Energy Balance and Healthy Body Weight

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Chapter 9 - Energy Balance and Healthy Body Weight
• Being both overweight and underweight present risks to health
– Overweight: over fatness of moderate degree
• BMI 25.0 29.9
– Underweight: too little body fat
• BMI<18.5
• Body composition
– Proportion of muscle, bone, fat
– Controlling body composition is more important than controlling body weight
• Can be controlled only by controlling behavior
The Problems of Too Little or Too Much Body Fat
• In the U.S.
– Too little body fat is not a widespread problem
– Obesity is an escalating epidemic
– In the year 2000
• 64% of U.S. adults were overweight
• 30% were obese
• One of every seven U.S. children and teenagers is overweight
What Are the Risks of being underweight?
• Underweight people are at risk of dying
– During a siege or famine
– When hospitalized if they have to go without food for days at a time when undergoing tests for
surgery
• Underweight people are at greater risk when fighting a wasting disease
– People with cancer often die from starvation, not the cancer itself
• Underweight people should gain body fat as an energy reserve and to acquire reserves of
nutrients that can be stored
What Are the Risks of being Overweight?
• Obesity increases the risk of, for example
– Hypertension, diabetes, heart disease
– If the excess weight is fat and not muscle, even moderately overweight people are at increased
risk
•Body weight is not the only disease risk factor
– Inheritance, abstinence from smoking, and cardiovascular fitness will determine who among the
obese stays well and who falls ill
• 300,000 people in the U.S. die each year from obesity related diseases
• 70+% of obese people suffer from at least one other major health problem
• ˜50% of hypertension cases are due to excess weight
• As of now, only tobacco contributes to more preventable diseases and premature deaths
• Obesity triples the risk of diabetes
– Even moderate weight gain increases diabetes risk
– The risk appears to be greater for people of European ancestry than for African Americans
• Additional obesity related risks include
– Abdominal hernias, arthritis, complications in pregnancy and surgery, flat feet, gallbladder
disease, gout, high blood lipids, liver malfunction, respiratory problems, sleep apnea, some
cancers, varicose veins, high accident rate
– Even after accounting for diagnosed diseases, the risk of death from other causes remains ˜2x as
high for people with lifelong obesity
• Even moderate weight loss reduces risk
• Central Obesity
– Fat that collects deep within the central abdominal area of the body (visceral fat)
– Increases the risk of diabetes, stroke, hypertension, coronary artery disease
– Central obesity may increase the risk of death from all causes as compared to fat accumulations
elsewhere in the body
• Central Obesity
– Visceral fat is readily released into the blood stream
– Fat layers lying just beneath the skin (subcutaneous fat) of the abdomen, thighs, hips, and legs
release fat slower than visceral fat
• Men and postmenopausal women are more prone to develop central obesity
• Women in their reproductive years are more prone to carrying their fat around the hips and
thighs
• Smokers are more likely to carry their fat centrally
• Moderate to high alcohol intake correlates positively with central obesity
• Physical activity correlates negatively with central obesity
• How Fat Is Too Fat for Health?
– The answer is different for different people
– However, guidelines have been developed
• BMI (body mass index) defines average relative weight for height in people older than 20 years
– Often correlates with degree of body fatness and disease risk
• Waist circumference reflects the degree of visceral fatness in proportion to body fatness
• Disease risk profile
– Takes into account whether the person has hypertension, type 2 diabetes, elevated blood
cholesterol, smoking
– The more risk factors and the greater the obesity the greater the need to control body fatness
• Cardiovascular fitness improves health and longevity, independent of BMI
• Normalweight fit people have the lowest risk of death from chronic diseases
• Among those who are overweight and have diabetes, fitness may be a greater determinant of the
risk of death than overfatness
• Social and Economic Costs of Obesity
– Fat people are more likely to be judged on their appearance than on their character
– Our society places enormous value on thinness, especially for women
• Fat people are less sought after for romance, less often hired, less often admitted to
college, pay higher insurance premiums, pay more for clothing
• ˜30% 40% of all U.S. women and ˜20% 25% of U.S. men are trying to lose weight
– ˜5% of all people who lose weight maintain their losses
• Prejudice often stereotypes obese people as lazy, stupid and self indulgent
• Obese people suffer emotional pain when treated with hostility and contempt
The Body’s Energy Balance
• When more food energy is consumed than needed, excess fat accumulates in the fat cells of the
body’s adipose tissue
• Daily energy balance Change in energy stores = energy in energy out
• Energy In and Energy Out
– The energy in foods and beverages contribute to the “energy in” side of the energy balance
equation
– The “energy out” side of the equation requires knowing about a person’s lifestyle and
metabolism
• Estimated Energy Requirements (EER)
– Apply only to the characteristics of the “reference man and woman”
• Reference man: “active” physical activity level, 22.5 BMI, 5’10”, 154 lb.
• Reference woman: “active” physical activity level, 21.5 BMI, 5’4”, 126 lb.
