Chapter 9 Energy Balance and Weight Management

Chapter 9 Energy Balance and Weight Management

A Closer Look at Obesity
Bodies come in many shapes and sizes. Which are healthy? © 2007 Thomson - Wadsworth

In the US 66% of adults are overweight or obese. The trend increase over the time. F I G U R E 9 – 1: TRENDS IN PREVALENCE OF OVERWEIGHT AND OBESITY AMONG CHILDREN AND ADULTS,UNITED STATES, 1988 TO 2002 © 2007 Thomson - Wadsworth

Note the increasingly upward trend of obesity among the 50 states 1991 – no states had obesity rate > 40%, only 4 states > 15% 2000 – only Colorado was < 15%, 22 states > 20% 2004 – 7 states 15-19%, 33 states 20-24%, 9 states > 25% © 2007 Thomson - Wadsworth

Obesity affect both men and women Obesity affect all racial and ethnical groups Obesity rates for minorities often exceed those in the general population Among African- Americans 34% men 54% women Mexican Americans 32% men 42% women Copyright 2010, John Wiley & Sons, Inc.

Weight Management Terms
Energy balance occurs when energy consumed equals energy expenditure. Energy is measured in kilocalories (kcal, kcalories) or kilojoules (kjoules, kJ). A kcalorie is a measure of the amount of energy that is supplied to or expended by the body. Overweight is being too heavy for one’s height or having a BMI of 25–29. Obesity is characterized by excess body fat or a BMI over 30. Copyright 2010, John Wiley & Sons, Inc. 6

Factors affects to obesity: Genetics Environmental Factors: Nutrition Energy intake Food portion size Availability of energy-dense foods Physical activity Sedentary lifestyles v Socio-economic Built environment that fails to facilitate fitness © 2007 Thomson - Wadsworth

Food portion sizes and obesity rates have grown in parallel. Vending machines selling soft drinks, high-fat snacks, and sweet snacks are common in schools and workplaces. Adults spend more time in sedentary activities, such as watching television or commuting to and from work and school. Children watch 12 to 14 hours of television a week and spend 7 hours playing video games. Schools offer fewer physical education classes for children. Increasing numbers of families live in communities designed for car use, unsuitable and often unsafe for activities such as walking, biking, and running. © 2007 Thomson - Wadsworth

Problems Associated with Weight
Overweight and obesity: Increases risks of hypertension Increases risks for Heart disease Increases diabetes in those who are genetically predisposed Increases risks for Gallbladder disease (susceptible people) Increase risk for breast cancer Increase risk of uterus prostate and colon cancer Maternal overweight increases risk for neural tube defects in their offspring © 2007 Thomson - Wadsworth

Increase incidence of and severity of infectious disease Poor wound healing Surgical complications The longer carry excess fat, the greater the risks, individuals who gain excess weight at a young age and remain overweight through life face the greater health risk Copyright 2010, John Wiley & Sons, Inc.

Obesity is seen as a social and economic handicap in some parts of North America. Most likely to experience depression, negative self-image and feeling of in-adequacy Obese individuals suffer discrimination in many areas, which can harm them psychologically. College, transportation, … © 2007 Thomson - Wadsworth

Fact: Obesity rates are higher than ever. 65% of adults 16% of children and adolescents in the U.S. are either overweight Annual cost of overweight and obesity More than $117 billion a year. Direct costs (treatment) : $61 billion Indirect costs (lost productivity, disability, morbidity & mortality): $56 billion © 2007 Thomson - Wadsworth

Consequences of Excess Body Fat
Copyright 2010, John Wiley & Sons, Inc. 16

What is the Healthy Weight?

Overweight: Weight between: 10% and 20% above the desirable weight for height Body mass index (BMI): Obesity: Weight 20% or more above the desirable weight for height BMI of 30 or greater. Overweight Conventionally defined © 2007 Thomson - Wadsworth

A healthy weight is a weight that minimizes health risks. Body weight: Fat + Lean body mass Weight and fat : Age, sex, gender, lifestyle and the location of the fat Copyright 2010, John Wiley & Sons, Inc.

Copyright 2010, John Wiley & Sons, Inc.
BMI A measure of body weight relative to height that is used to compare body size with standard BMI is not measure of the body fat, it is recommended as a way to assess body fatness that is better than measuring weight alone Copyright 2010, John Wiley & Sons, Inc.

