Medical Nutrition Therapy for Diabetes Mellitus
Manual of Clinical Nutrition Management C- 6 Copyright © 2 013 Compass Group, Inc.
reduction of dietary protein to 0.8 g/kg of body weight per day (the Recommended Dietary Allowances) may
slow the progression of nephropathy (Grade II) (2,4). Along with testing for microalbuminuria, the analysis of a
spot urine sample to determine the albumin-to-creatinine ratio is strongly encouraged (1).
Small short-term studies suggest that diets with a protein content >20% of total energy reduce glucose and
insulin concentrations, reduce appetite, and increase satiety in patients with diabetes (31,32). The amount of
protein consumed at meals has minimal influence on the glycemic response, lipid levels, and hormones and
metabolites, and it has no long-term effect on insulin (Grade II) (4). As the percentage of protein increases and
the percentage of energy from carbohydrate decreases it is difficult to determine whether the higher protein
intakes or the lower carbohydrate intakes are responsible for significant effects on metabolic outcomes in
studies (Grade II) (4). The effects of high-protein diets on the long-term regulation of energy intake, satiety, and
weight as well as the ability of individuals to follow such diets long term have not been adequately studied;
therefore, high-protein diets are not recommended as a strategy to improve glycemic outcomes or promote
weight loss (Grade I) (1,2,4).
See the discussion on Energy Balance, Overweight, and Obesity in Diabetes in this section.
Fat Intake and Disorders of Lipid Metabolism
The distribution of energy from fat should be individualized based on the patient’s nutrition assessment,
cardiac risk assessment, disorders of lipid metabolism, and treatment goals (1-4,17,33,34).
Type 2 diabetes is associated with a twofold to fourfold excess risk of coronary heart disease (CHD) (Grade I)
(4,33). The most common disorders of lipid metabolism in patients with type 2 diabetes are elevated
triglycerides levels and decreased high-density lipoprotein cholesterol levels (33). The concentration of low-
density lipoprotein (LDL) cholesterol in patients with type 2 diabetes is similar to that in nondiabetic
individuals (33). The National Cholesterol Education Program (NCEP) Adult Treatment Panel III categorizes
persons with diabetes mellitus in the high-risk category with therapeutic goals to reduce LDL cholesterol
levels to less than 100 mg/dL through therapeutic lifestyle changes (diet and physical activity) and
cholesterol-lowering drug therapy (34). A subcategory of high risk, very high risk, consists of persons with
existing cardiovascular disease and diabetes as well as persons with cardiovascular disease and severe or
poorly controlled multiple risk factors (34). The very high–risk category has a therapeutic option to reduce
LDL cholesterol levels to less than 70 mg/dL (34). These lower LDL cholesterol goals, in combination with
initiating cholesterol-lowering drug therapy at lower thresholds, are based on evidence from five randomized
controlled trials that demonstrated a significantly reduced risk for cardiac events at these lower thresholds
(34). Pharmacologic therapy is integral in achieving these lower LDL thresholds and is recommended by the
NCEP to achieve a 30% to 40% reduction in baseline LDL cholesterol levels in all high-risk patients (34).
The recommended percentage of energy from fat depends on the patient’s lipid levels and treatment goals
for glucose, disorders of lipid metabolism, and weight. Because persons with diabetes mellitus are at high
risk of CHD and cardiovascular mortality (33,34), they should target the lowest LDL cholesterol goal (<100
mg/dL, or <70 mg/dL if categorized as very high risk) (2,33-35). Based on risk factor assessment, a person with
diabetes mellitus should follow the recommendations of the NCEP Adult Treatment Panel III, the American
Heart Association Dietary Guidelines 2000, and the American Diabetes Association Standards of Medical Care
2008 (1,35,36). The NCEP recommends that individuals with increased risk and/or disorders of lipid
metabolism limit their fat intake to less than 35% of total energy, with saturated and trans fat combined
targeting less than 7% of total energy (4), polyunsaturated fat restricted to less than 10% of total energy, and
monounsaturated fat targeting 10% to 15% of total energy (Grade I) (4,33).
Several studies have investigated the optimal mix of macronutrients to best support metabolic outcomes in
persons with diabetes and cardiovascular disease. Diets that are high in monounsaturated fat have not been
shown to improve fasting plasma glucose levels or A1C values (2). Low–saturated fat (<10% of energy), high-
carbohydrate diets increase postprandial levels of plasma glucose and insulin and increase plasma
triglycerides levels (37); in some studies, these diets decrease plasma high-density lipoprotein cholesterol
levels when compared with isoenergetic high–monounsaturated fat diets (2,37,38). When saturated-fat energy
is replaced with either energy from carbohydrate or monounsaturated fat, there is a reduction in plasma LDL
cholesterol levels (2). In other studies, when energy intake was reduced, the adverse effects of high-
carbohydrate diets were not observed (2). Individual variability in response to higher carbohydrate diets
(~55% of total energy) suggests that the plasma triglyceride response to dietary modifications should be
monitored carefully, particularly in the absence of weight loss (2). An individual’s metabolic profile and the
need for weight loss should determine the medical nutrition therapy recommendations and nutrition