Learning Objectives
By the end of this section, you will be able to:
- Discuss the pathophysiology of, risk factors for, and clinical manifestations of obesity, anorexia nervosa, and malabsorption
- Describe the diagnostics for and laboratory values monitored in the management of obesity, anorexia nervosa, and malabsorption
- Apply nursing concepts and plan associated nursing care for the patient with obesity, anorexia nervosa, or malabsorption
- Evaluate the efficacy of nursing care for patients with obesity, anorexia nervosa, or malabsorption
- Describe the medical therapies that apply to the care of obesity, anorexia nervosa, and malabsorption
Diet—what you eat and how much you eat—has a dramatic impact on your health. Eating too much or too little food can lead to serious medical issues, including cardiovascular disease, cancer, anorexia, and diabetes, among others. Combine an unhealthy diet with unhealthy environmental conditions, such as smoking, and the potential medical complications increase significantly. This module examines the common nutritional disorders of obesity, anorexia, and malabsorption. Because each disorder creates unique patient care needs, the nurse must be familiar with the appropriate medical care to develop effective care plans.
Obesity
The term obesity is defined as abnormal or excess fat accumulation (World Health Organization, n.d.) and a state of malnutrition by excess (Khanna et al., 2022). It is the result of having a chronic positive energy balance from consuming more calories than are being used by the body. This chronic excess of calories is stored as glycogen in the liver, muscle, and fat cells. Understanding the hormonal control of the digestive system is an important area of ongoing research. Scientists are exploring the role of each hormone in the digestive process and developing ways to target these hormones. Advances could lead to knowledge that may help battle the obesity epidemic.
Pathophysiology
Fatty foods are calorie-dense, meaning that they have more calories than carbohydrates or proteins per unit mass. One gram of carbohydrates has four calories, 1 gram of protein has four calories, and 1 gram of fat has nine calories. The signals of hunger (time to eat) and satiety (time to stop eating) are controlled in the hypothalamus region of the brain. Foods that are rich in fatty acids tend to promote satiety more than foods that are rich only in carbohydrates.
Excess carbohydrate and adenosine triphosphate (ATP) are used by the liver to synthesize glycogen. The pyruvate produced during glycolysis is used to synthesize fatty acids. When there is more glucose in the body than required, the resulting excess pyruvate is converted into molecules that eventually result in the synthesis of fatty acids within the body. These fatty acids are stored in adipose cells—the fat cells in the mammalian body whose primary role is to store fat for later use.
Risk Factors
There are several behavioral, genetic, and social determinants of health that can contribute to obesity. The more risk factors a person has, the greater chance for obesity.
Poor eating patterns or food choices, inadequate sleep, and insufficient activity are all behavioral risk factors for obesity. Eating large portions and consuming large amounts of calorie-dense foods creates an excess of calories needed by the body to survive. An inactive or sedentary lifestyle also makes it easy to consume more calories than needed to remain healthy. Insufficient sleep causes an imbalance of leptin (the hormone that makes you feel full) and ghrelin (the hormone that makes you feel hungry), causing you to overeat.
Genetic risk factors for obesity are still being researched. Some variants in certain genes can cause increasing hunger and increased food intake. In rare instances, a mutation of a single gene can cause inherited obesity within a family (CDC, 2024).
The environment and conditions we live in are called social determinants of health. People who have limited access to healthy food choices or safe access to physical activity are more likely to have obesty. Affordability, social supports, marketing and advertising, and policy are all other community factors that can contribute to obesity.
Other factors that can contribute to obesity are certain illnesses and medications. Microbiome and chemical exposures are also being researched to determine a connection to obesity (CDC, 2024).