Understanding BMI Cautions in Using BMI:
May overestimate body fat in athletes and underestimate body fat in adults over 65. A muscular person, such as this body builder, often has a low percentage of body fat but a high BMI. © 2007 Thomson - Wadsworth

Healthful Weight? Body Weight versus Body Fat
Two people of the same sex, age, and height may both weigh the same, yet one may be too fat and the other too thin. Here are some ways that is possible: The difference lies in their body composition. One may have small, light bones and minimally developed muscles, while the other has big, heavy bones and well-developed muscles. The health risks for obesity refer to people who are over fat. © 2007 Thomson - Wadsworth

Healthful Weight? How obesity must be defined?
By amount of body fat rather than body weight. The health risk of obesity refer to people: Men having 25 percent body fat Women having 33 percent body fat Desirable measures for percent body fat: Men 8-19% (over fat would be >25%) Women 21-32% (over fat would be >33%) We can change by exercise. Body fat can measure with different techniques. © 2007 Thomson - Wadsworth

Measuring Body Composition

Measuring Body Density
Underwater weighing (hydrostatic weighing) This method measures whole body density by determining body volume. There is a variety of equipment available to do underwater weighing ranging in sophistication from the standard stainless steel tank with a chair or cot mounted on underwater scales, to a chair and scale suspended from a diving board over a pool or hot tub.

Underwater weighing: First weigh a person outside the tank, then immersing them totally in water and weighing them again. The densities of bone and muscles are higher than water, and fat is less dense than water. So a person with more bone and muscle will weight more in water than a person with less bone and muscle, meaning they have a higher body density and lower percentage of body fat. From body density using standard equations. Lean tissue is dense than fat tissue The volume of the body is calculated and the individual's body density is determined by using standard formulas. Then body fat percentage is calculated Accurate but can not be use for children.

BOD POD (Air Displacement) - Based on the same principle as underwater weighing, the BOD POD used computerized sensors to measure how much air is displaced while a person sits for 20 seconds in a capsule. It uses a calculation to determine body density, then estimated body fat. The equipment is very expensive and limited in availability. © 2007 Thomson - Wadsworth

Measuring Body Fat Skinfold test: Using a caliper to measure the thickness of a fold of fat, the measurement is then applied to a standard table to give a fair approximation of total body fat. Inexpensive, fast. easy, not accurate © 2007 Thomson - Wadsworth

Healthful Weight? Measuring Body Fat
Dual energy X-ray absorptiometry (the DEXA test) can yield an accurate image of the body’s fat-free tissue and total fat content. © 2007 Thomson - Wadsworth

A relatively new technology that is very accurate and precise DEXA is based on a three-compartment model that divides the body into total body mineral, fat-free soft (lean) mass, and fat tissue mass. This technique is based on the assumption that bone mineral content is directly proportional to the amount of photon energy absorbed by the bone being studied. DEXA uses a whole body scanner that has two low dose x-rays at different sources that read bone and soft tissue mass simultaneously. © parisa.assassi

Healthful Weight? Measuring Body Fat
Bioelectrical impedance: estimation of body fat content made by measuring how quickly electrical current is conducted through the body. It provides a measure of how much fat a person has by measuring the speed at which a slight electrical current is conducted through the body (from the ankle to the wrist). © 2007 Thomson - Wadsworth

Body Fat Distribution Patterns
Distribution of Fat Central obesity: excess fat on the abdomen and around the trunk (visceral fat) “Apple-shaped” body Strong risk factor for type 2 diabetes, heart disease, hypertension, and other problems. Peripheral obesity: excess fat on the arms, thighs, hips, and buttocks (subcutaneous fat). © 2007 Thomson - Wadsworth

Healthful Weight? Excess abdominal fat poses a greater health risk than excess fat in the hips and thighs, The extra abdominal fat crowds the organs and its proximity to liver means that , when metabolized , abdominal fat can raise blood cholesterol and lower the body’s sensitive to insulin. © parisa.assassi

Body Weight and Health Weighing for Health
A person’s health risk is dependent on three factors: Body weight Amount and location of body fat Current health status Body mass index: an index of a person’s weight in relation to height that correlates with total body fat content. Keep in mind that BMI does not account for: Location of fat in the body Fact that a muscular person with a low percentage of body fat may have a high BMI

Cause of Obesity Factors affects to obesity: Genetics
Environmental Factors: Nutrition Energy intake Food portion size Availability of energy-dense foods Physical activity Sedentary lifestyles Socio-economic Busy schedules (fast food) Built environment that fails to facilitate fitness Fast foods are typically higher in fat and energy than foods prepared at home.. © 2007 Thomson - Wadsworth

