Diabetes is a condition affecting the body's ability to produce or effectively use insulin, a hormone crucial for regulating blood sugar levels. Unmanaged diabetes can lead to serious health complications, including cardiovascular disease, nerve damage, kidney problems, eye damage, and skin issues. Effective diabetes management relies heavily on proper nutrition and regular exercise. A registered dietitian nutritionist (RDN), particularly one with specialized training as a certified diabetes care and education specialist, can provide invaluable support in navigating the complexities of diabetes and prediabetes.
The Role of a Dietitian in Diabetes Care
A dietitian specializing in diabetes plays a critical role in helping patients understand how various factors, such as food choices, exercise, illness, stress, and weight loss, influence blood sugar levels. They can help individuals with diabetes improve blood glucose control. This includes learning how different foods affect blood sugar and how to build balanced meals that contain fiber, protein, and healthy fat to prevent blood sugar spikes. Registered dietitians have specialized nutrition expertise to help people with all forms of diabetes improve their overall health and reduce the risk of related health conditions.
Medical Nutrition Therapy (MNT): A Personalized Approach
Medical nutrition therapy (MNT) is a cornerstone of diabetes management. It involves a customized plan that utilizes food and nutrition to manage or treat health conditions. After assessing your medical history, current health problems, and eating habits, a dietitian helps you set individualized nutrition-related goals. Reducing the risk of long-term complications and improving health status is always at the heart of MNT. Once these things have been assessed and goals have been laid out, a dietitian will work with you to create a plan to help you reach your goals. During MNT, the dietitian assesses the patient's medical history, current health status, and eating habits to establish personalized nutrition-related goals. The primary focus of MNT is to reduce the risk of long-term complications and improve overall health.
Essential components of MNT are assessment, nutrition diagnosis, interventions (e.g., education and counseling), and monitoring with ongoing follow-up to support long-term lifestyle changes, evaluate outcomes, and modify interventions as needed.
Key Objectives of MNT
- Improve A1C, blood pressure, and cholesterol levels (goals differ for individuals based on age, duration of diabetes, health history, and other present health conditions.
The unique academic preparation, training, skills, and expertise make the RDN the preferred member of the health care team to provide diabetes MNT and leadership in interprofessional team-based nutrition and diabetes care. Although certification (such as Certified Diabetes Educator, Board Certified-Advanced Diabetes Management) is not required, ideally the RDN will have comprehensive knowledge and experience in diabetes care and prevention.
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When to Seek MNT
Refer adults living with type 1 or type 2 diabetes to individualized, diabetes-focused MNT at diagnosis and as needed throughout the life span and during times of changing health status to achieve treatment goals.
Health care professionals can use the education algorithm suggested by ADA, the American Association of Diabetes Educators, and the Academy of Nutrition and Dietetics that defines and describes the four critical times to assess, provide, and adjust care. The algorithm is intended for use by the RDN and the interprofessional team for determining how and when to deliver diabetes education and nutrition services.
The Importance of Diabetes Self-Management Education and Support (DSMES)
In addition to diabetes MNT, DSMES is important for people with diabetes to improve cardiometabolic and microvascular outcomes in a disease that is largely self-managed.
The Benefits of MNT
Reported hemoglobin A1c (A1C) reductions from MNT can be similar to or greater than what would be expected with treatment using currently available medication for type 2 diabetes. Strong evidence supports the effectiveness of MNT interventions provided by RDNs for improving A1C, with absolute decreases up to 2.0% (in type 2 diabetes) and up to 1.9% (in type 1 diabetes) at 3-6 months. Cost-effectiveness of lifestyle interventions and MNT for the prevention and management of diabetes has been documented in multiple studies. The National Academy of Medicine recommends individualized MNT, provided by an RDN upon physician referral, as part of the multidisciplinary approach to diabetes care.
Nutrition Recommendations for Diabetes Management
While a "one-size-fits-all" eating plan is not appropriate for everyone with diabetes or prediabetes, some general nutritional guidelines can be beneficial. These recommendations consider individual needs, preferences, cultural backgrounds, co-occurring health conditions, and socioeconomic factors.
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Macronutrient Balance
Although numerous studies have attempted to identify the optimal mix of macronutrients for the eating plans of people with diabetes, a systematic review found that there is no ideal mix that applies broadly and that macronutrient proportions should be individualized.
It has been observed that people with diabetes, on average, eat about the same proportions of macronutrients as the general public: ∼45% of their calories from carbohydrate (see Table 3), ∼36-40% of calories from fat, and the remainder (∼16-18%) from protein. Regardless of the macronutrient mix, total energy intake should be appropriate to attain weight management goals.
