Diabetes in Adults: Medical Nutrition Therapy

The registered dietitian nutritionist (RDN), in collaboration with other members of the health care team, should ensure that all overweight or obese adults at risk are screened for type 2 diabetes. Testing to assess risk for future diabetes in asymptomatic people should be considered in adults of any age who are overweight or obese (BMI ≥25 kg/m2 or ≥23 kg/m2 in Asian Americans) and who have one or more additional risk factors for diabetes. (Fair, Imperative)

The RDN, in collaboration with other members of the health care team, should ensure that all adults with type 1 diabetes and type 2 diabetes are referred for MNT. Individuals who have diabetes should receive individualized MNT to achieve treatment goals, preferably provided by a RDN familiar with the components of diabetes MNT. (Strong, Imperative)

The RDN should implement three to six MNT encounters during the first six months and determine if additional MNT encounters are needed. In studies reporting on the implementation of an initial series of RDN encounters (3–11; total of 2–16 hours), MNT significantly lowered HbA1c by 0.3%–2.0% in adults with type 2 diabetes and by 1.0%–1.9% in adults with type 1 diabetes during the first six months, as well as optimization of medication therapy and improved quality of life. (Strong, Imperative)

The RDN should implement a minimum of one annual MNT follow-up encounter. Studies longer than six months report that continued MNT encounters resulted in maintenance and continued reductions of A1C for ≤2 years in adults with type 2 diabetes, and for ≤6.5 years in adults with type 1 diabetes. (Strong, Imperative)

• The RDN should assess the following in adults with type 1 diabetes and type 2 diabetes, to formulate the nutrition care plan:

  Biochemical data, medical tests and medication usage:

  • Type of diabetes
  • Glycemic control (target glucose and A1C levels are noted in the annual American Diabetes Association Standards of Medical Care in Diabetes)
  • Lipid profiles
  • Blood pressure
  • Stage of chronic kidney disease
  • Use of glucose-and lipid-lowering medications, anti-hypertensive medications, prescription and other over-the-counter medications, herbal supplements and complementary or alternative medications.

  Nutrition-focused physical findings:

  • Height, weight, BMI and waist circumference
  • Injection sites
  • Relative importance of weight management.

  Client history:

  • General health and demographic information
  • Social history
  • Cultural preferences
  • Health literacy and numeracy
  • Education and occupation
  • Knowledge, beliefs, attitudes, motivation, readiness to change, self-efficacy and willingness and ability to make behavioral changes
  • Physical activity
  • Patient or family nutrition-related medical and health history
  • Other medical or surgical treatments
  • Previous nutrition care services and MNT recommendations.

  Food and nutrition-related history:

  • Food, beverage and nutrient intake including energy intake, serving sizes, meal-snack patterns, carbohydrate, fiber, types and amounts of fat, protein, micronutrient intake and alcohol intake
  • Experience with food, previous and current food and nutrition history, eating environment, access to healthy foods and eating out.

  Assessment of the patient’s psychological and social situation should be included as an ongoing part of the medical management of diabetes, which may include, but is not limited to, attitudes about the illness, expectations for medical management and outcomes, affect and mood, general and diabetes-related quality of life, resources (financial, social and emotional), and psychiatric history, as well as addressing common co-morbid conditions that may complicate diabetes management.

(Fair, Imperative)

The RDN should individualize the nutrition prescription and implement evidence-based guidelines in collaboration with the adult with diabetes. A variety of eating patterns (combinations of different foods or food groups) are acceptable for the management of diabetes. Personal preferences (e.g., tradition, culture, religion, health beliefs and goals, economics) and metabolic goals should be considered when recommending one eating pattern over another. Treatment decisions should be founded on evidence-based guidelines tailored to individual patient preferences, prognoses and co-morbidities. (Fair, Imperative)

For appropriate-weight adults with diabetes, the RDN should encourage consumption of a healthful eating plan, with a goal of weight maintenance and prevention of weight gain. A variety of eating patterns (combinations of different foods or food groups) are acceptable for the management of diabetes. (Consensus, Conditional)

For overweight or obese adults with diabetes, the RDN should encourage a reduced energy, healthful eating plan, with a goal of weight loss, weight loss maintenance and prevention of weight gain. Studies based on reduced energy interventions reported significant reductions in HbA1c of 0.3%–2.0% in adults with type 2 diabetes and of 1.0%–1.9% in adults with type 1 diabetes, as well as optimization of medication therapy and improved quality of life. (Strong, Conditional)

The RDN, in collaboration with the adult with diabetes, should individualize the macronutrient composition of the healthful eating plan within the appropriate energy intake. Limited research regarding differing amounts of carbohydrate (39%–57% of energy) and fat (27%–40% of energy), reported no significant effects on A1C or insulin levels in adults with diabetes, independent of weight loss. Limited research reports mixed results regarding the effects of the amount of protein (ranging from 0.8–2.0 g/kg/day) on fasting glucose levels and A1C. (Fair, Imperative)

