Dietary Interventions for the Management of Diabetes

Educational Objectives

The goal of this program is to improve dietary management of hyperglycemia in prediabetes and diabetes mellitus (DM). After hearing and assimilating this program, the clinician will be better able to:

1. Encourage medical nutrition therapy for patients with DM.
2. Analyze features of various diet programs which may help in improving health of patients with prediabetes or DM.

Summary

Medical Nutrition Therapy (MNT)

Recommendations: the American Diabetes Association (ADA) consensus report emphasizes referring adults with prediabetes or diabetes mellitus (DM) types 1 and 2 to registered dietitian nutritionists (RDNs) for medical nutrition therapy (MNT); this referral should occur upon diagnosis and throughout the life of the patient when health status or treatment goals change; diabetes-related MNT is covered by Medicare and most commercial insurance policies; diabetes-related MNT should be implemented in a series of 3 to 6 visits with a RDN during the first 6 mo of diagnosis, with more visits added based on individualized patient needs; MNT should be part of annual follow-up for most patients

Outcome indicators: patients who receive MNT have reductions in HbA_1C similar to or greater than patients receiving medication without diet and nutrition therapy; strong evidence supports that people with type 1 and type 2 DM who receive MNT decrease HbA_1C by ≈2% in 3 to 6 mo; follow-up MNT is helpful in long-term maintenance of glycemic outcome indicators

Typical visit: the RDN assesses current dietary intake, eating pattern, and food preferences; the RDN then individualizes a meal plan, including balancing carbohydrates, proteins, and fats, based on metabolic goals and treatment plan; no ideal mix or limit exists regarding macronutrients and micronutrients, though balancing carbohydrates, proteins, and fat is important; on average, patients with DM consume macronutrient proportions similar to the general population; ≈45% of total daily calories come from carbohydrates, 36% to 40% from fat, and 16% to 18% from protein; carbohydrates in the form of dietary fiber are often overlooked without careful meal planning; people with DM and prediabetes are encouraged to eat at least the minimum daily amount of dietary fiber recommended by the United States Department of Agriculture (ie, ≈25 g for women, ≈38 g for men); 50 g/day of dietary fiber is required to achieve glycemic-lowering effects; the meal plan should include non-starchy vegetables, fresh fruits, pulses (eg, lentils, legumes, beans), whole grains, and dietary supplements (if necessary)

Dietary Patterns

Classic low-calorie diet: suggests a calorie deficit of 500 to 750 cal/day, typically equating to diets of 1200 to 1500 cal/day for women and 1500 to 1800 cal/day for men; in rare cases, an extremely low-calorie diet of 800 to 1000 cal/day has been proven to lower HbA_1C and promote weight loss in patients with prediabetes or DM when implemented by trained practitioners over 3 mo; high-quality protein is essential; use careful meal planning to ensure adequate vitamin, mineral, and fluid intake

Low-carbohydrate (LC) and very low-carbohydrate (VLC) diets: a LC diet generally derives 26% to 45% of total daily calories from carbohydrates, and a VLC diet derives <26% total daily calories from carbohydrates; glycemic improvements are significant; reducing total daily carbohydrates is a viable approach in select patients with type 2 DM in meeting glycemic goals and reducing medication burden

Low-fat (LF) and very low-fat (VLF) diets: derive <30% of total daily calories from fat and <10% from saturated fat; effective in individuals with prediabetes in reducing the risk for progression to type 2 DM and managing weight loss and blood pressure (BP) but does not appear to impart improved glycemic effects in patients with type 2 DM; the DIETFITS study (Gardner et al [2018]) noted no significant difference in weight loss and no significant diet-genome or diet-insulin interaction within 6 mo among patients following a LF or LC diet

Mediterranean-style diet (MSD): has the most robust evidence regarding benefits in glycemic control for patients with prediabetes and type 2 DM; compared with LF diet, the PREDIMED trial (Salas-Salvadó et al [2011]) found that the MSD (rich in olive oil, vegetables, nuts, seeds, beans, and fruits) reduced the incidence of DM disease progression with greater frequency, often in the absence of significant weight loss and physical activity

Vegetarian and vegan diets: data are not available to show the efficacy of weight loss, reduction of HbA_1C, and DM disease progression in patients with prediabetes, but it has been shown to lower low-density lipoprotein (LDL) and BP in some patients

Dietary approaches to stop hypertension (DASH) diet: proven effective for patients with prediabetes in preventing disease progression and improving weight management; limits sodium to 2.3 g/day while encouraging multiple servings of non-starchy vegetables, fruits, and whole grains, and limiting fats, oils, and added sugars; also encourages portion control

Paleolithic diet: consists of wild lean meats, fish, shellfish, vegetables, eggs, nuts, and berries; avoids grains, dairy, salt, refined fats, and sugars; studies have shown mixed results regarding efficacy in lowering HbA_1C, weight, and LDL

Intermittent fasting: focuses more on the time of eating than foods consumed; restricting oral intake for 10, 12, 16, 18, or 20 hr/day has shown promising results in some patients with type 2 DM, lowering HbA_1C and total body weight

Readings

Evert AB, Dennison M, Gardner CD, et al. Nutrition therapy for adults with diabetes or prediabetes: a consensus report. Diabetes Care. 2019;42(5):731-754. doi:10.2337/dci19-0014; Gardner CD, Trepanowski JF, Del Gobbo LC, et al. Effect of low-fat vs low-carbohydrate diet on 12-month weight loss in overweight adults and the association with genotype pattern or insulin secretion: the DIETFITS randomized clinical trial. JAMA. 2018;319(7):667–679. doi:10.1001/jama.2018.0245; Martín-Peláez S, Fito M, Castaner O. Mediterranean diet effects on type 2 diabetes prevention, disease progression, and related mechanisms. A review. Nutrients. 2020;12(8):2236. doi:10.3390/nu12082236; Salas-Salvadó J, Bulló M, Babio N, et al. Reduction in the incidence of type 2 diabetes with the Mediterranean diet: results of the PREDIMED-Reus nutrition intervention randomized trial [published correction appears in Diabetes Care. 2018 Oct;41(10):2259-2260]. Diabetes Care. 2011;34(1):14-19. doi:10.2337/dc10-1288.

Disclosures

For this program, members of the faculty and planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Rosenquist was recorded at the 2023 Updates in Diabetes Management, held November 3, 2023, in San Diego, CA, and presented by the Scripps Health. For information on future CME activities from this presenter, please visit https://www.scripps.org/conferenceservices. Audio Digest thanks the speakers and presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

IM711502

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.