Carbohydrates: Quality and Quantity
Carbohydrate is a readily used source of energy and the primary dietary influence on postprandial blood glucose. Foods containing carbohydrate-with various proportions of sugars, starches, and fiber-have a wide range of effects on the glycemic response. Some result in an extended rise and slow fall of blood glucose concentrations, while others result in a rapid rise followed by a rapid fall. The amount of carbohydrate intake required for optimal health in humans is unknown.
Since carbohydrates are the main source of glucose, learning how to portion carbohydrates is a key part of diabetes management. A dietitian specializing in diabetes can teach you easy tools to help you count carbohydrates and track how many you consume.
Fiber: An Important Component
The regular intake of sufficient dietary fiber is associated with lower all-cause mortality in people with diabetes. Therefore, people with diabetes should consume at least the amount of fiber recommended by the DGA 2015-2020 (minimum of 14 g of fiber per 1,000 kcal) with at least half of grain consumption being whole intact grains. A few studies have shown modest A1C reduction (−0.2% to −0.3%) with intake in excess of 50 g of fiber per day. However, such very high intake of fiber may cause flatulence, bloating, and diarrhea. Dietary fiber includes all parts of plant foods that your body can't digest or absorb. Fiber moderates how your body digests food and helps control blood sugar levels.
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Glycemic Index and Glycemic Load
The use of the glycemic index (GI) and glycemic load (GL) to rank carbohydrate foods according to their effects on glycemia continues to be of interest for people with diabetes and those at risk for diabetes. As defined by Brand-Miller et al., “the GI provides a good summary of postprandial glycemia. It predicts the peak (or near peak) response, the maximum glucose fluctuation, and other attributes of the response curve.” Two systematic reviews of the literature regarding GI and GL in individuals with diabetes and at risk for diabetes reported no significant impact on A1C and mixed results on fasting glucose. Some people who live with diabetes use the glycemic index to select foods, especially carbohydrates. This method ranks carbohydrate-containing foods based on their effect on blood sugar levels.
Protein: An Essential Nutrient
There is limited research in people with diabetes or prediabetes without kidney disease on the impact of various amounts of protein consumed. Some comparisons of protein amounts have not demonstrated differences in diabetes-related outcomes. A 12-week study comparing 30% vs. 15% energy from protein noted improvements in weight, fasting glucose, and insulin requirements in the group that consumed 30% energy from protein. A meta-analysis from 2013 of studies ranging from 4-24 weeks in duration reported that high-protein eating plans (25-32% of total energy vs.
Fats: Quality over Quantity
The National Academy of Medicine has defined an acceptable macronutrient distribution for total fat for all adults to be 20-35% of total calorie intake. Eating patterns that replace certain carbohydrate foods with those higher in total fat, however, have demonstrated greater improvements in glycemia and certain CVD risk factors (serum HDL cholesterol [HDL-C] and triglycerides) compared with lower fat diets. The types or quality of fats in the eating plans may influence CVD outcomes beyond the total amount of fat. Foods containing synthetic sources of trans fats should be minimized to the greatest extent possible. Foods containing monounsaturated and polyunsaturated fats can help lower your cholesterol levels.
Cholesterol: A Complex Relationship
The body makes enough cholesterol for physiological and structural functions such that people do not need to obtain cholesterol through foods. Although the DGA concluded that available evidence does not support the recommendation to limit dietary cholesterol for the general population, exact recommendations for dietary cholesterol for other populations, such as people with diabetes, are not as clear. Whereas cholesterol intake has correlated with serum cholesterol levels, it has not correlated well with CVD events. Cholesterol sources include high-fat dairy products and high-fat animal proteins, egg yolks, liver, and other organ meats.
Omega-3 Fatty Acids: Potential Benefits
Large epidemiologic studies have found that consumption of polyunsaturated fat or biomarkers of polyunsaturated fatty acids are associated with lower risk of type 2 diabetes. Supplementation with omega-3 fatty acids in prediabetes has demonstrated some efficacy in surrogate outcomes beyond serum triglyceride levels. In a single-blinded RCT design in Asia, 107 subjects with newly diagnosed impaired glucose metabolism and coronary heart disease (CHD) supplemented with 1,800 mg/day of eicosapentaenoic acid (EPA) experienced improved postprandial triglycerides, glycemia, insulin secretion ability, and endothelial function over a 6-month period. Eat heart-healthy fish at least twice a week. Fish such as salmon, mackerel, tuna and sardines are rich in omega-3 fatty acids. These omega-3s may prevent heart disease. If you are pregnant, are planning to get pregnant or are breastfeeding, do not eat fish that's typically high in mercury.
Sodium: Moderation is Key
Aim for no more than 2,300 mg of sodium a day.
Popular Eating Patterns for Diabetes Management
An eating pattern represents the totality of all foods and beverages consumed. The most robust research available related to eating patterns for prediabetes or type 2 diabetes prevention are Mediterranean-style, low-fat, or low-carbohydrate eating plans.