Clinical Manifestations
Obesity is defined as having a body mass index (BMI) of 30 or greater (Table 19.1). An individual’s BMI is calculated by dividing their weight (in kilograms) by the square of their height (in meters): kg/m2. BMI classifications range from severely underweight to obese, with three classifications of obesity. BMI should be used alongside other measurements, because it doesn't account for differences based on a person's ethnicity, body type/shape, or age. For example, the traditional BMI chart underestimated the Asian population risk, so their classification has slight alterations. Genetically, Asian and South Asian people have 3 to 5 percent more body fat, which alters the range (Weir & Jan, 2023).
| Weight Status | BMI (kg/m2) |
|---|---|
| Severely underweight | <16.5 |
| Underweight | <18.5 |
| Normal range | 18.5–24.9 |
| Overweight | 25.0–29.9 |
| Obese | ≥30.0 |
| Obesity class I | 30–34.9 |
| Obesity class II | 35–39.9 |
| Obesity class III | ≥40 (also known as severe, massive, or extreme obesity) |
| Asian and South Asian Population | |
| Overweight | 23–24.9 |
| Obesity | ≥25 |
A large waist circumference is an indicator of high levels of visceral fat, or abdominal fat. This type of body fat is found deep in the abdominal wall and surrounds the organs. High levels of visceral fat can lead to heart disease, diabetes, and stroke. Patients can have a normal BMI and still have a large waist circumference, so many practitioners also measure a person's waist circumference to help guide treatment decisions. Weight-related health problems are more common in males with a waist circumference of greater than 40 inches and in females with a waist measurement of greater than 35 inches (NIH, n.d.).
Assessment and Diagnostics
A thorough nutritional assessment provides information about an individual’s nutritional status, as well as risk factors for nutritional imbalances, including obesity. Diagnostics can be used to evaluate for comorbid conditions that can occur with obesity.
Diagnostics and Laboratory Values
Diagnostics and laboratory studies will generally focus on ruling out other comorbidities or health conditions, according to the subjective and objective assessment data found. Laboratory studies that may be performed include a basic metabolic panel, liver function study, kidney function study, lipid profile, thyroid-stimulating hormone and other hormone-level studies, vitamin D levels, urinalysis, hemoglobin A1c, and C-reactive protein. An electrocardiogram may be ordered to evaluate cardiac rhythm and function. A sleep study can evaluate for sleep apnea, if warranted (Panuganti et al., 2023). Other potential diagnostic studies include
- computed tomography (CT) scan to evaluate internal organ structure
- dual x-ray absorptiometry (DEXA) scan to measure bone density
- hydrostatic weighing (weight while submerged in water) to more accurately measure body fat
- skinfold thickness evaluation to measure subcutaneous body fat
Nursing Care of the Patient with Obesity
Care for patients with obesity is individualized, according to any underlying causes of obesity and any comorbid conditions. Treatment includes behavioral interventions, nutritional modification, medications, and surgical intervention, if appropriate (Panuganti et al., 2023). Nursing management focuses on reinforcement of treatment, patient support, and health teaching and education.
Recognizing Cues and Analyzing Cues
Targeted subjective information focuses on screening for any underlying causes contributing to obesity, such as childhood weight history, family history, sleep patterns, prior weight loss efforts and results, physical activity, surgical history, social history of alcohol and tobacco use, and medications that can cause weight gain. An associated past medical history may reveal thyroid disease, diabetes, cardiovascular disease, or psychosocial disorders such as mood disorders (Panuganti et al., 2023).
Objective assessment data are obtained through inspection, auscultation, and palpation. The nurse begins the physical examination by making general observations about the patient’s status. Height, weight, BMI, and waist circumference should be accurately measured and documented. Focused findings may include a crowded oropharynx, abdominal pannus, pedal and/or tibial edema, abdominal striae, distant breath and cardiac sounds, gynecomastia, signs of venous insufficiency, and gait abnormalities (Panuganti et al., 2023).
Prioritizing Hypotheses, Generating Solutions, and Taking Action
The patient’s psychosocial well-being and motivation to comply with treatment are important factors in weight reduction. Ways the nurse can reinforce treatment include encouraging healthy eating, reinforcing the importance of positive self-esteem and self-care, developing a food diary for the patient to use, and being realistic about weight-loss goals. Promote increased physical activity through participation in exercise programs, including group exercise programs, to provide the patient with feelings of support. Allow the patient to express their feelings about their weight, appearance, and food, and positively reinforce the patient’s efforts to promote weight loss. Educating the patient, family, and caregivers about the importance of healthy sleep habits, eating schedules, portion control, and a healthy diet can help positive reinforcement and adherence continue after discharge.
