You are seeing a 42-year-old woman who is concerned about her weight. She has previously lost 10 to 15 lb following various commercial and self-directed dietary interventions, but weight was always gradually regained. She is currently at her heaviest weight. She does not have an exercise program in place. The patient feels confused about dietary changes to pursue at this time. She has a history of hypertension and depression both well controlled on stable doses of losartan/hydrochlorothiazide 50 mg/12.5 mg/day and fluoxetine 20 mg/day, respectively. She has a family history of diabetes and is concerned about developing diabetes herself.
A 24-hour diet recall reveals busy days fulfilling home and work responsibilities.
Breakfast is skipped, but mid-morning will have a granola bar and a flavored coffee drink.
Lunch is various greens, diced chicken, sliced avocado, dried fruit, pumpkin seeds, and an olive oil-based vinaigrette.
Mid-afternoon—snacks on nuts and regular soda pop.
Dinner is a pasta dish with a meat- or cream-based sauce, bread with olive oil, salad with various veggies and vinaigrette dressing, and a glass of wine.
After dinner may snack on sweet potato chips, sunflower seeds, nuts, or popcorn.
On physical examination, height is 5′5″ (165 cm), weight 233 lb (106 kg), blood pressure (BP) 130/88 mm Hg, heart rate (HR) 78 bmp, waist circumference 102 cm, and body mass index (BMI) 39.3 kg/m2.
She presents as a well-developed female with upper body fat distribution without Cushingoid features. The remainder of the examination is unremarkable. Laboratory tests:
Complete blood count (CBC), thyroid function test, renal function, and liver function tests are normal.
Nutrition is critical to health. Poor nutrition and a sedentary lifestyle are the main contributors to the rising prevalence of obesity and preventable chronic diseases that impact health. Over half of adults in the United States are overweight or obese and suffer from at least one diet-related chronic health condition including cardiovascular disease (CVD), type 2 diabetes mellitus (T2D), and hypertension, among others.1 Following a healthy calorie-reduced diet that is practical, sustainable, and consistent with the patient’s lifestyle and social norms is foundational to obesity care. It is also notable that despite excess caloric intake in the US population, nutrient deficiencies among adults with obesity are increasingly recognized as a result of poor food quality.2
DIETARY COUNSELING IN THE OFFICE SETTING
Dietary counseling in the office setting can be challenging. Time restraints and low healthcare professional (HCP) confidence in nutrition knowledge can lead to oversimplification of the recommendations provided. For many patients with obesity, dietary education is not enough to effectively promote and sustain changes in eating habits. As a result, a more deliberate and thorough approach is recommended, often implemented by other clinicians such as a registered dietitian nutritionist (RDN). Multidisciplinary teams for obesity care commonly include an HCP (physician and advanced practice providers [nurse practitioner or physician assistant]), RDNs, as well as behavioral health and exercise specialists. Collaboratively, these disciplines can help HCPs by dedicating their time and expertise to develop, implement, and support an individualized care plan for the patient.3 When these disciplines are not readily available within a practice, a “virtual” care team can be created by identifying specialists in the community or healthcare system that can serve as valuable resources for patients. However, with proper guidance, the HCP should be able to initiate meaningful and effective dietary counseling during a dedicated office visit.
TABLE 5.1 Weight Management Resources and Tracking Tools for Internet and Smartphone Appsa
WEIGHT MANAGEMENT RESOURCES AND TRACKING TOOLS FOR INTERNET AND SMARTPHONE APPS
Calorie King www.calorieking.com
Food nutrition database
Photo food tracker
Cooking Light www.cookinglight.com
Cooking Light magazine recipes
Healthy recipes and meal plans
Scans barcodes of items and gives it a nutritional grade with information
Hungry Girl www.hungrygirl.com
Lose It! www.loseit.com
Digital weight management program using cognitive behavioral therapy
Skinny Taste www.skinnytaste.com
Spark People www.sparkpeople.com
Online weight management program
USDA Foodkeeper www.choosemyplate.gov
US Department of Agriculture food tracker that uses the MyPlatefood groups and meal plans
Digital and in-person comprehensive weight management program
aSelected items as of May 2020.
