Obesity and Eating Disorders

•Obesity and Eating Disorders
Chapter 14

•Obesity and Eating Disorders

•Prevalence of obesity (BMI ≥30) in American adults aged 20 and older has almost tripled from 13% to 31.4% over the last 40 years

•One of the most common causes of preventable death

• A far less common weight issue is disordered eating manifested as anorexia nervosa or bulimia

•Historically the study of obesity and eating disorders has been separate

•Commonalities between them

•Obesity

•Overweight is defined as having a BMI ≥25

–Related to an excessive body weight, not necessarily excessive body fat

•Obesity is defined as having a BMI ≥30

–Generally assumed to be related to an excessive amount of body fat

•Obesity (cont’d)

•Causes of obesity

–Occurs when people eat more calories than they expend over time

–Why it occurs is not fully understood

–“Set point” theory of weight control

–Some people are able to burn hundreds of extra calories in the activities of daily living to help control weight

–Likely that a combination of genetic and environmental factors is involved

–Obesity (cont’d)

•Genetics

–More than 300 genes have been linked to obesity

–About 30% to 40% of the variance in BMI is attributed to genetics

–About 60% to 70% is attributable to environment

–Genetics are involved in:

oHow likely a person is to gain or lose weight

oWhere body fat is distributed

oResponse to overeating

–Obesity (cont’d)

•Environment

–Rise in obesity without change in gene pool

–Root cause is lifestyle and environment, not biology

–Environmental influences include:

oAbundance of palatable, low-cost, high-calorie– density foods that are readily available in prepackaged forms and in fast food restaurants

oIncreasing consumption of soft drinks and snacks

oGreat proportion of food expenditures spent on food away from home

•Obesity (cont’d)

•Environment (cont’d)

–Influences include:

oGrowing portion size of restaurant meals

oLow levels of physical activity

oIncreases in television watching

oWidespread use of electronic devices in the home, such as computers and video games

–All lead to sedentary lifestyle

•Obesity (cont’d)

•Environment (cont’d)

–Gene–environment interaction

oIn people with a genetic predisposition to obesity, the severity of the disease is largely determined by lifestyle and environmental conditions

•Complications of obesity

–Most common complications of obesity include:

oInsulin resistance, type 2 diabetes, hypertension, dyslipidemia, cardiovascular disease, stroke, gallstones and cholecystitis, sleep apnea, respiratory dysfunction, and increased incidence of certain cancers

–Obesity (cont’d)

•Complications of obesity (cont’d)

–Increases the risk of complications during and after surgery

–Obesity is considered to be a major contributor to preventable deaths in the United States

–Obesity presents psychological and social disadvantages

–Negative social consequences

•Obesity (cont’d)

•Goals of treatment

–Ideally, treatment would “cure” overweight and obesity

–In reality, this ideal is seldom achieved

–A modest weight loss of 5% to 10% of initial body weight is associated with significant improvements in blood pressure, cholesterol and plasma lipid levels, and blood glucose levels

•Obesity (cont’d)

•Goals of treatment (cont’d)

–Modest weight loss:

oIs more attainable

oIs easier to maintain over the long term

oSets the stage for subsequent weight loss

•Obesity (cont’d)

•Evaluating motivation to lose weight

–Objectively identifying who may benefit from weight loss

–Assessing the client’s level of motivation is crucial

–Imposing treatment on an unmotivated or unwilling client may preclude subsequent attempts at weight loss

–Obesity (cont’d)

•Evaluating motivation to lose weight (cont’d)

–Treatment approaches

oA lifestyle approach is the basis of treatment for all people whose BMI is ≥30

Includes diet modification

Exercise

Behavior modification

oPharmacotherapy and surgery may be used in conjunction with lifestyle interventions, based on the individual’s BMI and the presence of comorbidities

•Obesity (cont’d)

•Treatment approaches (cont’d)

–Diet modification

oCornerstone of most weight-loss programs

oFewer calories

oMacronutrient composition

oMicronutrient composition

oNutrition education

oPromoting dietary adherence

•Obesity (cont’d)

•Treatment approaches (cont’d)

–Physical activity

oBenefits of exercise are numerous

oFavorably impacts metabolic rate

oDietary Guidelines recommend adults engage in approximately 60 minutes of moderate- to vigorous-intensity activity on most days of the week to preventweight gain

•Obesity (cont’d)

•Physical activity (cont’d)

–60 to 90 minutes of daily moderate-intensity physical activity are recommended to sustain weight loss

–Promoting exercise adherence:

oSeems to increase with less structure

oStrategies that may promote exercise adherence

Exercise at home

Exercise in multiple short bouts (10 minutes each),

Adopt a more active lifestyle

•Obesity (cont’d)

•Behavior modification

–Focuses on changing the client’s eating and exercise behaviors

–Key behavior modification strategies:

oSelf-monitoring

oGoal setting

oStimulus control

oProblem solving

oCognitive restructuring

oRelapse prevention

•Obesity (cont’d)

•Pharmacotherapy

–Recommended for:

oPeople with a BMI ≥30

oPeople with a BMI ≥27 with comorbid conditions

oPeople with waist circumference greater than 35 inches (women) and 40 inches (men) are also candidates for pharmacotherapy if comorbidities are present

–Obesity (cont’d)

