Chapter 10 Weight Management PowerPoint Lecture Slide Presentation created by Karen Schuster Florida Community College of Jacksonville Copyright 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Spot Reducing
What Is Weight Management and Why Is It Important? Weight management: maintaining weight within a healthy range. Healthy weight is one that doesn t increase the risk of developing weight-related health problems and diseases. Overweight: 10-15 lbs. more than healthy weight 68% of Americans are overweight. Obesity: 25-40 lbs more than healthy weight 34% of Americans are obese.
What Is Weight Management and Why Is It Important? Being overweight increases risk of hypertension, stroke, heart disease, gallbladder disease, type 2 diabetes, osteoarthritis, some cancers (i.e.colon, breast, uterus) and sleep apnea. Losing as little as 10-20 lbs. reduces risk Underweight: weighing too little for your height May be caused by: excessive calorie restriction and/or physical activity, underlying medical condition, emotional stress At risk for low body protein and fat stores and a depressed immune system (particularly elderly)
What Are The Risks From Underweight? Deficient body fatness threatens survival during a famine or during diseases. Underweight also increases the risk for any person fighting a wasting disease.
BMI Body Mass Index An index of a person s weight in relation to their height. It is associated with degree of health risk.
The Problems of Too Little or Too Much Body Fat
How Do You Know If You re at a Healthy Weight? Measure your BMI: Body mass index (BMI) = weight (lbs) x 703 128 * 703 = 89984 /5*12=60+9=69inches*69=4761 =18.9 height squared (in 2 ) BMI > 25 is overweight: modest increase in risk of dying from diseases > 30 is obese: 50 100% higher risk of dying prematurely compared to healthy weight < 18.5 is underweight, can also be unhealthy
Body Mass Index (BMI) The BMI standards are not accurate for athletes and pregnant women. It is not a direct measure of your % of body fat.
How Do You Know if You re at a Healthy Weight? Pg. 259 Measure your body fat and its location: Average healthy adult male between 20 49 years of age: 16 21% of weight is body fat Average healthy female: 22 26% body fat Techniques for measuring amount of body fat: skinfold thickness measurements, bioelectrical impedance, dual-energy x-ray absorptiometry, underwater weighing (Gold Standard) and air displacement Central obesity (excess visceral fat) increases risk of heart disease, diabetes, and hypertension. Measure waist circumference
Ways to Measure Percentage of Body Fat Table 10.1
Ways to Measure Percentage of Body Fat Table 10.2, cont.
Energy In and Energy Out The energy in foods and beverages is the only contributor to the energy in side of the equation The energy out side is more difficult to determine and has to do with lifestyle and metabolism 1 lb body fat = 3,500 calories
What Is Energy Balance and What Determines Energy Needs? Energy balance is calories in versus calories out. Positive energy balance: consume more calories than expend, leads to fat storage, weight gain Negative energy balance: calorie intake falls short of needs, leads to weight loss Energy needs are different for everyone. Energy needs comprised of: Basal metabolism Thermic effect of food amt of kcals used to digest, absorb and process food. Physical activities (the easiest to alter)
How Many Calories Do I Need Each Day? Two major components of the energy out side of the body s energy budget are basal metabolism and voluntary activities. Basal metabolism Sum total of energy expended on all of the involuntary activities needed to sustain life Excludes digestion The hormone thyroxine directly controls basal metabolism. A third component of energy expenditure is the thermic effect of food.
What Is Energy Balance and What Determines Energy Needs? Your BMR will increase your energy needs. Minimum energy needed to keep you alive (meet basic physiological needs) Makes up about 60% total energy needs The amount of lean body mass you have affects your BMR Many factors affect BMR (Table 10.2) The thermic effect of food affects your energy needs. Amount of calories expended to digest, absorb, and process food (about 10% of calories in food eaten)
Factors That Affect Your Basal Metabolism Rate Table 10.2
Factors That Affect Your Basal Metabolism Rate Table 10.2, cont.
The Body s Response to Fasting If a person goes without food for 3 days, the body makes several adjustments: Less than a day into the fast, the liver s glycogen is used up. Where can the body obtain glucose to keep its nervous system going? Not from fat, because fat cannot be converted to glucose. Not from muscle glycogen, because they keep it for their own use.
The Body s Response to Fasting The body sacrifices the protein in its lean tissue to supply raw materials from which to make glucose. If the body were to continue consuming its lean tissue unchecked, death would occur in about 10 days. (Death occurs when either fat stores are depleted or half the body s lean tissue is gone.) To prevent death, the body converts fat to ketones to help feed the nervous system and help spare tissue protein.
The Body s Response to Fasting After about 10 days of fasting, the brain and nervous system can meet most of their energy needs using ketone bodies. Thanks to ketosis, a healthy person starving with average body fat content can live totally without food for as long as six to eight weeks.
What Are the Effects of an Energy Imbalance? Too many calories can cause one to become overweight. Excess calories stored as fat, regardless of source Limited capacity to store glucose as glycogen Can t store extra protein Unlimited capacity to store fat Body contains about 35 billion fat cells, which can expand. The number of fat cells we have remains the same, they are enlarged as we consume excess calories, not multiplied.