• Taller people have a greater surface area which allows more energy to escape as heat
– Therefore, need proportionally more energy than shorter people
• Older people need less energy then younger people
– Due to a slower metabolism and reduced muscle mass, which are in part due to decreased
physical activity
– On average, energy need diminishes 5% per decade beyond the age of 30 years
How Many Calories Do I Need Each Day?
• Energy input should equal energy output
– Track foods and beverages consumed for a week; if your weight does not change you are in
energy balance
• Energy output
– Basal metabolism
• Sum total of energy expended on all of the involuntary activities needed to sustain life
– Excludes digestion
– Voluntary activities
– Thermic effect of food
• 5%10% of a meal’s energy is expended in stepped up metabolism in the 5+ hours after a
meal
• Basal metabolic rate (BMR)
– Varies from person to person
– Varies with activity level
– Positively correlates with thyroxin secretion
– Lowest during sleep
• Basal metabolic rate (BMR)
– In the short term BMR will not increase
– Over the long term, increasing voluntary activities will increase BMR
– Lean tissue has a higher BMR then fat tissue
• The DRI Method of Estimating Energy Requirements (EER)
– Men: kg body weight x 24= cal/day
– Women: kg body weight x 22 = cal/day
• Gender
– Women generally have less lean body mass than men
– Menstrual hormones raise BMR just prior to menstruation
• Age
– BMR declines by an average of 5% per decade
• Physical activity
– The DRI clusters activities according to their typical intensity
• Body size and weight
– The higher BMRs of taller and heavier people need to be factored in when estimating EER
How to Calculate Your EER
Body Weight versus Body Fatness
• Body Mass Index (BMI)
– Correlates with body fatness
– Used to evaluate health risks associated with underweight or overweight
– In general, for adults
• Overweight is defined as a BMI of 25.0 29.9
• Obesity as BMI =30
• Body Mass Index (BMI)
BMI =(weight in kg)/(height in m 2 )
BMI = ((weight in lb)/(height in in 2 )) x 705
• Risks associated with a high BMI appear to be greater for whites than for blacks
• Health risks associated with obesity do not become apparent until a BMI of 37
• BMI values are not very useful for evaluating nonobese people’s fatness
• BMI values fail to distinguish between how much of a person’s weight is fat and where the fat is
located
– Athletes: highly developed muscle falsely increases BMI
– Pregnant and lactating women: increased weight is normal during childbearing
– Adults over 65: because BMI values are based on data collected from younger people and
because people shrink with age
• Measures of Body Composition and Fat Distribution
– Anthropometry
• Fat fold tests
• Waist circumference
– Density
• Underwater weighing
– Conductivity
• Bioelectrical impedance
• Radiographic techniques
– Dual energy Xray absorptiometry (DEXA)
• How Much Body Fat Is Ideal?
– Varies with gender, age, lifestyle, age of life
– Percent body fat
• Man of normal weight: 12% - 20%
– Overfat: greater than 22%; 25% if over 40 years
• Female of normal weight: 20% - 30%
– Overfat greater than 32%; 35% if over 40 years
The Mystery of Obesity
• Many factors, some of them conflicting, correlate with obesity
– Cause of obesity is difficult to determine
• Factors that correlate with obesity
Birth order, number of brothers, divorced/single parents, nonprofessional parents, early
menstruation, ethnicity
•More factors that correlate with obesity
exposure to a variety of foods, Fastfood, fat, protein, and carbohydrate intake, increased wealth,
less leisure time, international travel, geographic location, lower education level, lower social
class, maternal famine, obesity during gestation, meal skipping, meals away from home, napping
habits, sleep deprivation, reduced alcohol intake, increased alcohol intake, sedentary behavior,
television watching, substandard housing, etc.
– Sleep deprivation
– Reduced alcohol intake
– Increased alcohol intake
– Sedentary behavior
– Television watching
– Substandard housing
– Etc.
Why Did I Eat That?
• Eating behavior seems to be regulated by mechanisms that stimulate eating and mechanisms
that signal the body to cease or refrain from eating
• “Go” Signals Hunger and Appetite
– Hunger
• Sensation that signals a need for food
• Occurs roughly 46 hours after eating
– After the food has left the stomach and much of the nutrient mixture has been absorbed
• Triggered by a contracting empty stomach, an empty small intestine, the stomach
hormone ghrelin produced between meals, and chemical and nervous signals in the brain
• Other factors influencing hunger
– Nutrients in the blood stream
– Size and composition of the previous meal
– Weather
• Heat reduces food intake
• Cold increases food intake
– Exercise
– Sex hormones
– Illnesses
– Etc.