•Pharmacotherapy (cont’d)

–2 drugs approved by the FDA for long-term use have been shown effective in helping promote and maintain weight loss

oAlli is the only over-the-counter drug to gain FDA approval for the treatment of obesity

Expected weight loss is modest (perhaps half of the usual 6 pounds/1 year credited to orlistat)

oPhentermine

Approved for short-term use (≤3 months)

oObesity (cont’d)

•Pharmacotherapy (cont’d)

–Drugs are central nervous system stimulants

–Tolerance may develop after only a few weeks

–Risk of abuse

–Common side effects:

oIncreased heart rate and blood pressure, dry mouth, agitation, insomnia, nausea, diarrhea, and constipation

•Obesity (cont’d)

•Surgery

–Most effective treatment for severe obesity

–Appropriate for clients whose BMI is 35 to 39.9 who have major comorbidities

–Works by:

oRestricting the stomach’s capacity

oCreating malabsorption of nutrients and calories

oA combination of both

•Obesity (cont’d)

•Surgery (cont’d)

–Laparoscopic adjustable gastric banding (LAGB)

oAn inflatable band encircles the uppermost stomach and is buckled

oSmall pouch of approximately 15- to 30-mL capacity is created with a limited outlet between the pouch and the main section of the stomach

oOutlet diameter can be adjusted by inflating or deflating a small bladder inside the “belt” through a small subcutaneous reservoir

•Obesity (cont’d)

•Laparoscopic adjustable gastric banding (LAGB) (cont’d)

–Size of the outlet can be repeatedly changed as needed

–Mortality rate for gastric banding is the lowest of all bariatric procedures

–Successful weight loss after LAGB requires frequent follow-up and band adjustments

oObesity (cont’d)

•Roux-en-Y gastric bypass (RYBG)

–Combines gastric restriction to limit food intake with the construction of bypasses of the duodenum and the first portion of the jejunum

–Creates malabsorption of nutrients

–“Dumping syndrome”

–Superior to gastric resection in both promoting and maintaining significant weight loss

–Major complication with RYBG is anastomotic leak

•Obesity (cont’d)

•Post-surgical diet

–Progression begins with small quantities of sugar-free clear liquids

–Advances as tolerated to full liquids, followed by pureed foods and then a regular diet within 5 to 6 weeks after surgery

–Nutrition therapy guidelines

•Obesity (cont’d)

•Weight maintenance after loss

–Keeping weight off is even harder than losing it

–Diets that lead to weight loss are not necessarily effective for maintaining weight loss

–National Weight Control Registry (NWCR)

–Single best predictor of who will be successful at maintaining weight loss is how long someone has kept their weight off

•Obesity (cont’d)

•Obesity prevention

–Small changes in diet and exercise that total a mere 100 calories/day may be enough to prevent obesity in most of the population

–1 ounce of cheddar cheese/day for 1 year = 10 pound weight gain

•Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not Otherwise Specified (EDNOS)

•Defined psychiatric illnesses that can have a profound impact on nutritional status and health

•Generally characterized by abnormal eating patterns and distorted perceptions of food and body weight

•Continuum of disordered eating

•Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not Otherwise Specified (EDNOS) (cont’d)

•Etiology

–Considered to be multifactorial in origin

–Risk factors:

oDieting, early childhood eating and GI problems, increased concern about weight and size, negative self-evaluation, and sexual abuse

•Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not Otherwise Specified (EDNOS) (cont’d)

•Etiology (cont’d)

–Precipitating factors

oOnset of puberty, parents’ divorce, death of a family member, and ridicule of being or becoming fat

–People with eating disorders often suffer from:

oDepression, anxiety, substance abuse, or body dysmorphic disorder

•Eating Disorders: Anorexia Nervosa (AN), Bulimia Nervosa (BN), and Eating Disorders Not Otherwise Specified (EDNOS) (cont’d)

•Etiology (cont’d)

–Treatment plans are highly individualized

–Antidepressant drugs effectively reduce the frequency of problematic eating behaviors

–Most eating disorders are treated on an outpatient basis

–Nutritional intervention seeks to reestablish and maintain normal eating behaviors

•Nutrition Therapy for Anorexia

•Step-by-step goals of nutrition therapy:

–To prevent further weight loss

–To gradually reestablish normal eating behaviors

–To gradually increase weight

–To maintain agreed-upon weight goal

•Half of those who receive care are expected to recover

•Overall mortality rate is 9.8%

•Nutrition Therapy for Anorexia (cont’d)

•Involving the client in formulating individualized goals and plans promotes compliance

•Large amounts of food may not be well tolerated

•Nutrition Therapy for Bulimia Nervosa

•People with BN tend to have fewer serious medical complications than people with AN because their undernutrition is less severe

•Nutritional counseling focuses on identifying and correcting food misinformation and fears

•Structured and relatively inflexible to promote the client’s sense of control

•Initial meal plan provides adequate calories for weight maintenance

•Nutrition Therapy for Bulimia Nervosa (cont’d)

•Adequate fat is provided to help delay gastric emptying and contribute to satiety

•Calories are gradually increased as needed

•Eating Disorders Not Otherwise Specified

•At least as common as AN and BN

•This group represents:

–Subacute cases of AN or BN

–Binge eating disorder