Several tools are available that can facilitate dietary counseling. The US Department of Agriculture (www.choosemyplate.gov/resources/all-resources)4 offers online resources to develop meal plans that can be individualized to a specific calorie goal and eating pattern. There are also several smartphone apps and websites that can help with meal planning and dietary tracking (Table 5.1). Depending upon the electronic literacy of the patient, web-based technologies and mobile devices that help HCPs and patients track progress and support dietary change should be routinely considered.
CALORIE RESTRICTION FOR WEIGHT LOSS
The key principle to achieve weight loss is to create an energy deficit, i.e., to consume fewer calories than are being burned.5 This is consistent with the first law of thermodynamics. Yet, as simple as this seems, successful implementation is limited by multiple factors including individual genetic, physiologic, psychological, environmental, and social determinants that can impact energy balance. As a result, long-term success at losing and maintaining weight with dietary intervention alone is challenging.6 However, understanding the principles of energy balance and how they impact weight loss can establish a sound foundation on which to help patients succeed.
Individual energy requirements (i.e., calories needed to maintain or to lose weight) are determined by many factors including age (drops as we age), sex (higher for men than women), height (the taller you are, the higher your energy needs), and weight (the heavier you are, the higher your energy needs).7 The single largest predictor of energy requirement is muscle mass. Energy expenditure (calories burned) comprises three components:
basal metabolic rate (calories used to maintain bodily functions [60% to 70% of total daily energy expenditure])
thermic effect of food (energy required for digestion [8% to 10% of total daily energy expenditure])
physical activity (both purposeful exercise and nonexercise activity thermogenesis—NEAT—[20% to 30% of total daily energy expenditure])7,8
Both basal and total energy requirements can be measured; however, precise measurement of energy expenditure is impractical in the primary care setting. Several prediction equations, such as the Harris-Benedict equation,9 Mifflin-St Jeor equation,10 and WHO,11 are available to estimate energy expenditure if a more precise estimation is desired for an individual patient. These formulas are often employed by RDNs when calculating dietary requirements. When using one of these equations, the next step is to introduce a caloric restriction for weight loss. Reducing calorie intake by 500 to 750 kcal/day (or 30% of calorie needs) can be expected to lead to weight loss. However, from a practical perspective, use of the American Heart Association/American College of Cardiology/The Obesity Society (AHA/ACC/TOS) recommendations of 1,200 to 1,500 kcal/day for women and 1,500 to 1,800 kcal/day for men is suitable for most patients with obesity as an initial treatment goal. The calorie target can then be adjusted up or down over the first 1 to 2 months of treatment, based on the patient’s weight loss.
Due to biological changes that occur with weight loss, a weight reduction of just 10% of initial body weight leads to a phenomenon called “adaptive thermogenesis.”12 This term describes the observation that an individual who has lost weight burns fewer calories per 24-hour period, compared to an identical individual who is not weight reduced. For patients, this sobering reality means that, once weight loss stabilizes, the patient must maintain the same (lower) level of calorie intake in order to maintain the weight loss they have achieved. Adaptive thermogenesis appears to persist for at least 1 year after weight loss or longer.13 Thus, regardless of which dietary intervention is selected, the patient must be prepared for the weight loss plateau that inevitably occurs after the body’s energy expenditure has dropped to be equivalent with the lower calorie intake that initially led to weight loss.
DIETARY INTERVENTIONS TO INTRODUCE A CALORIE RESTRICTION
The most important dietary factor to lose weight is caloric reduction. As long as calories are reduced, the macronutrient composition of food (percent of carbohydrate, protein, and fat) can vary.5,14 Patients and their HCPs can choose a meal plan based upon the presence of comorbid conditions, taste/food preference, family culture, access, affordability, and overall health. Often, patients will benefit from seeing an RDN for individual dietary counseling. In the section below, the composition and research behind several evidence-based healthy eating patterns are discussed, followed by several shorter-term restrictive diets that are commonly used in clinical practice (Table 5.2).