• The hunger response quickly adapts to changes in food intake
• At some point in food deprivation, hunger returns and can lead to bouts of overeating that
overcompensate for the calories lost during the deprivation period
• Just as the stomach can adapt to small meals it adapts to larger quantities of food
– This might partly explain the increase in obesity
– Popular demand has led to larger servings of food; stomachs have adapted to accommodate
them
• Appetite
– The psychological desire to eat
– Can be experienced without hunger
• The sight and smell of food can stimulate the brain’s endorphins, molecules that create
an appetite despite an already full stomach
– Illness or stress may result in the loss of appetite in a person in physical need of food
• Other factors affecting appetite
hormones, inborn appetites, learned preferences, aversions, timings, customary eating habits,
social interactions, some disease states, appeitite stimulants, depressants, mood-altering drugs,
environmental conditions
• “Stop” Signals - Satisfaction and Satiety
– Satiation
• The perception of fullness that builds throughout a meal
– Eventually reaching the degree of fullness and satisfaction that halts eating
• Stomach stretching to accommodate a meal triggers receptors in the stomach to send
signals to the brain that tell it that the stomach is full
• The brain also detects nutrients in the blood
• Satiety
– The perception of fullness that lingers after a meal
– Suppresses hunger
• Hunger strongly stimulates eating behavior
• Satiation and satiety exert weaker control over food intake and can be ignored
• Leptin: A Satiety Hormone
– Leptin
• An appetitesuppressing hormone
• Produced by adipose tissue
• Travels to the brain
• Directly linked to appetite and body fatness
• Some production by the stomach
– Where it may contribute to satiety
– Gain of body fatness stimulates leptin production
• Reducing food consumption; resulting in fat loss
– Loss of body fat reduces leptin secretion
• Increasing appetite
• Leptin’s roles
– Signals the female reproductive system about fat reserves
– May assist in sexual maturation
– Stimulates growth of new blood vessels in the cornea of the eye and elsewhere
– Constricts arteries
– Plays a role in the formation of blood cells
– Helps support immune system function
• Energy Nutrients and Satiety
– At least 15 studies show that a low glycemic index diets reduced or delayed hunger
– 16 studies have found the opposite or no effect
• Showed that diets based on refined grains are just as satisfying as diets based on low
glycemic index diets
• Of the energy-yielding nutrients, protein may be the most satiating
– May account for the popularity of high-protein weight loss diets
• Fat is also known for its satiety effects
• Protein and fat trigger the release of an intestinal hormone that slows stomach emptying and
prolongs feelings of fullness
• Satiety is also associated with
– High fiber foods
– Water
– Foods that have been puffed up from air
Inside-the-Body : Causes of Obesity
• Selected Metabolic Theories of Obesity
– Attempt to explain the ease with which people gain/lose weight when eating more/less food
energy than they expend
• Genetics and Obesity
– In rare instances, the primary cause of obesity is genetic
– There can be an inherited tendency toward developing obesity
• However, genes are not the sole determining factor
• Children with at least one obese parent have a 40%-70% chance of becoming obese
• While genetics influences a person’s tendency to become obese, lifestyle choices determine if
the tendency is realized
• The search for obesity treatments through genetic research has been disappointing
Outside-the-Body : Causes of Obesity
• People can override signals of satiety and hunger
• People seek ease and as a result decrease their energy expended in activities required for daily
living
• External Cues to Overeating
– Variety influences animals, including humans, to eat even when they are not hungry
• Especially when presented with a wide variety of delectable foods, such as sweets,
snacks, etc.
• Consumption of a wide variety of vegetables but few treats correlates with lower body
fatness
• Overeating also occurs in response to
Loneliness, Yearning, Craving, Addiction, Compulsion, Depression, Time of Day, Stress
• Foods that stressed people eat are often referred to as comfort foods
• The aforementioned factors cannot fully explain obesity development
– Many thin people are susceptible to them
– Some people cannot eat at all when under stress
• Food Price, Availability, and Advertising
– High calorie fast foods are relatively inexpensive, widely available, heavily advertised, and (to
some people) delicious
• A steady diet of them correlates with obesity
• It must be asked if price, availability, and advertising can attract consumers of fast
foods, can they also attract consumers of healthy foods?
• One estimate suggests that 40% of the recent jump in U.S. body weights may be solely due to
lower food prices
• Occasional indulgence in high calorie foods does not mean the eater will become obese
– Moderation and common sense are the keys
• Physical Inactivity
– Some people are obese not because of how much they eat, but because they move too little
– Diet histories of obese people often report energy intakes similar to, or even less then, those of
others
• It is the lack of physical activity that results in an energy surplus
• Such inactivity is a recent phenomenon
– 100 years ago, 30% of the energy used in farm and factory work came from human muscle
power: today only 1% does
• The same trend follows elsewhere
• It takes active muscle movement to achieve energy balance
• Despite the benefits to body composition and health from regular physical activity, the U.S. is
experiencing an epidemic of inactivity
•Table 9-5 : Energy Spent in activities (shows number of calories burned for different activities)
• End of Story?
