chapter 9 nutr

© 2009 Cengage - Wadsworth

Chapter 9

Weight Management: Overweight, Obesity, and

Underweight


Overweight

• Overweight (BMI 25-29.9) and obesity (≥ 30) are widespread health problems that are continuing to increase.

• Many refer to overweight and obesity as an epidemic.

• For good health, weight management is important.


Overweight

• Fat Cell DevelopmentFat cell numbers

• Fat cell numbers increase most rapidly in later childhood and early puberty.

• Fat cell numbers increase in times of positive energy balance.

• Hyperplastic obesity


Overweight

• Fat Cell DevelopmentFat cell size

• Fat cell sizes increase when energy intake exceeds expenditure.

• Hypertrophic obesity

The adverse effects of fat in non-adipose tissue are called lipotoxicity.


Overweight

• Fat Cell MetabolismLipoprotein lipase promotes fat

storage.Gender differences

• Men are at increased risk for developing central obesity and women are at increased risk for lower body fat.

• Enzymes that break down fats affect men and women differently.


Overweight

• Set-Point TheoryThe body’s natural regulatory centers

maintain homeostasis at set point.The human body tends to maintain a

certain weight.


Causes of Obesity

• Obesity may not be as simple as food intake exceeding metabolic needs.

• Some factors, such as overeating and inactivity, are within our control.

• Genetic, hormonal and emotional factors may require professional intervention.


Causes of Obesity

• Genetics Leptin (also called the ob protein)

• Protein that acts as a hormone to increase energy expenditure and decrease appetite

• Produced by fat cells under the direction of the ob gene

• May be deficient in obese individuals• More research is needed.


Causes of Obesity

• GeneticsGhrelin

• Protein that acts as a hormone to decrease energy expenditure and increase appetite

• Produced by stomach cells • Has an inverse relationship with PYY


Causes of Obesity

• GeneticsUncoupling Proteins

• Influence energy metabolism• White adipose tissue stores fat to be used

for energy.• Brown adipose tissue stores fat to be

used for heat.• May oppose the development of obesity


Causes of Obesity

• Environment – The gene pool of our population remains relatively unchanged.Overeating

• Present and past eating influences current body weight.

• Increased availability of convenient food, large portions, and energy-dense foods

Physical Inactivity• Modern technology replaces physical activities.• Physical activity is important to allow people to

eat enough food to get needed nutrients.


Problems with Obesity

• Obesity problems depend on many factors such as the extent of overweight, age, health status and genetic makeup.

• Risk factors may differ among individuals.



• Health risks are evaluated using BMI, waist circumference and disease profiles. Overweight people who are in good health may not

need to lose weight. Obese or overweight people with risk factors could

improve health by losing weight or using other diet and exercise strategies. Risk factors include:

• Hypertension• Cigarette smoking• High LDL• Low HDL• Impaired glucose tolerance• Family history of heart disease• Men ≥ 45 years, women ≥ 55 years



• Health RisksObese or overweight people with the

following life-threatening-conditions may improve health by losing weight:• Heart disease• Type 2 diabetes• Sleep apnea



• Perceptions and PrejudicesSocial Consequences

• Prejudices and discrimination• Judged on appearance rather than character• Stereotyped as lazy and lacking self-control

Psychological Problems• Feelings of rejection, shame and depression are

common.• Ineffective treatments can lead to a sense of

failure.



• Dangerous InterventionsFad Diets

• False theories• Inadequate diets• Can be a danger to health



• Dangerous InterventionsWeight-Loss Products

• Ephedrine-containing products inhibit serotonin and suppress the appetite. Supplements containing Ephedra have been banned by the FDA due to potential health risks.

• Herbal laxatives do not prevent absorption.• Current laws do not require safety tests and

effectiveness tests for these products.

Other Gimmicks• Don’t work• There is no such thing as cellulite.


Aggressive Treatments of Obesity

• Individuals with clinically severe obesity and major medical problems may benefit from drugs or bariatric surgery.

• But changing and improving eating and exercise habits offer the greatest benefit.



• DrugsSibutramine suppresses the appetite

and is most effective when used with a reduced kcalorie diet and increased physical activity. There are many side effects.

Orlistat blocks fat digestion and absorption. There are many side effects.

Other drugs are still under study.



• SurgerySurgery is an option for those who have

tried weight loss programs and failed, have a BMI ≥ 35, and are having health problems due to their weight.