What Factors Are Likely to Affect Body Weight? What and how often you eat, physiology, genetics, environment all play role in weight management Hunger and appetite affect what you eat. Appetite is psychological desire for food Hunger is physiological need for food, subsides as feeling of satiation sets in Satiety determines length of time between eating episodes
Why Did I Eat That? Eating behavior seems to be regulated by signals that fall into two broad categories: go mechanisms that stimulate eating and stop mechanisms that suppress eating Where is the brain center for hunger and satiety? Hypothalamus
What Factors Are Likely to Affect Body Weight? Genetics play a role in determining body weight Risk of becoming obese doubles if parents are overweight, triples if obese, five times greater if severely obese For someone with at least one obese parent, the chance of becoming obese is estimated to fall between 30 and 70 percent. Confirmed by studies of identical twins separated at birth
What Factors Are Likely to Affect Body Weight? Environmental factors can increase appetite and decrease physical activity. Environment of cheap and easily obtainable energydense foods stimulate appetite We work more and cook less. About 1/3 calories come from ready-to-eat foods prepared outside of home Frequent dining out associated with higher BMI
What Factors Are Likely to Affect Body Weight? We eat more (and more) Increased availability of food service establishments, access to large variety of foods, larger portions encourage people to eat more We sit more and move less Americans eating about 300 calories/day more than in 1985 Labor-saving devices at work and home, sedentary leisure activities ( screen time ) result in decreased energy expenditure
Achieving and Maintaining a Healthy Body Weight What is considered safe weight loss? Slow 1 to 2 lbs per week. Yo-Yo Dieting is rapid weight loss with rapid regain.
What Diet Strategies Are Best for Weight Loss? Energy in must be less than energy expended Calorie intake must decrease to attain weight loss
Physical Activity for Weight Loss Physical activity greatly augments diet in weight-loss efforts. Improvements in health and body composition follow an active lifestyle. Spot Reducing Exercise cannot remove fat from any one particular area
How Can You Lose Weight Healthfully? Successful long-term weight loss requires changes in three areas: diet, physical activity, and behavior Eat smart, because calories count: add satiation to lowcalorie meals by including higher-volume foods Eat more vegetables, fruit, and fiber Include some protein and fat in your meals Protein increases satiety most Fat slows movement of food from stomach into intestines Choose lean meat, skinless chicken, fish, nuts, and unsaturated oils.
How Can You Lose Weight Healthfully? Move to lose 60 minutes/day of moderate-intensity activities can prevent becoming overweight and aid in weight loss 10,000 steps/day (5 miles) can reduce risk of becoming overweight Break bad habits Behavior modification: change behaviors that contribute to weight gain or impede weight loss Techniques include keeping food log, controlling environmental cues that trigger eating, managing stress
Fad Diets Are the Latest Fad Research shows that reduction of calories, not the composition of the diet, is effective in weight loss. People who adhere the longest to weight-loss diets lose the most weight. High drop-out rates for most extreme diets (Atkins diet)
How Can You Gain Weight Healthfully? Gaining weight for the underweight is as challenging as losing weight for the overweight. Need to add at least 500 calories to daily energy intake for gain of 1 pound/week Weight gain requires a diet of calorie-dense foods, eaten frequently throughout the day. Examples: waffle instead of toast, coleslaw instead of cabbage Physical activity builds lean tissue, and no special supplements can speed the process.
Kilocalories How are kilocalories in food determined? Bomb Calorimeter Overall what is the best approach to long term, safe weight loss? Decrease calories and increase output
What Is Disordered Eating and How Can You Identify It? Disordered eating: abnormal and potentially harmful eating behaviors that do not meet specific criteria for eating disorders Eating disorders: psychological illnesses that involve specific abnormal eating behaviors and other factors About 11 million in U.S. struggle with eating disorders Most are adolescent or young adult white, middle/upper-middle class females, but increasing in males, minorities, and other age groups
What Is Disordered Eating and How Can You Identify It? Anorexia nervosa results from severe calorie restriction. Self-starvation and excessive weight loss Intense fear of being fat Distorted body image: see themselves as fat when underweight Health consequences: Electrolyte imbalance (low blood potassium) can be fatal. Drops in body temperature, lanugo, decrease in heart rate and blood pressure, osteoporosis
What Is Disordered Eating and How Can You Identify It? Bulimia nervosa involves cycle of binge eating and purging Purging can include self-induced vomiting, excessive exercising, strict dieting or fasting, abuse of diet pills, laxatives, and diuretics Vomiting can cause tears in esophagus, swollen parotid glands, tooth decays, gum disease, broken blood vessels in eyes Potentially fatal electrolyte imbalance can also result from bulimia.
What Is Disordered Eating and How Can You Identify It? Binge eating disorder involves compulsive overeating (without purging). Eat in secret, feelings of shame Health effects are those associated with obesity. Night eating syndrome is a type of eating, sleeping, and mood disorder. Majority of calories consumed after evening meal and wakes up at night to eat Most common among obese and associated with low self-esteem, depression, stress
Factors That Contribute to Eating Disorders Figure 10.13
How Are Disordered Eating Behaviors Treated? Multidisciplinary teams is most effective approach Psychological, medical, and nutrition professionals Nutritional approaches include: Identifying binge triggers, safe and unsafe foods, hunger and fullness cues using food journals Meal plans to ensure intake of adequate calories and nutrients for anorexia nervosa and to help avoid overeating with bulimia nervosa and binge eating disorder Recovery can be slow; no quick fix Greater success if treated in early stages