Low-Carbohydrate Nutrition Approaches in Patients with Obesity, Prediabetes and Type 2 Diabetes

• 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.

• 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.

• 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.

• 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)

• 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

• 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.

• 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.

There are two ways to count carbs: TOTAL CARBS orNET CARBS

Total Carbs

• Look at the serving size and total carbohydrate sections
• In this example, 4 grams carbohydrate = 4 total grams of carbohydrate per 1 cup of cauliflower
• TOTAL CARBS is used when individuals are trying to lose weight most effectively

Net Carbs

• Look at the serving size, total carbohydrate and dietary fiber sections.
• Subtract dietary fiber from total carbohydrate to get the “net carbs.”
• In this example, 4 grams carbohydrate – 2 grams fiber = 2 grams “net carbs” per 1 cup of cauliflower.
• NET CARBS is more often used for individuals trying to lose weight more gradually or maintain body weight.
• Packaged or processed low-carbohydrate foods often contain sweeteners called sugar alcohols (e.g., erythritol, maltitol, xylitol, isomalt) that are carbohydrates. Some people think sugar alcohols can be subtracted similar to fiber when calculating “net carbs,” but most of them contain about half the calories per gram that carbohydrates contain.

Individualizing Carbohydrate Intake Level

• The effective carbohydrate intake level can vary considerably from patient to patient, as can strategies for determining that level.
• The level depends on several factors including age, gender, metabolic rate, insulin sensitivity, activity level, and quality of carbohydrate (glycemic index/load).
• One effective strategy is to start at a level that is effective for most everyone, typically ~20 g of total carbohydrate per day. This level achieves weight loss and ketogenesis in most individuals.
• Then, small amounts of carbohydrate (~5 g) can be added to the daily amount each week in the following situations:
  • As the patient reaches the goal for weight or another goal such as blood glucose control
  • If cravings for carbohydrate might lead the patient to abandon the eating plan
  • If side effects of the eating pattern (e.g., constipation) cannot be managed otherwise and threaten continued adherence.
• Ideally, 5 g of carbohydrate from one type of food (e.g., ½ cup berries, 1 cup of non-starchy vegetable or 1 oz of nuts) is added daily for 1 week.
• If weight loss (or weight stability, if that is the goal) continues, then another 5 g of carbohydrate from the same or another type of food can be added.
• In this manner, the patient can identify a level of carbohydrate intake below which weight loss can be achieved and a higher level at which weight stability can be achieved.

• A low-carbohydrate nutritional approach has a natural appetite reduction effect to ease you comfortably into the consumption of smaller and smaller quantities. Therefore, counting calories is not required.
• Eat when you are hungry and stop when you are comfortably full.
• You do not have to eat if you are not hungry. Skipping meals is acceptable as long as you do not overeat or eat high carbohydrate foods later due to delayed hunger.
• You do not have to eat everything on your plate “just because it’s there.”

• The most important task for the clinician using low-carbohydrate nutrition therapy is to adjust medications to minimize the risk for hypoglycemia and hypotension. Note: For safety and efficacy, the authors feel it is important for the patient to have daily accessibility with the health care team when adjusting medications so daily adjustments can be made if needed.
• Reducing carbohydrate intake potently reduces blood glucose level, which means that diabetes medications can be reduced.
  • Particularly insulin and insulin secretagogues (sulfonylureas, meglitinides) can lead to hypoglycemia and therefore usually need to be reduced at onset of dietary change.
• Reducing carbohydrate intake also leads to water loss, partly from the use of glycogen stores (glycogen is stored with water) and partly from lower insulin levels (insulin, particularly when combined with hyperglycemia, signals the kidneys to retain sodium). As a result, blood pressure can decrease and dehydration can occur if water and sodium are not replenished.
• Insulin and insulin secretagogues should be adjusted ON THE SAME DAY that the patient is starting the new eating plan using the algorithms as guidance.
• Frequency of monitoring thereafter should be individualized based on the patient’s comorbid conditions, concomitant medications, health literacy, age and other factors.
• For patients taking larger doses of insulin or diuretic, clinic visits every 1-2 weeks may be necessary at the beginning, and avenues for communication should be made available if advice is needed between visits.
• Elevations of blood glucose in the 150-250 mg/dl range can be tolerated after medication reductions are made while patients are adapting to low-carbohydrate nutrition and losing weight—this gives a “buffer” from hypoglycemic episodes.
• As weight loss continues, blood glucose levels will decline and further medication reductions may be necessary.
• Visits can be spaced out to monthly when blood glucose or blood pressure is at goal with no or rare hypoglycemia or hypotension episodes. Visits can be spaced further, if desired, when weight loss slows to 1-2 lbs. or less per week.