Causes of Obesity A Closer Look at Eating Behavior
Hunger: the physiological drive to find and eat food, experienced as an unpleasant sensation. Appetite: the psychological desire to find and eat food, experienced as a pleasant sensation, often in the absence of hunger. Satiety: the feeling of fullness or satisfaction that people feel following a meal. © 2007 Thomson - Wadsworth

Causes of Obesity UNDER- ACTIVITY
The most important single contributor to the obesity problem in our country UNDER- ACTIVITY Job, Drive Leisure time After school program diettired.com

Energy Balance You store extra energy as fat You lose stored fat
if you eat more food energy in a day than you expend (daily activity,…) You lose stored fat if you eat less food energy in a day than you expend. For each 3,500 calories you eat in excess of need, you store 1 pound of body fat. Change in energy stores = Energy in - Energy out © 2007 Thomson - Wadsworth

Energy Balance The body expends most of its energy on basal metabolism—maintaining basic physiological processes such as breathing, heartbeat, and other involuntary activities. The second largest amount of energy is expended for voluntary physical activities—an amount that will vary by activity level. A minor amount of energy is also used for the thermic effect of food— the energy needed to digest, absorb, and process the food you eat. Total energy expenditure 60-75% basal metabolism Activity Thermogenesis has two constituents, exercise-related activity thermogenesis and Non-exercise Activity Thermogenesis (NEAT). For the vast majority of dwellers in the U.S., exercise activity thermogenesis is negligible. NEAT, even in avid exercisers, is the predominant constituent of activity thermogenesis and is the EE associated with all the activities we undertake as vibrant, independent beings. NEAT has an enormous variety of constituents including occupation, leisure and fidgeting. Because of this, NEAT is challenging to study and its role in human energy balance has been difficult to define. HOW THE BODY EXPENDS ENERGY © 2007 Thomson - Wadsworth

Energy Balance Basal metabolism:
The sum total of all the chemical activities of the cells necessary to sustain life, exclusive of voluntary activities—that is, the ongoing activities of the cells when the body is at rest. Basal metabolic rate (BMR): The rate at which the body spends energy to support its basal metabolism. The BMR accounts for the largest component of a person’s daily energy (calorie) needs. © 2007 Thomson - Wadsworth

Energy Balance If you increase your physical activity consistently
you will also increase the energy your body spends on metabolic activity because you will have an increase in lean body mass. The energy spent on physical activity is the energy spent moving the body’s skeletal muscles, and the extra energy spent to speed up the heartbeat and respiration rate as needed. The number of calories spent depends on 3 factors: The amount of muscle mass required The amount of weight being moved The amount of time the activity takes © 2007 Thomson - Wadsworth

Weight Gain and Loss FEASTING AND FASTING: In A, the person is storing energy. When you eat more calories then you need, the energy nutrients contribute to body stores. 2. Carbohydrate is broken down to glucose for absorption. a. Inside the body, glucose may be built up to glycogen or converted to fat and stored as such. 3. Fat is broken down to its components for absorption. a. Inside the body, these components are converted to fat storage. 4. Protein is broken down to its basic units (amino acids) for absorption. a. Inside the body, these units may be used to replace body proteins. b. Those amino acids that are not used cannot be stored as protein for later; they lose their nitrogen and are converted to fat. 5. Although 3 kinds of materials enter the body, they are stored for later use in only 2 forms: glycogen and fat. Of the 3 energy nutrients, fat from food is especially easy for the body to store as fat tissue. 7. If you choose to overeat, there may be some advantage to overeating carbohydrate-rich foods such as vegetables or legumes rather than overeating fat-rich butter or sour cream - you may deposit less fat. © 2007 Thomson - Wadsworth

Weight Gain and Loss If a person doesn’t eat for a long period of time, the body makes one adjustment after another. The first adjustment is to use the liver’s glycogen. Another alternative source of energy would be the abundant fat stores most people carry. This fuel is no use to the nervous system because while the muscles and other organs use fat as fuel, the nervous system only possess enzymes to convert protein to glucose. As the fast continues, the body turns to its own lean tissues to keep up the supply of glucose. © 2007 Thomson - Wadsworth

Physical Activity Level and PA Value

EER Prediction Equations

Contributing Factors for Obesity
Genetics The theory that a hereditary, inside-the-body basis for obesity may exist is supported by the existence of animal strains that are genetically fat. In humans, studies have shown that identical twins, whether raised together or apart, tend to have similar weight-gain patterns (among 75%). 25% environmental factors © 2007 Thomson - Wadsworth