Evaluation of Nursing Care for the Patient with Obesity
The process of evaluating nursing care requires the nurse to evaluate each intervention, how the patient responded to it, whether goals were met. It entails a reflection of what could have been done differently to improve the patient’s state. Goals of nursing care for a patient with obesity may include
- The patient will have 30 minutes of activity three times a week.
- The patient will have a reduction in depression symptoms within 2 months.
- The patient will have a reduction in snoring within 6 months.
- The patient will have an increased tolerance to activity in 1 month.
- The patient will lose 10% of their body weight in 4 months.
Each goal should have a timeline, and goals can be short term or long term. As the patient reaches goals, a new goal should be made with the patient to direct the next portion of care.
Evaluating Outcomes
The primary patient outcome related to obesity is management of weight loss. The nurse evaluates the patient’s meal choices, level of activity, and engagement of care. If the patient is struggling with an exercise regimen, for example, the nurse should evaluate if the patient is not engaged enough to participate or if the exercise is too complicated for the patient to do.
Medical Therapies and Related Care
The goal of obesity treatment is to assist the patient to reach and maintain an ideal weight for their height, body build, and their health. This can improve the overall health and lower the risk of developing complications related to obesity. Medical therapy includes dietary modification, behavior intervention, medications, and possible surgical intervention. The collaborative, interdisciplinary health team may include a dietitian or nutritionist, endocrinologist, bariatric nurse, and behavioral counselor to help the patient understand and make changes in their eating and activity habits. The goal is to create a permanent lifestyle change for the patient, not just something temporary.
The initial treatment goal is incorporation of a low-calorie diet, with frequent emphasis on patient adherence. Maintaining realistic weight loss goals increases patient success. Cognitive therapy, motivational interviewing, and interpersonal psychotherapy may also be used to increase patient compliance.
Behavioral Interventions
The provider may encourage the patient to participate in behavioral modification therapy (BMT) with a therapist who has experience in bariatrics. Through BMT, the patient will learn structured ways to improve lifestyle habits, such as diet choices, exercise, and other behavior choices (Olateju et al., 2021). BMT will also teach the patient about self-monitoring, goal setting, stimulus control, stress management, cognitive restructuring, and problem solving. Patients who participate in BMT are more likely to succeed in long-term weight loss (Olateju et al., 2021).
Medications
Anti-obesity medications may be prescribed for patients with a BMI of 30 or higher or those with a BMI of 27 or higher who have comorbidities. The most common first-choice medication prescribed is orlistat, because of its limited absorption and lack of systemic effects (Panuganti et al, 2023). Other commonly prescribed, U.S. Food and Drug Administration (FDA)-approved medications are listed in (Table 19.2).
| FDA-Approved Weight Loss Medication | Mechanism of Action | Contraindications |
|---|---|---|
| Orlistat (Alli, Xenical) | Blocks absorption of fat during digestion | Digestive problems, cholestasis, hypothyroidism, kidney stones, seizures |
| Phentermine-topiramate (Qsymia) | Lessens hunger; makes patients feel full sooner | Glaucoma, hyperthyroidism, mood disorders, cardiac disease, kidney disease Do not use if pregnant or breastfeeding. |
| Naltrexone-bupropion (Contrave) | Lessens hunger; makes patients feel full sooner | Hypertension, seizures, opioid-use disorder, history of eating disorders May increase suicidal ideation |
| Liraglutide (Saxenda, Victoza) | Mimics glucagon-like peptide-1 (GLP-1), which regulates appetite in the brain | May increase risk of pancreatitis |
| Semaglutide (Ozembic, Rybelsus Wegovy) | Mimics GLP-1, which regulates appetite in the brain | Not for use in combination with other GLP-1 agonists or weight loss products; may increase risk of pancreatitis |
| Setmelanotide (Imcivree) | May reduce appetite and increase resting metabolism | Only for use by patients with proopiomelanocortin deficiency, proprotein convertase subtilisin/kexin type 1 deficiency, or leptin receptor deficiency |
Surgery
The branch of medicine that researches and treats obesity is called bariatrics. Bariatric surgery is a consideration for patients with a BMI of 40 kg/m2 or patients with a BMI of 35 kg/m2 with significant health issues that would be expected to improve with weight loss. Before preoperative consideration, the patient must show efforts to lose weight for a period of 12 months or more. A dietitian will collaborate with the patient in these efforts and start preoperative teaching for bariatric surgery at the appropriate time. Two common procedures performed are a vertical sleeve gastrectomy and Roux-en-Y gastric bypass.
