nutrition therapy may not be effective in maintaining desirable blood glucose control; over time, many individuals will need to add diabetes medications to their treatment plan. However, after diabetes medication is started, nutrition therapy continues to be a key part of type 2 diabetes self-management.

Adjusting mealtime insulin doses based on carbohydrate intake by using the carbohydrate-counting meal-planning approach has been shown to improve glycemia for people with type 1 diabetes^{16,17,43–45}  without increased risk of hypoglycemia.¹¹  For individuals using fixed daily insulin doses, consistent carbohydrate intake with respect to time and amount can result in improved glycemic control.^46,47 

Although HCPs frequently recommend an “ADA diet” as a diabetes nutrition intervention strategy, research continues to show that there is no single ideal diabetes eating plan. Research is also inconclusive regarding an ideal macronutrient distribution that is expected to benefit all individuals with diabetes.⁴  Therefore, the ADA does not endorse or advocate a specific diet or macronutrient distribution. The position statement writing group decided to use the term “eating plan” rather than “diet,” which historically has been negatively associated with restriction.

Because people eat food and not single nutrients such as carbohydrates, protein, and fat, the position statement includes a new section on eating patterns. Eating patterns can be defined as combinations of different foods or food groups. Many different types of eating patterns can be effective for achieving personal health goals for people with diabetes. Examples of eating patterns that have been studied in people with diabetes include Mediterranean-style, ^4,7,34,48,49  vegetarian or vegan,^26,50–54  low-carbohydrate,^46,55–61  low-fat,^{36,38–40,62–64}  and the American Heart Association's Dietary Approaches to Stop Hypertension.^65,66  Dietary patterns are influenced by perceptions of the healthfulness of certain foods, as well as by individuals' preferences, access to food and resources (e.g., budget/income), knowledge, health beliefs, religion, and culture.⁶⁷  Therefore, these factors should be considered when individualizing eating pattern recommendations.²  Patients' freedom to select from a variety of patterns given their individualized metabolic goals (i.e., for blood glucose, lipid, and blood pressure levels) and personal preferences should be supported by the health care team. When recommending particular eating patterns for an individual patient, the patient's total energy intake (and thus portion sizes) is an important consideration as well.² 

For the first time in an ADA nutrition position statement, the 2013 statement devotes a section to total fat intake. Research to date has provided inconclusive evidence to support a specific recommendation for total fat intake for people with diabetes.⁶⁸  However, the quality of the fat, rather than the quantity, appears to be a key component of a healthful eating plan.^48,69,70  The document advises that foods containing unsaturated fat (liquid oils) be substituted for those higher in saturated or trans fat and that leaner protein sources and meat alternatives should be preferred.⁶⁹ 

With regard to carbohydrates, the recommendations advise that people with diabetes should choose nutrient-dense, high-fiber foods, as opposed to processed foods with added fat, sugars, and sodium.^71,72 

Also new, the 2013 guidelines specifically call for the avoidance of sugar-sweetened beverages (SSBs; sweetened with any caloric sweetener including sucrose and high fructose corn syrup) to reduce the risk for weight gain and worsening of cardiometabolic risk profile.²  SSBs include soft drinks, fruit drinks, iced tea, energy drinks, and vitamin water containing sucrose, high-fructose corn syrup, or fruit juice concentrates. The evidence for this recommendation is abundant from studies in individuals without diabetes; there is little reason to suspect that the diabetic state would mitigate the adverse effects of SSBs.^73–77  The ADA nutrition recommendations also advise that the use of non-nutritive sweeteners has the potential to reduce overall calorie and carbohydrate intake if substituted for caloric sweeteners without compensation by intake of additional calories from other food sources.⁷⁸ 

In another change from the 2008 ADA nutrition recommendations, the limit for sodium is given as 2,300 mg/day—the same as for the general population.^79–81  Alternate individualized sodium targets are recommended for patients with both diabetes and hypertension.^65,82  Previously, the recommendation had been < 2,000 mg/day for all diabetes patients.

Regarding the use of vitamin and mineral supplements and herbal products, the literature review revealed a predominance of short-term, small, human studies (i.e., limited number of study participants) or animal studies. These studies are often poorly designed, making it difficult to prove efficacy based on their findings. Unfortunately, results from such studies are frequently extrapolated to clinical practice.⁸³  Based on its review of existing literature, the committee concluded that the benefit of pharmacological doses of supplements is unknown.^84,85  Similarly, evidence does not support recommending omega-3 supplements for people with diabetes as a way of preventing or treating cardiovascular disease.⁴ 

In an effort to help translate the position statement's recommendations into clinical practice, the writing group included for the first time in the 2013 statement a table titled “Summary of Priority Topics.” This table provides evidence-based nutrition management talking points that can be used by all members of the health care team. Topics include nutrition strategies for all people with diabetes and coordination of food with different classes of diabetes medications, including fixed-dose or basal-bolus insulin regimens, insulin secretagogues, incretin mimetics, and others.

The new position statement does not include sample meal plans because research conducted during the past decade has provided evidence that individualization is a key element of effective eating plans for people with diabetes.

A variety of eating patterns and meal-planning approaches can be effective for achieving individual metabolic goals for adults with diabetes. To eat well, it is best to eat nutrient-dense foods (i.e., fiber-rich foods that offer high levels of nutrients in appropriate portion sizes). Nutrition therapy goals should be developed collaboratively with individual diabetes patients. These goals should be based on assessment of individual patients' current eating patterns, personal and cultural preferences, access to healthful food choices, and willingness and ability to make changes in food and beverage choices, as well as their metabolic goals. Ideally, an eating plan should be developed early in the course of the disease in collaboration with an RD/N or through participation in a diabetes self-management group education class. Ongoing follow-up with a diabetes HCP is crucial for success; diabetes is a disease that is largely self-managed by patients who require professional support. Recommendations also may need to be adjusted over time based on changes in patients' life circumstances, preferences, and disease course.

The authors gratefully acknowledge all of the members of the position statement writing committee for their expertise, knowledge, and time devoted to completing this project: Stephanie A. Dunbar, MPH, RD, Cassandra L. Verdi, MPH, RD, Marjorie Cypress, PhD, C-ANP, CDE, Marion J. Franz, MS, RD, CDE, Elizabeth J. Mayer-Davis, PhD, RD, Joshua J. Neumiller, PharmD, CDE, CGP, FASCP, Robin Nwankwo, MPH, RD, CDE, Patti Urbanski, MEd, RD, LD, CDE, and William S. Yancy, Jr., MD, MHSC