People may overeat or under-exercise because they are pushed to do so by factors in their surroundings. Some people may have inherited or learned a way of resisting external stimuli to eat, while others have not. A study found a positive correlation between over-fatness and a diet offering a wide variety of snacks and sweets. © 2007 Thomson - Wadsworth

Set-point theory: Some researchers suggest that the body “wants” to maintain a certain amount of fat and regular eating behaviors and hormonal actions to defend its “set-point.” The theory implies that science should search inside obese people to find the causes of the problems, perhaps in their hunger-regulating mechanism. © 2007 Thomson - Wadsworth

Leptin Researchers have identified a gene named ob (for obese) that appears to produce a hormone called leptin (Greek word for slender). Leptin seems to tell the body to stop eating when it is released from fat cells. As body fat stores increase, blood leptin increases; likewise, when body fat stores decrease, blood leptin decreases, and the brain responds by stimulating appetite and decreasing energy expenditure. Overweight people may have a defective form of this gene (or may be unresponsive to its hormone), which fails to give an accurate report of the size of the fat cells to the brain, thus making the set-point too high and resulting in weight gain. © 2007 Thomson - Wadsworth

Causes of Obesity Environment
External cue theory: the theory that some people eat in response to such external factors as the presence of food or the time of day rather than to such internal factors as hunger. © 2007 Thomson - Wadsworth

Short-Term Control of Food Intake
Ghrelin is a hormone release form stomach and stimulate the desire to eat at usual mealtime PYY cause reduction in appetite, release from gastrotentional track after the meal and depends on the proportion of the calorie in the meal. Copyright 2010, John Wiley & Sons, Inc. 61

Causes of Obesity Eating behavior may be a response not only to hunger and appetite, but also to complex human sensations. Often eating is used to relive boredom or to ward off depression. Some people respond to anxiety or to any kind of arousal by eating. © 2007 Thomson - Wadsworth

Weight Gain and Loss WHAT IS THE BEST WAY?
A well-designed low-calorie diet, accompanied by the appropriate exercise program, has actually been observed to promote the same rate of weight loss as, and a faster rate of fat loss than, a total fast. To lose a pound of fat, you need to decrease your intake or increase your expenditure by 3500 Calories. © 2007 Thomson - Wadsworth

Weight-Loss Decisions

Weight-Loss Decisions
Medical aim To reduce the risk of chronic disease To achieve to optimal health How Slow ½ to 2 pounds /week Most from fat tissues not form lean fat Why slow? Rapid weight loss leads to greater losses of water and protein (Drop BMR) People lose weight rapidly are more likely to regain weight Copyright 2010, John Wiley & Sons, Inc.

Weight Loss Strategies
Individualize Your Weight Loss Plan Find the plan that is right for you. Think of it as an eating plan that you will adopt for life. A calorie deficit of 500 calories/day for seven days is enough to lose one pound of body fat a week. Spending an extra 250 calories per day by exercising will increase the calorie deficit. © 2007 Thomson - Wadsworth

Aim for gradual weight loss. Expect to reach a plateau. Aim for a positive gain in lean body mass. Weight loss and bone health. Include adequate calcium and weight-bearing exercise. Adopt a physically active lifestyle. An hour of moderate to vigorous activity on most of day to loss wieght © 2007 Thomson - Wadsworth

Weight Management on the Menu
Watch your serving size Pour chips or crackers into a one-serving bowl rather than eating right from the bag or box. Check labels to see if your portion matches the serving size on the label. Don’t supersize—choose a small drink and a small order of fries. Have a plain burger, not one with a special sauce or an extra-large patty. When you eat out, share an entrée with a friend or take some home for lunch the next day. Cut down on high-calorie foods Have one scoop of ice cream rather than two. Have an apple with lunch instead of a candy bar. Bring your own lunch rather than eating out. Have water instead of soda. Switch to low-fat milk. Balance intake with exercise Go for a bike ride. Try bowling or miniature golf instead of watching TV on Friday nights. Take a walk during your lunch break or after dinner. Play tennis; you don’t have to be good to get plenty of exercise. Get off the bus one stop early. Copyright 2010, John Wiley & Sons, Inc. 71

Weight Gain Strategies
The healthful way to gain weight is to build yourself up by patient and consistent training while eating nutritious foods containing enough calories to gain weight. Choose calorie-dense snacks. Eat more frequently. Spend more time eating each meal: Start with the calorie-dense food first, finish with dessert. Eat regular, balanced meals. First step is medical evaluation Exercise Eat more food and add extra calories. © 2007 Thomson - Wadsworth

ABCs of Behavior Modification

Healthy Diet or Fad Diet?
Most of diets, no matters how outlandish, will promote weight loss. The effective weight loss diet : Weigh loss + maintained over the long term Healthy weigh loss + change in lifestyle Copyright 2010, John Wiley & Sons, Inc.