Mediterranean-Style Eating Pattern
The intervention in the PREvención con DIeta MEDiterránea (PREDIMED) study, comparing a Mediterranean-style eating pattern supplemented either with extra-virgin olive oil or with nuts versus a control diet, reduced incidence of type 2 diabetes among people without diabetes at high cardiovascular risk at baseline. The PREDIMED trial, a large RCT, compared a Mediterranean-style to a low-fat eating pattern for prevention of type 2 diabetes onset, with the Mediterranean-style eating pattern resulting in a 30% lower relative risk. Emphasizes vegetables, fruits, and low-fat dairy products; includes whole intact grains, poultry, fish, and nuts; reduced in saturated fat, red meat, sweets, and sugar-containing beverages.
Low-Fat Eating Pattern
Several large type 2 diabetes prevention RCTs used low-fat eating plans to achieve weight loss and improve glucose tolerance, and some demonstrated decreased incidence of diabetes.
Low-Carbohydrate Eating Pattern
Emphasizes vegetables low in carbohydrate (such as salad greens, broccoli, cauliflower, cucumber, cabbage, and others); fat from animal foods, oils, butter, and avocado; and protein in the form of meat, poultry, fish, shellfish, eggs, cheese, nuts, and seeds. Some plans include fruit (e.g., berries) and a greater array of nonstarchy vegetables. Avoids starchy and sugary foods such as pasta, rice, potatoes, bread, and sweets. There is no consistent definition of “low” carbohydrate.
Very Low-Carbohydrate Eating Pattern
Similar to low-carbohydrate pattern but further limits carbohydrate-containing foods, and meals typically derive more than half of calories from fat. Often has a goal of 20-50 g of nonfiber carbohydrate per day to induce nutritional ketosis.
Paleo Eating Pattern
Emphasizes foods theoretically eaten regularly during early human evolution, such as lean meat, fish, shellfish, vegetables, eggs, nuts, and berries.
Dietary Approaches to Stop Hypertension (DASH) Eating Plan
Emphasizes a variety of vegetables from all of the subgroups; fruits, especially whole fruits; grains, at least half of which are whole intact grains; lower-fat dairy; a variety of protein foods; and oils.
Traditional American Cuisine
Emphasizes vegetables, fruits, starches (e.g., breads/crackers, pasta, whole intact grains, starchy vegetables), lean protein sources (including beans), and low-fat dairy products.
Diabetes and Prediabetes
People who are at risk of developing type 2 diabetes may be diagnosed with pre-diabetes. Elevated blood sugar is a sign that your body is starting to develop insulin resistance. Eating balanced meals, reducing intake of sweets and refined carbohydrates, increasing physical activity, and losing weight can reverse this condition and prevent it from becoming full-blown type 2 diabetes.
Substantial evidence indicates that individuals with prediabetes should be referred to an intensive behavioral lifestyle intervention program modeled on the DPP and/or to individualized MNT typically provided by an RDN with the goals of improving eating habits, increasing moderate-intensity physical activity to at least 150 min per week, and achieving and maintaining 7-10% loss of initial body weight if needed. To make diabetes prevention programs more accessible, digital health tools are an area of increasing interest in the public and private sectors.
Gestational Diabetes
Hormonal imbalances during pregnancy can make your body less responsive to insulin, resulting in higher-than-normal blood glucose levels. This is known as gestational diabetes. It usually occurs in the second half of pregnancy and resolves after the baby is born. Like type 2 diabetes, some pregnant women can keep blood glucose levels stable by improving healthy eating habits and getting more physical activity.
Healthy Eating: A Delicious Approach
Healthy eating for prediabetes and diabetes not only helps to manage your blood glucose (blood sugar), but it also helps you have a better relationship with food. Intentional food choices like eating more non-starchy veggies, opting for lean meats or plant-based proteins, choosing quality carbohydrates, and low-fat versions of cheeses and dressings, will all help you meet your health goals-and they’ll taste great too! It is not about one food, or one meal, it’s about healthy eating over time.
Meal Planning Strategies
You may use a few different approaches to create a healthy diet to help you keep your blood sugar level within a typical range. The American Diabetes Association offers a simple method of meal planning. It focuses on eating more vegetables. To help control your blood sugar, you may need to learn to figure out the amount of carbohydrates you are eating with the help of a dietitian. You can then adjust the dose of insulin accordingly. A dietitian can teach you how to measure food portions and become an educated reader of food labels. A dietitian may recommend you choose specific foods to help plan meals and snacks. One serving in a category is called a choice. A food choice has about the same amount of carbohydrates, protein, fat and calories - and the same effect on your blood sugar - as a serving of every other food in that same category.
When planning meals, take into account your size and activity level.