– Insofar as the causes of obesity there is no clear evidence as to which factor(s) bears
responsibility
– For most people, the best way to obtain a healthy body weight is to
• Maintain a proper diet
• Engage in daily physical activity
• Practice behavior modification
Think Fitness: Activity for a Healthy Body Weight
• According to the NIH, moderate exercise is defined as using ˜150 calories per day (1,000
calories per week)
• Exercise does not have to be long and arduous to achieve fat loss
– The DRI definition of an “active lifestyle” requires walking for 1 hour per day
• A useful strategy is to incorporate bits of physical activity into your daily schedule
• Physical activity for weight loss or maintenance
– Moderate activities
– Large muscle groups
– Longer times in physical activity
– Adopt informal strategies to be more active
• Physical activity for building body mass
– Strength building exercises
– Balanced exercise routine
– Perform exercises with increasing intensity
– Adopt informal strategies to be more active
How the Body Loses and Gains Weight
• The balance between energy intake and energy output determines whether you gain, lose, or
maintain body fat
• A slight change in body weight may not indicate a change in body fat
– It can reflect a change in body fluid content, bone minerals, muscles, bladder or digestive tract
contents
– Change often correlates with time of day
• Weight change can be due to water gain or loss
– Most quick weight change schemes promote large changes in body fluids that accomplish little
weight change in the long run
• Smoking promotes weight loss
– Nicotine blunts feelings of hunger
– Smokers tend to weigh less than nonsmokers
– Many smokers gain weight when they stop smoking
• The down side of smoking
Cancer, chronic lung diseases, heart disease, low birthweight babies, miscarriage, shortened life
span, sudden infant death, etc.
• Moderate Weight Loss versus Rapid Weight Loss
– The normal between meal interval is 46 waking hours; 1218 hours at night
• About the length of time it takes people to use up most of the readily available fuel
• When energy input is less than energy output, the body draws on its energy stores
• With exercise, moderate calorie restriction and a balanced diet, a body will use its stores of fat
– Gradual weight loss will occur
• The Body’s Response to Fasting
– Less than 1 day into the fast: liver glycogen stores are exhausted
– Protein is broken down and converted to fat in order to meet the brain’s need for glucose
• Continued Fasting
– If left unchecked the breakdown of protein (muscle of the heart, skeletal muscle, liver, etc)
results in death within about 10 days
– To prevent this, the body converts fat into ketone bodies, a fuel the nervous system can adapt to
using
• Ketosis
– In ketosis, instead of breaking down fat to CO 2 and H 2 O, the body takes partially broken
down fat fragments and combines them to form ketone bodies
• In addition, some amino acids, those that cannot be converted to glucose, are converted
to ketone bodies
• After about 10 days of fasting, most of the nervous system’s energy needs are met by
ketone bodies
• As a result of ketosis, a healthy person starting with average body fat content can live totally
deprived of food for 6-8 weeks
• The body tolerates short term fasting
– In some animal studies, short term fasting seemed to benefit the body in some ways
– There is no evidence that fasting “cleanses” the body
• Fasting may harm the body
– Ketosis upsets the acidbase balance of the blood
• Promoting excessive mineral loss in the urine
– In as little as 24 hours of fasting, the intestinal lining begins to lose its integrity
– Food deprivation leads to overeating/ bingeing when food becomes available
• This effect may last beyond the point at which normal weight is restored
• Other effects of fasting
– Fasting degrades the body’s lean tissues; tissues are deprived of nutrients needed for vital body
components
– The body also adapts to fasting by slowing its metabolic rate
• Therefore, a diet moderately restricted in calories results in a greater weight loss and a
greater loss of fat than does a severely restricted fast
• The Body’s Response to a Low Carbohydrate Diet
– Low carbohydrate diets bring about responses similar to those seen when fasting
– As carbohydrate runs low the body breaks down fat and protein for energy and ketones form to
feed the brain
• To prevent this the DRI for carbohydrates is set at 130 grams/day; 45%65% of total
energy intake is recommended for health
• Low carbohydrate, high protein diets bring about large initial weight losses
– This large initial weight loss is primarily the water and glycogen losses that occur when
carbohydrate is lacking
• This kind of weight loss rapidly reverses when a person begins eating normally
– Loss of appetite accompanies any low calorie diet
• Weight Gain: Energy yielding nutrients contribute to excess body stores
– Protein: excess amino acids have their nitrogen removed and are used for energy or converted
to glucose or fat
– Fat: fatty acids can be broken down for energy or stored as body fat with great efficiency;
glycerol enters a pathway similar to carbohydrate
– Carbohydrate (other than fiber): excess sugars may be built up to glycogen and stored, used for
energy, or converted to fat and stored
• Alcohol: used for fuel or converted to body fat and stored
• Alcohol slows down the body’s use of fat for fuel by as much as ˜ 33%, causing more fat to be
stored
– Primarily as visceral fat
• Glycogen stores amount to ˜3/4 of a pound
• Fat stores can amount to many pounds
• Excess consumption of any food will be turned to fat within hours
• Weight gain occurs when energy input exceeds energy output
• Weight can be gained as body fat or as lean tissue, depending mostly upon whether the eater is
also exercising
Achieving and Maintaining a Healthy Body Weight
• Motivation
– Is your goal health or to achieve a societally defined idea of attractiveness?
• Goals
– Unreasonable vs. realistic goals
• Weight loss takes time and patience
• Even modest weight loss, even for a person still overweight, can improve health
What Diet Strategies Are Best for Weight Loss?