A vertical sleeve gastrectomy is a surgical procedure in which a portion of the stomach is removed, and the size of the stomach is reduced to 3 to 4 ounces (Figure 19.2). This can be done laparoscopically or as an open surgical procedure. A vertical sleeve gastrectomy also reduces the production of ghrelin, resulting in the patient feeling full quickly after consuming a small amount of food. Complications patients may experience from this type of surgery include gastroesophageal reflux, strictures, and gastric ulcers from nonsteroidal anti-inflammatory drug (NSAID) use or smoking.
A Roux-en-Y gastric bypass is the most common type of malabsorption bypass surgery performed in the United States. The procedure involves creating a small, 1-ounce gastric pouch at the gastroesophageal junction, separating the rest of the stomach and bypassing the duodenum to connect the gastric pouch to the lower segment of the small intestine (Figure 19.3). Bypassing part of the small intestine causes malabsorption of vitamins, macronutrients, and minerals. The combination of restrictive stomach size and malabsorption causes rapid weight loss. Complications of gastric bypass include gastric ulcers from NSAID use or smoking, dumping syndrome, steatorrhea, stricture, reactive hypoglycemia, and vitamin and mineral deficiencies.
Link to Learning
Dumping syndrome is a common complication of bariatric surgery.
Anorexia Nervosa
The eating disorder anorexia nervosa is characterized by the maintenance of a body weight well below average through severe dietary restriction and/or excessive exercise. Individuals with anorexia nervosa often view themselves as overweight even though they are not. This distorted body image is considered a type of body dysmorphia, which is a mental illness characterized by constant worrying over a perceived or slight defect in appearance. Estimates of the prevalence of anorexia nervosa vary from study to study but generally range from just under 1 percent to just over 4 percent in females. Generally, prevalence is considerably lower among men.
Although anorexia nervosa occurs in people from many cultures, White girls and women from Western societies tend to be the most at-risk population. Recent research indicates that girls between the ages of 15 and 19 years are most at risk, and it has long been suspected that eating disorders are culture-bound phenomena that are related to messages of a thin ideal often portrayed in popular media and the fashion world. Although social factors play an important role in the development of eating disorders, there is also evidence that genetic factors may predispose people to this disorder.
Pathophysiology
Anorexia nervosa deprives the body of the basic nutrition necessary to properly function. Studies have evaluated the role of biological and environmental factors that contribute to the development of anorexia nervosa. Patients with anorexia nervosa have deficits in dopamine and serotonin neurotransmitters, which are responsible for eating behavior, reward, impulse control, and neuroticism (Moore & Bokor, 2023). Endocrine abnormalities can include decreased production of thyroid hormones from lack of iodine, increased production of cortisol in response to stress on body from lack of nutrition, and decreased levels of gonadal hormones, such as estrogen and testosterone. Patients often have comorbid psychiatric disorders, such as generalized anxiety disorder and major depressive disorder (Moore & Bokor, 2023).
Clinical Manifestations
Patients with anorexia nervosa usually report symptoms of endocrine dysfunction, such as amenorrhea (cessation of the menstrual period), cold intolerance, fatigue, loss of libido, irritability, and extremity edema. Many will also exercise compulsively for extended periods of time and have restrictive behaviors related to food intake, such as calorie counting and portion control (Moore & Bokor, 2023).
Assessment, Diagnostics, and Laboratory Values
Anorexia nervosa is associated with several important negative health outcomes, namely, bone loss, heart failure, kidney failure, reduced function of the gonads, and, in extreme cases, death. Furthermore, there is an increased risk for several psychological problems, including anxiety disorders, mood disorders, and substance misuse. Assessment and treatment of anorexia nervosa focus on understanding the patient’s experience and concerns, as well as determining potentially reversible causes. Psychiatric evaluation and diagnosis of anorexia nervosa are based on criteria provided by the American Psychiatric Association. These criteria include the patient having a distorted view of themselves and their condition, intense fear of gaining weight, and a significantly low body weight resulting from severe conscious restriction of calories.