Gastric surgery has short-term and long-term problems and requires compliance with dietary instructions.

Liposuction is a popular procedure that is primarily cosmetic but poses risk.


Weight-Loss Strategies

• A life-long eating plan for good health, which includes nutritionally adequate eating, reasonable expectations, regular physical activity, and permanent lifestyle changes, is best for achieving permanent weight loss.

• Weight loss of 1-2 pounds per week or 10% of body weight in six months is safe.



• Eating PlansBe Realistic about Energy Intake

• 300-500 kcalories/day reduction for BMI between 27 and 35

• 500-1000 kcalories/day reduction for BMI ≥ 35• Dietary Guidelines should be followed.

Diet should be nutritionally adequate while avoiding excessive consumption.

Smaller portions are recommended to feel satisfied, not stuffed.



• Eating PlansEat foods of lower energy density, that are

high in fiber, high in water and low in fat.Water is important to increase fullness and

reduce hunger.Complex carbohydrates offer abundant

vitamins, minerals and fiber with little fat.Choose fats sensibly and reduce the

quantity of fat.Watch empty kcalories from sugar and

alcohol.



• Physical Activity An individual’s body weight as well as intensity and

duration of activity influence energy expenditure. Physical activity increases the amount of

discretionary kcalories that can be consumed. Metabolic rates can rise with daily vigorous activity. Activity can decrease body fat and increase lean

body mass. Exercise may help to curb appetite.

Activity can reduce stress and improve self-esteem.



• Physical ActivityChoosing Activities

• Choose activities that you enjoy and are willing to do regularly.

• Low to moderate intensity for long duration is recommended.

• Daily routines can incorporate energy activities.Spot Reducing

• Regular aerobic exercise and weight loss will help trouble spots.

• Strength training can improve muscle tone.• Stretching can help flexibility.



• Behavior and AttitudeBehavior modification requires time and

effort.Awareness of behavior is the first key.Changing behaviors one at a time works best.

• Do not grocery shop when hungry.• Eat slowly.• Exercise while watching television.

Personal attitudes toward food and eating must be understood.

Support groups may be helpful for some people.



• Weight MaintenanceSuccessful weight-loss maintenance

programs use different criteria so they are difficult to compare.

Vigorous exercise and careful eating plans are key.

Frequent self-monitoring is recommended.



• PreventionEat regular meals and limit snacking.Drink water in place of high-kcalorie

beverages.Select sensible portion sizes and limit

daily energy intake to energy expended.

Limit sedentary activities and be physically active.



• Public health programs have been suggested to:Develop safety standards for foods.Control commercial advertising.Control conditions under which foods

are sold.Control prices to reduce consumption.


Underweight

• Incidences of underweight and associated health problems are less prevalent than overweight and obesity problems.


Underweight

• Problems of UnderweightCauses are diverse.Energy demands may be great and

foods are needed to support growth and physical activities.

Eating disorders are severe cases.


Underweight

• Weight-Gain StrategiesEnergy-dense foods can be included but

choose fat wisely to avoid the associated cardiac risks.

Regular meals each day must become a priority.

Use large portions and expect to feel full.Consume extra snacks between meals. Juice and milk are easy ways to increase

kcalories.Exercising to build muscles will support

increases in muscle mass.


The Latest and Greatest Weight-Loss Diet--Again


The Latest and Greatest Weight-Loss Diet--Again

• Fad diets do not offer safe or effective plans for weight loss.

• Diet recommendations should be research based.

• There are guidelines for identifying fad diets and weight-loss scams.


The Diet’s Appeal

• There are many misconceptions and distortions of facts.

• Results are not long lasting.


The Diet’s Achievements

• Don’t Count kCalories • Satisfy Hunger• Follow a Plan• Limit Choices


The Diet’s Shortcomings

• Too Much Fat• Too Much Protein• Too Little of Everything Else


The Body’s Perspective

• Adverse side effects of low-carbohydrate, ketogenic dietsNauseaFatigueConstipationLow blood pressureElevated uric acidStale, foul taste in the mouthFetal harm and stillbirth

chapter 9 nutr

Health & Medicine

cengage wadsworth

obesity obesity problems

developingcentral obesity

obesity perceptions

obesity environment

obesity geneticsleptin

hyperplastic obesity

development of obesity