• For patients with controlled blood pressure and/or controlled edema, consider stopping low-dose or reducing high-dose diuretic medication during first 2–4 weeks to minimize risk for dehydration. Return to prior dose if BP elevates above goal and/or edema recurs.
• Treat symptomatic hypotension (extreme fatigue) or orthostatic hypotension (dizzy or lightheaded when going from lying/sitting to standing) similar to SBP <110 mm Hg.
• If reducing medication already at minimum dose, stop that medication.
• If increasing medication already at maximum dose, add one medication at starting dose.
• Follow diabetes/coronary artery disease/congestive heart failure guidelines regarding choice of agents when starting or stopping medication.

• Myth: Low-carb nutritional approaches are a fad
  Response: Over the past several decades, many randomized controlled trials, both short term and long term (up to 2 years or more), have demonstrated that a low-carbohydrate eating pattern is effective for weight loss, metabolic improvement, and weight maintenance.
• Myth: Low-carb is bad for your heart
  Response: Carefully controlled randomized trials have demonstrated reduction in cardiometabolic risk factors and carotid intimal thickness.
• Myth: Low-carb is not sustainable long-term
  Response: Reducing daily carbohydrate intake has the effect of decreasing appetite and increasing satiation or sense of fullness and corresponding biomarkers. This effect assists in long term maintenance. Randomized trials typically show that patients persist with low-carbohydrate eating plans similarly to comparison diets.
• Myth: Plant foods are reduced
  Response: Non-starchy vegetables (green leafy, cruciferous, zucchini, cucumber, celery, etc.) are the foundational foods of a low-carbohydrate eating pattern and are nutrient dense with abundant amounts of folate, potassium, vitamins and phytonutrients. Proteins or fats can also be obtained from vegetable sources such as nuts, tofu, tempeh, olive oil, avocado and others.
• Myth: Ketosis is dangerous because the brain needs glucose
  Response: Restricting dietary carbohydrates has been an established treatment option for children with hard to control epilepsy since the 1920s and has no proven deleterious effect on cognitive function.
• Myth: Ketone products and fats are necessary to get into nutritional ketosis
  Response: The most important factor to attain nutritional ketosis is to consume a small amount of carbohydrate. Adding ketones or fats or oils is not necessary.
• Myth: Low-carb eating patterns negatively influence kidney function
  Response: This myth stems from the confusion between low-carb eating patterns and high-protein eating patterns. Low-carb does not necessarily mean high protein. Further, for people without existing kidney disease, and for those eating to satiety, higher protein intake does not appear to be related to lower kidney function.

• Long-term sustainability may be improved by behavioral analogies like budgeting. Expectation is not avoidance of all carbohydrates but specific choices of foods low in digestible carbohydrate.
• Cravings for carbohydrate-rich foods are common, and unplanned deviations from any dietary pattern or lifestyle plan are normal and to be expected. Counseling emphasis should be placed on returning to the prescribed eating pattern and developing plans to remove, avoid or respond differently to triggers.
• Discussing in plain language “binge management strategies” and “emotional management strategies” initially and periodically is essential.
• Vegetarian dietary patterns, even vegan patterns, can be adapted to a low-carbohydrate goal with the inclusion of vegetable products which are high in protein content — e.g., soybeans, tofu, tempeh, and vegetable fats such as avocados, olives, nuts, seeds and nut butters.