Initial laboratory tests will focus on disease complications based on signs and symptoms gathered from assessment data. Basic laboratory work will include complete blood cell count (CBC), complete metabolic profile, 25-hydroxyvitamin D concentration, testosterone (male patients), and thyroid-stimulating hormone. Urine testing will evaluate beta-hCG in females, as well as a drug screen (illicit and prescription).
An echocardiogram will be completed for patients with cardiopulmonary symptoms, such as dyspnea, syncope, or heart murmur, to assess for arrhythmias. A CT scan of the abdomen may also be done for patients with prolonged amenorrhea or to rule out superior mesenteric artery conditions that could affect the duodenum.
Nursing Care of the Patient with Anorexia
Although anorexia nervosa is a treatable disease, patients have a high risk for relapse. Close monitoring, constant positive reinforcement, and patient education are important interventions to optimize outcomes.
Recognizing Cues and Analyzing Cues
The nurse providing care to a patient with anorexia nervosa uses subjective and objective data to optimize care. Subjective data may include body image disturbances, GI complaints, dizziness, feeling cold, sleep problems, menstrual problems, and muscle weakness. Objective data may include general body emaciation, dry skin, cold extremities, poor wound healing, lower extremity edema, and abnormal laboratory values. Vital signs should focus on blood pressure and apical heart rate.
Prioritizing Hypotheses, Generating Solutions, and Taking Action
Patients being treated for anorexia nervosa in the hospital setting are usually medically unstable due to potential electrolyte imbalances; they may have an increased risk of self-harm due to existing psychiatric disorders. Safety measures the nurse should take to ensure patient safety include following facility protocol for suicide precautions to ensure the patient environment is safe, supervising feedings, and frequent collaboration with the interdisciplinary team.
Evaluation of Nursing Care and Outcomes for the Patient with Anorexia
The nurse will evaluate each nursing action and determine how the patient responded. In addition, the nurse determines if the goals are met using patient input. Among possible goal examples are that the patient will eat 75 percent of their meals every day; the patient will gain 1 pound a week; and the patient will state three things they like about their body every day.
The primary patient outcome for anorexia nervosa management is an increase in caloric intake to sustain healthy bodily function. Collaboration with psychiatry is important in understanding and overcoming the patient’s negative thoughts about food and body image.
Medical Therapies and Related Care
Nutritional rehabilitation and psychotherapy are the primary components of treatment for anorexia nervosa. In addition to the nurse and provider, the interdisciplinary team can include a dietitian, psychologist, social worker, and gastroenterologist. In some instances, pharmacotherapy may help. Antipsychotics, such as olanzapine, may help with weight restoration. Patients with comorbid psychiatric conditions may be prescribed serotonin reuptake inhibitors along with psychotherapy.
Malabsorption
The term malabsorption refers to the condition whereby the GI tract is unable to properly absorb nutrients, such as proteins, carbohydrates, fats, vitamins, minerals, or trace elements. This can occur with one vitamin or macronutrient, several, or all.
Pathophysiology
Malabsorption occurs when an abnormality in the GI tract impedes the body from absorbing nutrients correctly. Most absorption occurs in the large intestine, but some occurs in the small intestine and stomach. Malabsorption can occur at any phase of the digestion: luminal, mucosal, or postabsorptive (Table 19.3).
| Phase of Digestion | Process |
|---|---|
| Luminal | Carbohydrates, dietary fats, and proteins are hydrolyzed and solubilized by secreted digestive enzymes and bile. |
| Mucosal | Intestinal epithelial cells transport digested products from the lumen into the cells. |
| Postabsorptive | Reassembled lipids and other nutrients are transported from intestinal epithelial cells to other parts of the body. |
Clinical Manifestations
The most common clinical manifestations of malabsorption are diarrhea, steatorrhea (fatty stool), fatigue, abdominal bloating and cramping, increased flatulence, and unintentional weight loss. If the malabsorption is of a vitamin, the patient will have symptoms of that vitamin deficiency (Table 19.4). If the malabsorption is of a macronutrient, the patient will have symptoms resulting from a lack of fat, carbohydrate, or protein.