Healthy Diet or Fad Diet?

Common dieting methods
Provide exchange list Teach meal planning skills Pre-portioned meals or liquid formulas Easy Not teach the food selection skills for long term lifestyle change Low fat diet Moderation (weight loss), limitation Low carbohydrate diet ( moderation) Copyright 2010, John Wiley & Sons, Inc.

Drugs and weight Loss Charastericts of ideal drug: Safe.
Free of undesirable side effects and abuse potential. Effective at reducing body fat. Effective for long-term use in the treatment of obesity. Most available drugs are appetite suppressants. To the date ,none have been proven effective in aiding weight loss. © 2007 Thomson - Wadsworth

Drugs and weight Loss Most available drugs are appetite suppressants. Phentermine Decrease the absorption of the fat Orlistat Should recommend to only individuals whose health is seriously compromised by their body weight. To the date ,none have been proven effective in aiding weight loss. Copyright 2010, John Wiley & Sons, Inc.

Drugs and weight Loss Herbal preparations in the United States are produced and marketed without regulations to ensure their safety or effectiveness. Some side effects can range from nausea and headaches to heart attacks and death. For example, the Chinese herb ephedra, commonly called ma huang, contains ephedrine, a stimulant that mimics the action of the drug phentermine. Ephedrine can cause tremors, insomnia, severe headaches, high blood pressure, heart attacks, and stroke. © 2007 Thomson - Wadsworth

Weight Gain and Loss Surgical Procedures for Obesity:
Gastroplasty: involves stapling the stomach to make it smaller, thus forcing the person to eat less. Nausea and vomiting occur if the person continues to overeat following the procedure. Gastric bypass: is the most common surgery in the U.S., surgery involves a smool pouch near the top of the stomach with staples or plastic band and connected directly to the middle portion of the small intestine. Gastric Banding: reduce the size of the stomach by using an adjustable silicone band or cuff near the top of the stomach to create a pouch that fills quickly and empties slowly. . © 2007 Thomson - Wadsworth

Weight Gain and Loss D. Cosmetic surgery: Such as liposuction: a type of surgery (also called lipectomy) that vacuums out fat cells that have accumulated, typically in the buttocks and thighs. If large calorie intake is continued without expenditure through physical activity, fat will return to the fat cells that remain in those regions. Sometimes it can produce pleasing results, but sometimes it can produce a figure in which one part of the body is disproportionately thin relative to the others. © 2007 Thomson - Wadsworth

The secret is a sensible (not to say easy) three-pronged approach involving: Healthful eating habits Exercise Behavior change Such an approach takes tremendous dedication. Many of those who complete weight loss programs lose about 10% of their body weight, only to regain two-thirds of it back within 1 year and almost all of it back within 5 years. © 2007 Thomson - Wadsworth

The Eating Disorders Anorexia nervosa Bulimia nervosa
Eating disorder: general term for several conditions: Anorexia nervosa Bulimia nervosa Binge-eating disorder …that exhibit an excessive preoccupation with: Body weight Fear of body fatness Distorted body image © 2007 Thomson - Wadsworth

Anorexia nervosa: Literally “nervous lack of appetite,” a disorder
(usually seen in teenage girls) involving self-starvation to the extreme. an = without orexis = appetite For many people with anorexia nervosa, a full day’s diet may consist of no more than 3 or 4 items © 2007 Thomson - Wadsworth

The Eating Disorders Bulimia nervosa, bulimarexia (byoo- LEE-me-uh, byoo-lee-ma-REX-ee-uh): binge eating (literally, “eating like an ox”). Combined with an intense fear of becoming fat and usually followed by self-induced vomiting or the taking of laxatives. buli = ox © 2007 Thomson - Wadsworth

The Eating Disorders Binge-eating disorder: an eating disorder characterized by uncontrolled chronic episodes of overeating (compulsive overeating) without other symptoms of eating disorders. Typically, the episodes of binge eating occur at least twice a week on average for a period of six months or more. © 2007 Thomson - Wadsworth

Factors Contributing to Eating Disorders

Chapter 9 Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein. . Copyright 2010, John Wiley & Sons, Inc. 96

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