• Dietary Guidelines for Americans 2005
– Energy in must be less than energy expended
– Calorie intake must decrease to attain weight loss
– Diet based on all the food groups may be the safest and easiest in the long term
• While providing adequate essential nutrients and limiting saturated and trans fat intake
– Increase physical activity
• FDA plan to deal with the obesity epidemic
– Require food labels to prominently display calorie counts and to use meaningful serving sizes
– Launch a “Calories Count” consumer education program
– Ensure greater accuracy of food label nutrient data
– Accelerate development of obesity drugs
• Setting Goals
– For an overweight person
• First reasonable goal may be to prevent weight gain; then
• Reduce body weight by 5%10% over the course of a year
– Recognize that maintenance is often more difficult than weight loss
• Once overall goals have been set
– Set smaller goals for diet, physical activity, and behavioral changes
– Slow weight loss is less likely to result in a rapid regain of weight than is rapid weight loss
• Rapid weight loss and excessive fat restriction can cause gallstones or dangerous electrolyte
imbalances
• Keeping Records
– A tool for spotting trends and identifying areas in need of improvement
– Measure waist circumference to track changes in central obesity
• It’s Your Diet, So You’d Better Plan It
– No particular food must be included or excluded from the diet
– Adopt a healthy eating plan
• Table 9-10 : Recommendations for a Weight Loss Diet
• Choosing Realistic Calorie Intakes
– Energy intakes lower than about 800 calories (verylowcalorie diets [VLCD]) are unsuccessful
at achieving lasting weight loss, lack necessary nutrients, and may promote eating disorders
• Balancing Carbohydrates, Fats, and Protein
– Diets for weight management should provide carbohydrates, protein, fat within the DRI
recommended ranges
– High fiber, unprocessed or lightly processed foods offer bulk and satiety for fewer calories than
quickly consumed refined foods
• Choose whole grains and starchy vegetables rather than refined grains, added fats, and
sugars
– Choose fats sensibly
• Avoid saturated and trans fats
• Include enough of the health supporting fats to provide satiety but not so much as to
oversupply calories
– Protein
• Choose lean meats or other low fat protein sources
• Limit these foods but don’t eliminate them
• Alcohol
– Limit intake
– Alcohol provides abundant calories but no nutrients
– Alcohol reduces inhibitions and can sabotage a dieter’s plans
• Of Critical Importance: Portion Sizes
– The enemy is the large portions served by restaurants and sold in packages
– Train yourself to use a measuring cup to learn to judge portion sizes
– Fat grams add up quickly and contribute more calories than do grams of carbohydrate or protein
– Most people will eat more at a sitting when presented with larger portions than when provided
smaller portions
• At the end of the meal, the same sensation of fullness is reported regardless of portion
size
– Eat until satisfied
• With continued eating, satisfaction diminishes and unneeded caloric intake increases
– Eating large portions of reduced calorie foods is self defeating
– Read labels and compare calories per serving
• Using the Concept of Energy Density
– Energy density is a measure of the energy provided by a food relative to its weight
• To lower caloric intake, reduce the energy density of the diet
• Consider Milk and Milk Products
– Several studies have found that higher calcium intake, especially from lowfat milk and milk
products, correlates with lower body fatness
• Evidence suggests that calcium in milk may stimulate hormonal action that speeds up
the breakdown of stored fat
• Meal Spacing
– People who eat small, frequent meals are reported to be more successful at weight loss and
management
– Make sure that mild hunger, not appetite, prompts eating
– Eat regularly, before becoming extremely hungry
– Eat the entire meal you have planned for yourself
• Then don’t eat again until the next meal or snack
– Save calorie free or favorite foods or beverages for a planned snack at the end of the day if you
need insurance against late evening hunger
– Eat breakfast
• Eating breakfast may reduce food intake all day long
• People who skip breakfast are more likely to be overweight
– Those who consume the majority of their calories after 6:00 p.m. often find it harder to lose
weight than people who eat earlier in the day
• ˜30-60 minutes of moderate physical activity per day are needed to prevent weight gain and
support weight loss
– Diet, in combination with exercise, promotes fat loss, promotes muscle retention, inhibits
weight gain
– Exercise helps people follow diet plans more closely
• Exercise reduces abdominal obesity
– Improves BP, insulin resistance, heart and lung fitness
• Even without weight loss
• Increasing Metabolism and Reducing Appetite
– Short term increase in energy expenditure
• From exercise and a slight rise in metabolism
– Long term increase in BMR
• From an increase in lean tissue
– Improved body composition
• More physical activity benefits
– Appetite control
– Stress reduction and control of stress eating
– Physical, and therefore psychological, well being
– Improved self esteem
• Choosing Activities
– Any activity is better than no activity
– Expenditure of al least 2,000 calories per week in physical activity promotes weight
management
Perform an activity at a comfortable pace
• Rushing is a great way to get injured
– Engage in activities of low to moderate intensity for a long duration
• Easier to stick with
• Less likely to result in an injury
– If at a higher fitness level
• Higher intensity activities may be performed for shorter periods of time
– Increase daily energy expenditure by, for example,
• Taking the stairs rather than the elevator
• Walking/biking rather than driving
• Spot Reducing
– Exercise cannot remove fat from any one particular area
– Exercise
• Aerobic activity promotes the release of abdominal fat
• Improves the strength and tone of muscle in problem areas
What Strategies are Best for Weight Gain?