Healthy Eating Patterns
Despite the confusion that exists regarding healthy eating, the key components of a healthy diet have not changed dramatically over time. The key components include daily consumption of fruits and vegetables, whole grains, fat-free or low-fat dairy products, a variety of protein sources including lean meats and plant-based protein sources, limited intake of saturated fat, and elimination of trans fats. One recent change in the US dietary guidelines was the removal of recommended intake of total dietary fat. Thus, if patients can limit intake of saturated fat, they can increase intake of unsaturated fat from foods such as nuts, avocados, salmon, and other healthy high-fat foods. Several studies have shown that adherence to healthy eating patterns lower the risk for CVD, T2D, and some type of cancers.1
Case Study Discussion
Individualizing dietary recommendations to achieve weight loss and specific health goals can improve adherence. In our case study, there are several health goals that can guide the dietary interventions. If hypertension is the focus, the Dietary Approaches to Stop Hypertension diet (DASH diet) would be a reasonable recommendation.15 If the goal is to improve her hyperglycemia, a Mediterranean-type eating pattern or a meal replacement program could be considered.
Dietary Approaches to Stop Hypertension Diet
The DASH diet was developed as a dietary treatment for hypertension and was then applied for weight loss by reducing overall calories. One trial evaluated the impact of three dietary interventions among 459 subjects with hypertension. The control diet was similar to the current American diet, low in fruits, vegetables, and legumes and high in high-calorie snacks, meat, and saturated fats. A second dietary intervention included high intake of fruits, vegetables, and legumes and low intake of high-calorie snacks. The DASH diet comprised high intake of fruits (4 to 5/day), vegetables (4 to 5/day), legumes, and low-fat dairy products (2 to 3/day) and limited the intake of high-calorie snacks, meats, and saturated and total fat (<25% of calories per day) (Figure 5.1).15
TABLE 5.2 Dietary Counseling in the Office Setting
KEY NUTRITIONAL FEATURES
RESOURCES (ACCESSED MAY 2020)
DASH (dietary approaches to stop hypertension)
High intake of fruits (4-5 servings/day); vegetables (4-5 servings/day); legumes; low-fat dairy
Type 2 diabetes mellitus Prediabetes Metabolic syndrome CVD
Vegetables (3-9 servings/day); fresh fruit (up to 2 servings/day); cereals: mostly whole grain (from 1 to 13 servings/day); oil (up to 8 servings of olive oil/day); fat—mostly unsaturated—up to 37% of the total calories; nuts, legumes, fish, and poultry
Lower blood pressure values were observed with the DASH diet when compared to the control diet. The greatest benefit with the DASH diet was observed in patients with hypertension, compared to those with normal blood pressure, with drops of 11.4/5.5 mm Hg compared to 3.5/2.1 mm Hg, respectively.16 The DASH diet also reduced blood pressure independent of sodium intake.16 However, for the DASH diet to produce weight loss, calorie restriction is needed. In the landmark 4-month ENCORE study, weight loss was 19 lb in the DASH-weight loss group (caloric reduction, exercise, and behavioral support) compared to < 1 lb in the DASH diet group.17
FIGURE 5.1 The DASH (dietary approaches to stop hypertension) food pyramid.
The DASH diet can reduce blood pressure, independent of weight loss, and, when accompanied with caloric restriction, is effective for weight loss and blood pressure reduction.
Low-Fat Diet in the Diabetes Prevention Program
The Diabetes Prevention Program (DPP) was an intensive lifestyle intervention (ILI) study in patients with impaired glucose tolerance, with the goal of avoiding progression to T2D. The dietary intervention introduced a calorie restriction to achieve a weight loss of 5% to 10% of initial body weight. The intervention diet was low in fat (<30 % of total calories), low in saturated fat (<10%), and high in fiber (≥15 grams). The intervention cohort was encouraged to participate in ≥150 minutes of exercise per week and received intensive support from coaches (16 sessions in the first 24 weeks, followed by monthly contact). The control cohort was provided oral and written recommendations on diet and exercise.18