The RDN should educate adults with type 1 diabetes or type 2 diabetes on multiple daily injections (MDI) of insulin or insulin pump therapy on carbohydrate counting using insulin-to-carbohydrate ratios based on his or her abilities, preferences and management goals. Research reports that carbohydrate counting using insulin-to-carbohydrate ratios resulted in significant decreases in A1C of 0.4%–1.6% and significant increases in quality of life, as well as continued maintenance of these improvements for ≤44 months. The majority of research reported no significant change in weight as a result of this carbohydrate management strategy. (Strong, Conditional)

The RDN should educate adults with type 1 diabetes or type 2 diabetes on fixed insulin doses or adults with type 2 diabetes on insulin secretagogues, based on his or her abilities, preferences and management goals, on carbohydrate consistency (timing and amount) using one of the following carbohydrate management strategies:

• Carbohydrate counting alone
• Plate method, portion control and simplified meal plan
• Food lists (such as Choose Your Foods. Food Lists for Diabetes) and carbohydrate choices.

For individuals using fixed insulin doses (or insulin secretagogues), consistent carbohydrate intake with respect to time and amount can result in improved glycemic control and reduce risk for hypoglycemia. Monitoring carbohydrate intake, whether by carbohydrate counting or experience-based estimation remains a key strategy in achieving glycemic control. A simple diabetes healthful eating plan approach such as portion control or healthful food choices may be better suited to individuals with type 2 diabetes who have low health literacy or numeracy concerns.

(Fair, Conditional)

The RDN should educate adults with type 2 diabetes on MNT alone or on diabetes medications other than insulin secretagogues, based on his or her abilities, preferences and management goals, on one of the following carbohydrate management strategies:

• Carbohydrate counting alone
• Plate method, portion control and simplified meal plan
• Food lists (such as Choose Your Foods. Food Lists for Diabetes) and carbohydrate choices.

Monitoring carbohydrate intake, whether by carbohydrate counting or experience-based estimation remains a key strategy in achieving glycemic control. A simple diabetes healthful eating plan approach such as portion control or healthful food choices may be better suited to individuals with type 2 diabetes who have low health literacy or numeracy concerns.

(Fair, Conditional)

The RDN should encourage adults with diabetes to consume dietary fiber from foods such as fruits, vegetables, whole grains and legumes, at the levels recommended by the Dietary Reference Intakes (21–25 g per day for adult women and 30–38 g per day for adult men, depending on age) or U.S. Department of Agriculture (14 g fiber/1,000 kcal) due to the overall health benefits of dietary fiber. Limited research regarding differing amounts of fiber intake from foods, independent of weight loss, reported mixed results on A1C and no significant effects on exogenous insulin levels. (Fair, Imperative)

If glycemic index or glycemic load is proposed as a glycemia-lowering strategy, the RDN can advise adults with diabetes that lowering glycemic index or glycemic load may or may not have a significant effect on glycemic control. Studies ≥12 weeks report no significant impact of glycemic index or glycemic load, independent of weight loss, on A1C. However, mixed results were reported regarding fasting glucose levels and endogenous insulin levels. (Fair, Conditional)

The RDN should educate adults with diabetes that intake of nutritive sweeteners, when substituted isocalorically for other carbohydrates, will not have a significant effect on A1C or insulin levels. Research reported no significant impact from consuming nutritive sweeteners (such as isomaltulose and sucrose), independent of weight loss, on A1C or insulin levels. However, mixed results were reported regarding fasting blood glucose. (Fair, Imperative)

The RDN should advise adults with diabetes against excessive intake of nutritive sweeteners to avoid displacing nutrient-dense foods and to avoid excessive caloric and carbohydrate intake. Higher intake of added sugars may contribute to higher energy intake. (Fair, Imperative)

The RDN should educate adults with diabetes that intake of FDA-approved non-nutritive sweeteners (such as aspartame, sucralose and stevia) within the recommended daily intake levels established by FDA will not have a significant effect on glycemic control. Research reports no significant impact of consuming FDA-approved non-nutritive sweeteners [such as aspartame, stevia (steviol glycosides) and sucralose], independent of weight loss, on A1C, fasting glucose levels or insulin levels. (Weak, Imperative)

The RDN should educate adults with diabetes that substituting foods and beverages containing FDA-approved non-nutritive sweeteners within the recommended daily intake levels established by FDA can reduce overall calorie and carbohydrate intake. However, other sources of calories and carbohydrates in these foods and beverages need to be considered. 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. (Fair, Imperative)

The RDN should educate adults with diabetes that adding protein to meals and snacks does not prevent or assist in the treatment of hypoglycemia. Ingested protein appears to increase insulin response without increasing plasma glucose concentrations. Therefore, carbohydrate sources high in protein should NOT be used to treat or prevent hypoglycemia. (Fair, Imperative)

For adults with diabetes and DKD, the RDN does not need to prescribe a protein restriction. While research reports mixed results regarding the effects of the amount of protein on fasting glucose levels and A1C, independent of weight loss, in adults with type 1 diabetes and type 2 diabetes and DKD, there was no significant impact of protein intake (ranging from 0.7–2.0g/kg/day) on GFR. (Strong, Conditional)