• An underweight person should not necessarily try to gain weight
– If you are healthy, maintain your current weight
• Examples of those who may be at health risk from a too low body weight
– Physician has advised you to gain weight
– You are excessively tired
– You are unable to keep warm
– You fall into the underweight category of the BMI
– You are a woman who has missed at least three consecutive menstrual periods
• Physical Activity to Gain Muscle and Fat
– Best achieved through physical activity
• Especially strength training in combination with a high calorie diet
– Diet alone can bring about weight gain in the form of fat
• Which, for someone with a wasting disease, would be a good idea
• If you eat enough to support the activity, you will gain muscle at the expense of body fat
• If you eat more, you will gain both muscle and fat
• Gaining a pound of muscle and fat requires an intake of ˜3,000 extra calories
• People wanting to build muscle are advised to eat ˜7001,000 calories/day above normal energy
needs
• Choose Foods with High Energy Density
– Chose nutritious energy dense foods, for example
• Peanut butter in place of lean meat
• Avocado in place of cucumber
• Portion Size and Meal Spacing
– Increase portion sizes
• Large plates, bowls, and glasses
– Expect to feel full
• Feeling passes as stomach adapts to the extra food
– Eat frequently
– Make foods appealing
• Variety and palatability
• Start with the main course
• Drink between meals, not with meals
• Always eat dessert
• Weight Gain Supplements
– Most “weight gain” supplements are useless without physical activity
• Confer no benefits beyond adding calories and a few nutrients
• Items such as instant breakfast powders or milk flavorings can do the same thing for
less money
– Of the weight gained in a day, only 0.5-1 ounce is protein tissue
• Protein supplements cannot speed up weight gain
• Avoid Tobacco
– Suppresses appetite
– Makes taste buds less sensitive
Drugs and Surgery to Treat Obesity
• BMI=30 and those with elevated disease risk may benefit from prescription medication, along
with diet, exercise, and behavior therapy, to lose weight
• Extreme obesity (BMI=40; BMI=35 with coexisting disease); a.k.a. morbid obesity
– Health permitting, surgery may be an option
• Surgical reduction of stomach size
• Surgery is not a cure for obesity
– Some do not lose the expected pounds
– Some who initially lose weight gain it back through the course of time
• Long term safety and effectiveness of gastric surgery primarily depends on compliance with
dietary instructions
• Complications immediately following surgery include
Infections, nausea, vomiting, dehydration
• Longterm complications include
– Vitamin and mineral deficiencies
– Psychological problems
– Such surgery requires lifelong medical supervision
• Lipectomy (liposuction)
– Cosmetic procedure
– If fat is gained back after surgery, as it often is, a lumpy, dimpled layer can be formed
– There can be serious complications, including death, as a result of the surgery
• Herbal Products
– For many, their effectiveness and safety have not been proved
– “Natural” does not mean safe
• Belladonna, hemlock, and sassafras all contain toxins
– Marketed as “dietary supplements” and thus escape FDA scrutiny
• Ephedra (ma huang) contains ephedrine
– Preliminary studies showed that it promotes weight loss
– Side effects
Cardiac arrest, abnormal heart beat, hypertension, stroke, seizure, death,
– FDA has banned sales
• TRIAC
– Sold as diet aid
– Hormone that interferes with thyroid function
– Has caused heart attack and stroke
• Herbal laxatives containing senna, aloe, rhubarb root, cascara, castor oil, or buckthorn
– Sold as “dieter’s tea”
– Can cause temporary water loss of 12 pounds
– Side effects include: nausea, vomiting, diarrhea, cramping, fainting
– Suspect in 4 deaths
• Other Gimmicks
– Steam baths and saunas do not melt off fat
• May dehydrate you and result in water loss
– Brushes, sponges, wraps, creams, and massages intended to move, burn, or break up “cellulite”
are useless for fat loss
• Cellulite - rumpled, dimpled fat tissue on thighs and buttocks is simply fat
• FDA has sent letters warning supplement distributors to stop claiming that their products:
– Block starch, fat, sugar absorption
– Neutralize starch, fat, or sugar in a meal
– Promote weight loss with no effort
Controversy: The Perils of Eating Disorders
• ˜5 million people in the U.S. suffer from eating disorders
– Mainly females
– Anorexia nervosa
– Bulimia nervosa
– Many more suffer from binge eating disorder
• ˜85% of eating disorders start during adolescence
– Markers of disordered eating including restrained eating, binge eating, purging, fear of fatness,
distorted body image are common
• Causes of eating disorders
– Excessive pressure to be thin is at least partly to blame
• When low body weight becomes an important goal, people begin to view normal,
healthy body weight as too fat
– Painful emotions may be turned inward by youngsters to express dissatisfaction with body
weight or say they “feel fat”
• As weight loss and diet restraint become more of a focus, psychological problems
worsen, and the likelihood of developing eating disorders increases
• Eating Disorders in Athletes
– Athletes and dancers are at special risk of eating disorders
– Female athlete triad
• Disordered eating
• Amenorrhea
• Osteoporosis
– Males: disordered eating brings on many of the same physical problems affecting female
counterparts
