Authors
- Lydia Bazzano, MD, PhD
- Mark Cucuzzella, MD, FAAFP
- Eric Westman, MD, MHS
- William Yancy, MD, MHS
Overview
Prevalence of Target Diseases
- The prevalence of prediabetes and type 2 diabetes has increased dramatically over several decades in parallel with the increasing prevalence of obesity.
- Most recent estimates in 2015 state that 34% of Americans have prediabetes (hemoglobin A1c 5.7-6.4%) and 9.4% have type 2 diabetes (hemoglobin A1c ≥6.5% or on diabetes medication).
- Obesity, prediabetes and type 2 diabetes are all risk factors for cardiovascular disease (CVD), and their increasing prevalence is now leading to an increase in the prevalence of CVD.
Key Points and Scope
- Low-carbohydrate eating patterns are recognized in scientific literature and expert treatment guidelines as effective nutritional therapies for obesity, prediabetes and type 2 diabetes.
- Because low- and very-low-carbohydrate eating patterns are effective treatments for these risk factors, plus risk factors such as hypertriglyceridemia and low high density lipoprotein (HDL) cholesterol (metabolic syndrome), their use has real potential for reducing CVD.
- Low- and very-low-carbohydrate eating patterns can have potent lowering effects on blood glucose and blood pressure, which can lead to hypoglycemia or hypotension in people taking diabetes or blood pressure medications, respectively. Therefore, medication reduction, or deprescribing, is often required at the onset of dietary change, as is ongoing monitoring and medication management.
- Numerous additional nuances to the use of these nutritional approaches have led to the production of this pocket guide, which is intended to assist practitioners in the safe and effective use of low-carbohydrate nutrition.
- This pocket guide will define and describe low-carbohydrate nutritional approaches, identify appropriate target patient populations, and summarize recommended practices for the use of such eating patterns in adults, particularly adults with obesity, prediabetes or type 2 diabetes.
- This pocket guide is not intended for treatment of children or people with type 1 diabetes, who may require adjustments to the approaches described.
Assessment
Vital Sign Essentials
- Weight
- Height
- Waist circumference
- Start at the top of the hip bone, then bring the tape measure all the way around the body, level with the umbilicus. The patient can hold the beginning of the tape measure at the umbilicus and rotate 360⁰ in front of you to accomplish this.
- Make the tape snug but not tight and record the measurement right after exhalation.
Note: if waist circumference multiplied by 2 is greater than the patient's height, then risk is higher for metabolic syndrome. Use the same unit of measurement for both (e.g., inches).
- Blood pressure and heart rate
- Patient should be seated, relaxed, and rested for 5 minutes prior to measurement. Use appropriate sized cuff, as a cuff that is too small falsely elevates the reading.
Note: Many patients with diabetes have stiff arteries due to arteriosclerosis, which can cause a falsely elevated blood pressure reading.
- Patient should be seated, relaxed, and rested for 5 minutes prior to measurement. Use appropriate sized cuff, as a cuff that is too small falsely elevates the reading.
Basic Level Tests (consider for all)
- Complete blood count (CBC)
- Fasting complete metabolic panel (CMP), including: glucose, electrolytes, kidney function, bicarb for acid/base balance, liver panel
- Fasting lipid panel, including: TC, HDL, LDL, triglycerides with attention to the TG/HDL ratio and TC/HDL ratio
- Strongly consider screening all patients with obesity and type 2 diabetes for sleep apnea (home screening options readily available)
- Strongly consider screening for food and sugar addiction
- Thyroid-stimulating hormone (TSH)
- Hemoglobin A1c (HbA1c)
- Urine microalbumin (for patients with diabetes not taking ACE inhibitors or ARBs)
Second Level Tests (consider for higher risk groups)
- 75 or 100 gram oral glucose tolerance test (OGTT)
- Postprandial glucose and insulin tests
- with or without insulin test
- Advanced lipid profile to provide LDL particle size and number (large size and small number are desirable)
- Coronary artery calcium (CAC) score to quantify coronary artery disease
- Serum uric acid
- Serum ferritin for iron stores (especially if vegetarian, low red meat consumption, or status post gastric bypass)
- Vitamin B12 (especially if vegetarian, on long-term metformin use, or status post gastric surgery)
- Vitamin D (especially if status post gastric surgery)
- High-sensitivity C-reactive protein (hsCRP) to check systemic inflammation
- C-peptide levels (consider for patients who have been on long-term insulin to ensure that the patient is still making insulin, especially if the patient does not fit the typical pattern of hyperinsulinemia)
- Body composition scale that can accurately estimate visceral fat
Continuous Glucose Monitor (CGM)
- CGM technology has become more accessible, affordable, and user friendly over time.
- Reactive hypoglycemia and large post-meal spikes are common with standard high carbohydrate dietary patterns, both in insulin resistance and in later stage T2D with beta cell insufficiency. The CGM shows these patterns and how an individualized nutrition regimen improves them.
Patient Selection
- Patients are good candidates for some type of carbohydrate-restricted dietary intervention if they have a problem with overweight, obesity or another metabolic problem.
- Patients should be able and prepared to use a blood glucometer to check serum glucose if on insulin or insulin secretagogues (sulfonylureas and meglitinides) and to communicate with the health care team during the dietary intervention.
- In most cases, patients with an acute, unstable medical condition are not candidates for any dietary intervention.
- Co-existing conditions such as pregnancy or kidney or liver disease may require additional dietary changes or even interdict certain regimens.