The RDN should advise adults with type 2 diabetes and DKD that the type of protein (vegetable-based vs. animal-based) will not have a significant effect on GFR. However, there may be an effect on fasting glucose levels and proteinuria. While one study reports a positive impact of soy protein compared to animal protein on proteinuria and fasting glucose levels, independent of weight loss, in adults with type 2 diabetes and DKD, there was no significant impact of soy protein consumption on GFR. (Weak, Conditional)

The RDN should encourage consumption of a cardioprotective dietary pattern, within the recommended energy intake. While research reports no significant effect of differing amounts of saturated fat, unsaturated fat and omega-3 fatty acids on glycemia or insulin levels, independent of weight loss, modifications to decrease saturated fat intake and increase unsaturated fat intake reduced total cholesterol and LDL-cholesterol in three of six studies. (Strong, Imperative)

The RDN should encourage an individualized reduction in sodium intake. The recommendation for the general population to reduce sodium to <2,300 mg per day is also appropriate for adults with diabetes. For adults with both diabetes and hypertension, further reduction in sodium intake should be individualized. (Fair, Imperative)

If vitamin, mineral and herbal supplementation is proposed as a diabetes management strategy, the RDN can advise adults with diabetes that there is no clear evidence of benefit from supplementation in people who do not have underlying deficiencies. Routine supplementation with antioxidants (such as vitamins E and C and carotene) and other micronutrients (such as chromium, magnesium and vitamin D) and herbal supplements (such as cinnamon) are not advised due to lack of evidence of efficacy and concern related to long-term safety. (Fair, Conditional)

The RDN should advise and educate adults with diabetes that if they choose to drink alcohol, they should do so in moderation (one drink per day or less for adult women and two drinks per day or less for adult men). Alcohol consumption may place adults with diabetes at increased risk for delayed hypoglycemia, especially if using insulin or insulin secretagogues. (Weak, Conditional)

The RDN should encourage an individualized physical activity plan for adults with diabetes, unless medically contraindicated, to gradually achieve the following:

• Accumulating 150 minutes or more of physical activity per week
• Moderate-intensity aerobic exercise (50–70% of maximum heart rate) spread over at least three days per week with no more than two consecutive days without exercise
• Resistance training at least twice per week
• Reduce sedentary time by breaking up extended amounts of time
  (>90 minutes) spent sitting.

Adults with diabetes should be advised to perform ≥150 minutes per week of moderate-intensity aerobic physical activity (50%–70% of maximum heart rate), spread over at least three days per week with no more than two consecutive days without exercise.

(Strong, Imperative)

The RDN should educate adults with diabetes taking insulin or insulin secretagogues that physical activity may cause hypoglycemia if medication doses or carbohydrate consumption is not altered. Individual glycemic response patterns can differ markedly with exercise; therefore, persons with diabetes taking insulin or insulin secretagogues must use glucose monitoring and recognition of glucose patterns to make decisions to exercise safely. (Consensus, Conditional)

The RDN should ensure that adults with type 1 diabetes and type 2 diabetes are educated about glucose monitoring and using data to adjust therapy. When prescribed as part of a broader educational context, results may help guide treatment decisions and self-management. (Fair, Imperative)

The RDN should implement MNT and coordinate care with an interdisciplinary health care team, the adult with diabetes and important others (e.g., family, friends and colleagues). Care systems should support team-based care and community involvement to meet patient needs, ensuring productive interactions between a prepared, proactive practice team and an informed, activated patient. (Strong, Imperative)

• The RDN should monitor and evaluate the following in adults with type 1 diabetes and type 2 diabetes, to determine the effectiveness of MNT:

  Biochemical data, medical tests and medication usage:

  • Glycemic control (target glucose and A1C levels are noted in the annual American Diabetes Association Standards of Medical Care in Diabetes)
  • Results of glucose monitoring
  • Lipid profiles
  • Blood pressure
  • Stage of chronic kidney disease
  • Use of glucose-and lipid-lowering medications, anti-hypertensive medications, prescription and other over-the-counter medications, herbal supplements and complementary or alternative medications.

  Nutrition-focused physical findings:

  • Height, weight, BMI and waist circumference
  • Injection sites
  • Relative importance of weight management.

  Client history:

  • Knowledge, beliefs, attitudes, motivation, readiness to change, self-efficacy and willingness and ability to make behavioral changes
  • Physical activity
  • Other medical or surgical treatments.

  Food and nutrition-related history:

  • Food, beverage and nutrient intake including energy intake, serving sizes, meal-snack patterns, carbohydrate, fiber, types and amounts of fat, protein, micronutrient intake and alcohol intake
  • Eating environment, access to healthy foods and eating out.

  Monitoring and evaluation of the patient’s psychological and social situation should be included as an ongoing part of the medical management of diabetes, which may include but is not limited to attitudes about the illness, expectations for medical management and outcomes, affect or mood, general and diabetes-related quality of life, resources (financial, social and emotional) and psychiatric history, as well as addressing common co-morbid conditions that may complicate diabetes management.

(Fair, Imperative)