• The Female Athlete Triad
– Female athletes often (are encouraged to) compare themselves to unsuitable weight standards
– An ultraslim appearance has long been considered desirable in activities such as dancing,
gymnastics, and figure skating
• The problem is that these activities require more weight for a given height than a
nonathlete’s body because of the greater need for muscle, dense bone, and less fat
• Amenorrhea
– Not an adaptation to strenuous physical training
– Symptom that something is wrong
– Is particularly hazardous to the bones
• Weightbearing exercise usually increases bone mass; however, for the anorexic
strenuous activity can imperil their bones even after recovery from the eating disorder
• Male Athletes and Eating Disorders
– Male athletes and dancers who face pressure to achieve a certain body weight may develop
eating disorders
– They may deny having them in the mistaken belief that the disorders strike only women
• Practices such as those engaged in by wrestlers trying to “make weight” can compromise
athletic abilities and endanger their lives
– Such practices result in diminished anaerobic strength, reduced endurance, decreased oxygen
capacity, and general weakness caused by food deprivation and dehydration, an effect lasting
days after food and water are replenished
• Male athletes are susceptible to weight gain problems
– Athletes with well muscled bodies see themselves as underweight and weak
• Such distorted body image leads to frequent weighing, excessive exercise, overuse of
special diets or protein supplements, or even abuse of steroid drugs
• Characteristics of Anorexia Nervosa
– Most anorexia nervosa victims come from middle or upper-class families
– Males account for ˜ 5% to 10% of cases in the general population
• The incidence among male athletes and dancers may be much higher
• No one knows what causes anorexia nervosa
– Central to its diagnosis is a distorted body image that overestimates body fatness
• The more body sizes are overestimated the greater the resistance to treatment
• Malnutrition is known to affect brain functioning and judgment in this way
• Anorexia Nervosa : The Role of the Family
– Family, especially parental, attitudes contribute to eating disorders
– Families of anorexics are likely to be critical and to overvalue outward appearances while
undervaluing inner self worth
of Eating Disorders
• Parents may oppose one another’s authority
• In the extreme, parents may be sexually or otherwise abusive
• Anorexics may be perfectionists
– Identifying so strongly with parents’ ideals and goals that they cannot get in touch with their
own identity
– Respectful of authority: polite, controlled, rigid, unspontaneous
– Rejecting food is a way of gaining control
• Anorexia Nervosa : Self Starvation
– Discipline is used to strictly limit portions of low calorie foods
– Hunger is denied
– Becoming accustomed to little food one can feel full after eating as little as a half-dozen carrot
sticks
– Calorie contents of foods are memorized
– Calorie costs of exercises are memorized
• If she thinks she has gained an ounce of weight, exercise ensues until she thinks she has lost the
weight
• She drinks water incessantly to fill her stomach
– Risking dangerous mineral balances
• If she feels that energy intake has exceeded energy output, she takes laxatives to promote the
passage of food from her system
– Not knowing that laxatives reduce water absorption, but not food energy absorption
• She is starving, but doesn’t eat because of her need for self control
• Anorexia Nervosa : Physical Perils
– Brings the same damage as classic protein-energy malnutrition
– Body tissues are depleted of needed fat and protein
– In young people, growth ceases and normal development falters
• So much lean tissue is lost that BMR slows
• In athletes
– The loss of lean tissue impairs performance
• The heart pumps inefficiently and irregularly
• Heart muscle becomes weak and thin
• Blood pressure falls
• Electrolytes that help to regulate heart beat go out of balance
• Many deaths are due to heart failure
• The brain loses significant amounts of tissue
• Nerves function abnormally
• Electrical activity of the brain becomes abnormal
• Insomnia is common
• Digestive functioning becomes sluggish
• The stomach empties slowly
• The lining of the intestinal tract shrinks
• The digestive tract fails to digest food adequately, even if the victim eats
• Pancreatic production of digestive enzymes slows
• Diarrhea
• Anemia
• Impaired immune response
• Altered blood lipids
• High blood concentrations of vitamins A and E
• Low blood proteins
• Dry skin
• Low body temperature
• The development of fine body hair
• In adults, both women and men lose their sex drives
• Mothers with anorexia nervosa may severely underfeed their children
– The children then fail to grow and suffer the other harms typical of starvation
• Treatment of Anorexia Nervosa
– Requires a multidisciplinary approach
• Approaches relating to food and weight
– Appropriate diet is crucial for normalizing weight
• Approaches concerned with relationships with oneself and others
• Clients are classified based on the risk posed by the degree of malnutrition
• Low risk clients may benefit from
– Family counseling
– Cognitive therapy
– Behavior modification
– Nutrition guidance
• High risk clients may also need
– Other forms of psychotherapy
– Supplemental formulas to provide energy and nutrients
– Drugs are commonly prescribed, but their usefulness is limited