| Vitamin/Mineral Deficiency | Symptoms |
|---|---|
| Iron | Anemia |
| Vitamin A | Night blindness |
| Vitamin B12 | Anemia, poor balance |
| Vitamin K | Abnormal bleeding, ecchymosis |
| Vitamin D | Osteopenia, osteomalacia, bone pain, motor weakness |
| Calcium | Secondary hyperparathyroidism, tetany |
| Magnesium | Tetany |
| Vitamin B1 (thiamine) | Peripheral neuropathy |
| Vitamin B5 | Motor weakness |
| Vitamin B7 (biotin) | Seizures |
Assessment, Diagnostics, and Laboratory Values
The nurse will obtain a history including health history and a general physical assessment, including the course of symptoms. Medical history may reveal a disorder that causes malabsorption, such as celiac disease, lactose intolerance, pancreatic insufficiency, ulcerative colitis, parasite infection, inflammatory bowel disease, or Whipple disease.
When malabsorption is suspected, general testing is done to try to narrow down areas that need more specific testing. Blood tests will include a comprehensive metabolic panel to check liver and kidney function and evaluate for electrolyte imbalances; a CBC count will evaluate for anemia, zinc, phosphorous, albumin, and magnesium; and vitamin levels will be evaluated.
Fecal testing may be done to evaluate for fat malabsorption. Jejunal aspirate samples will be cultured to check for bacterial overgrowth in the small intestine. A breath test can evaluate for carbohydrate malabsorption. Some examples of studies for specific conditions include
- colonoscopy and biopsy to diagnose ulcerative colitis
- CT scan to diagnose pancreatitis
- endoscopic retrograde cholangiopancreatography (ERCP) to diagnose pancreatic insufficiency in patients with a history of pancreatitis or alcohol use disorder
- endoscopy to diagnose Crohn disease or jejunoileitis
- magnetic resonance elastography to diagnose liver fibrosis or stiffness
- magnetic resonance cholangiopancreatography to diagnose exocrine pancreatic insufficiency
Nursing Care of the Patient with Malabsorption
The care of the patient with malabsorption focuses on ongoing assessments and patient and family education. If the cause of malabsorption is determined, then more focused care can be provided. A general measure that may be helpful to the patient is food journaling, logging symptoms and the time symptoms occur.
Recognizing Cues and Analyzing Cues
Patients with malabsorption may present with common GI symptoms, along with symptoms of vitamin or mineral deficiencies. Objective data may include signs of muscle wasting, distended abdomen, ascites, ecchymosis, peripheral neuropathy, oral mucus membrane ulcers, peripheral edema, a positive Chvostek or Trousseau sign, and pale skin. Evaluate vital signs with a focus on blood pressure. The nurse may note orthostatic hypotension. It is important to ask the patient about their medical and surgical history and the history of their symptoms, including when they began and how they have progressed. A history of GI surgery, especially weight loss surgery, also increases a patient’s risk for malabsorption.
Link to Learning
Watch this video to learn more about the signs and symptoms of malabsorption along with causes and treatment of the condition.
Prioritizing Hypotheses, Generating Solutions, and Taking Action
The patient’s GI symptoms may be the primary condition or a symptom of a disease. The nurse will assist with diagnostic testing and educate the patient about any diagnostic procedures performed. The nurse will provide emotional support to the patient (Zuvarox & Belletieri, 2020).
Evaluation of Nursing Care and Outcomes for the Patient with Malabsorption
Evaluation of care centers around improvement of symptoms and diet modifications. Accurately understanding the cause of malabsorption can improve the nurse’s ability to evaluate outcomes. The nurse evaluates if the patient is receiving adequate nutrition. The nurse monitors vital signs and completes a physical assessment to evaluate symptom improvement. Laboratory blood values can reveal improvements in vitamin, mineral, and electrolyte balance.
Medical Therapies and Related Care
Medical treatment is focused on finding and treating the underlying cause of malabsorption, avoiding any food triggers, and symptom management. Treatment can vary from dietary changes and supplementation to surgical intervention, if necessary. Consider referral to a gastroenterologist.