• Treatment goals
– Stopping weight loss is the first goal
– Establishing regular eating patterns is the next goal
– Progress will be slow at first due to an increase in metabolic rate and an increase in thermic
response to food
– With small gains of fat, leptin concentrations will increase
• Few anorexics seek treatment on their own
• Denial makes treatment difficult
• Many relapse into abnormal eating behaviors
• Anorexia nervosa has one of the highest mortality rates among psychiatric disorders
• Characteristics of Bulimia Nervosa
– Much more prevalent then anorexia nervosa
• True incidence is difficult to establish
• People often suffer in secret and may deny the existence of a problem
– More men suffer from bulimia nervosa than from anorexia nervosa
• However, bulimia nervosa is still most common in women
• Bulimia Nervosa: The Role of the Family
– Externally controlling, but emotionally uninvolved with their children, resulting in a stifling
negative self image
• Common in the families of people with bulimia
Dieting, Arguments, Criticism of body shape or weight, minimal affection and caring, other
weaknesses, hidden family “secrets”
• Bulimic women who report sexual or physical abuse by family members or friends may
continually suffer a sense of being unable to gain control
• Family cooperation is key
– Should the person with bulimia begin to make changes toward recovery, others in the family
may feel threatened
– Family cooperation is important in recovery
• Bulimia Nervosa: Binge Eating and Purging
– Food is not consumed for its nutritional value
– During a binge, eating is accelerated by hunger from previous caloric restriction
– During a binge, nearly 1,000 extra calories are consumed
– There may be several binges in a day
• Typical binge foods
– Easy-to-eat foods
– Low-fiber
– Smooth-texture
– High-fat
– High-carbohydrate
• The binge is a compulsion and usually occurs in several stages
Anticipation and planning, anxiety, urgency to begin, rapid and uncontrollable consumption of
food, relief and relaxation, disappointment, shame or disgust
• After a binge, to purge the food a cathartic or emetic may be used
• After the binge
– Hands may be scraped raw against the teeth during induced vomiting
– Swollen neck glands and reddened eyes from straining to vomit
– Bloating, fatigue, headache, nausea, pain
• Bulimia Nervosa: Physical and Psychological Perils
– Fluid and electrolyte imbalances caused by vomiting or diarrhea
• Abnormal heart rhythms and injury to the kidneys
– UTI’s can lead to kidney failure
• Vomiting causes
– Irritation and infection of the pharynx, esophagus, salivary glands
– Erosion of the teeth and dental caries
– The esophagus or stomach may rupture or tear
– Overuse of emetics can lead to death by heart failure
• Unlike anorexics, bulimics are aware that their behavior is abnormal, and they are ashamed of it
• Bulimics are less less likely to be in denial and more likely to recover
• Treatment of Bulimia Nervosa
– To regain control over food and establish regular eating patterns requires adherence to a
structured eating plan
– Regular exercise may be of benefit
– Restrictive dieting is forbidden
• Almost always precedes and may trigger binges
• Goals
– Steady maintenance of weight
– Prevention of relapse into cyclic gains and losses
• Learning to consistently eat enough food to satisfy hunger needs is a major step towards
recovery
• ˜50% of females diagnosed with bulimia recover completely after 5-10 years with or without
treatment
– Treatment probably speeds the recovery
• Antidepressant medication may be of benefit
• Anorexia nervosa and bulimia nervosa sometimes overlap
– People with these disorders share an over-concern with body weight and the tendency to
drastically overeat
– People with either disorder may purge
– Both disorders can appear in the same person, or one can lead to the other
– Some people have eating disorders that fall short of either disorder, but share some of their
features
• Binge Eating Disorder
– Up to 50% of all people who restrict eating to lose weight periodically binge without purging
• Including about 1/3 of obese people who regularly engage in binge eating
– Obesity itself does not constitute an eating disorder
• People with binge eating disorder consume less during a binge, rarely purge, and exert less
restraint during times of dieting than those with bulimia nervosa
• Like those with bulimia nervosa those with binge eating disorder have feelings of being out of
control, disgust, depression, embarrassment, guilt, or distress because of self-perceived gluttony
• Binge eating behavior responds more readily to treatment than other disorders
• Successful treatment improves physical health, mental health, and the chances of breaking the
cycle of rapid weight losses and gains
• Eating Disorders in Society
– Eating disorders have many causes
• Sociocultural
– Known only in developed nations
– Become more prevalent as wealth increases and food becomes plentiful
• Psychological
• Heredity
• Probably neurochemical
• Society sets unrealistic ideals for body
weight
– Especially for women
– There is a devaluation of women who do not conform to these ideals
– Miss America winners have become thinner over the years
• The best defense
– Learn about normal, expected, growth patterns
• Especially the characteristic weight gain of adolescents
– Learn respect for the inherent wisdom of the body
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