Lecture Notes-8
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•          Body Weight Control

•          Key Principles for Weight Control

•          There is no quick and easy way to lose fat permanently

•          Focus on losing body fat—not body weight

•          Lose fat sensibly with reasonable habits for lifelong maintenance

–        Eat reasonably less

–        Be reasonably more active (exercise)

–        Change the way you think about food

–        Practice behavior modification

–        Prepare for inevitable relapses

 •          Overweight and Obesity

•          Overweight:

–        Weighing too much for height

–        Normally calculated by some combination of weight/height

•          Obesity:

–        Point at which excess body fat can lead to serious health problems

–        Being greatly overweight to the point of being at risk for health problems is also considered “obesity” 

–        Calculated by some measure of body fat (%BF)

–        (body mass index)   BMI of ≥ 30

–        (percent body fat)  Men:  ≥ 25 %BF     Women:  ≥ 32 %BF

–        Obesity Epidemic

–        Point at which excess body fat can lead to serious health problems

–        Has reached epidemic proportions in developed countries

–        Obesity and unhealthy lifestyle habits are the most critical public health problems of the 21st century

–        Obesity is the 2nd leading cause of preventable death behind tobacco use

–        Obesity & Overweight contribute to many ailments:

•          Heart disease

•          Diabetes

•          Cancer

•          Other               

•          Overweight and obesity in US have increased dramatically

–        Has reached epidemic levels

–        Prevalence even higher in African American & Hispanic Americans

–        More than ½ US adults are overweight (>25 BMI)

–        More than Ό US adults are obese (>30 BMI)

–        Average weight of US adults has increased by 15 pounds

–        Total cost to treat obesity-related diseases > $100 billion/yr

–        > $40 billion/yr spent in weight loss

•          > 30 lbs overweight during middle age (30-49) may lose ~7 years of life

•          10-30 lbs overweight during middle age (30-49) may lose ~3 years of life

•           Decreases are similar to tobacco

•          Severe obesity (> 45 BMI) at a young age may lose up to 20 of life

•          Also loss of “quality” of life

•          Even a reduction of 5-10% body weight can reduce risk for heart disease, diabetes, other

•          Underweight

•          Weighing too little for height

•          Having too little muscle & fat tissue to the point of being unhealthy

•          About 14% of US is underweight

•          Health problems from being underweight:

–        Heart damage

–        Gastrointestinal problems

–        Shrinkage of internal organs

–        Immune system abnormalities

–        Disorders of the reproductive system

–        Loss of muscle tissue

–        Damage to the nervous system

–        Death

•          Body Composition Analysis

•          Composition of the human body:

–        Fat Component - Percent Body Fat (%BF)

•          Adipocytes (fat cells)

–        Non-fat Component – Lean Body Mass (LBM)

•          Mostly muscle tissue


Methods of Determining “Overweight”

•          Height / Weight Charts

–        Recommended weight for height according to gender & frame size based upon life insurance tables

–        Weakness: does not consider “fat” content and, therefore, is not a good individual indication of health risk

   •          Body Mass Index (BMI) =   wt [kg] χ ht [m2]

–        Multiplying body weight in pounds by 705 and dividing the square of height in inches is the easiest formula

–        Most widely used in large, epidemiology studies due to its simplicity and not requiring lab equipment

–        Weakness: fails to differentiate between fat and lean body mass (still only considers weight per height)

•          BMI = 18.5 or <      underweight

•          BMI = 18.5-24.9     normal

•          BMI = 25-29.9        overweight

•          BMI = 30-34.9        obese  I

•          BMI = 35-39.9        obese  II

•          BMI = > 40             obese III           

–        More than 1/5 of US adult population has a BMI of 30 or more


•          Methods of Determining “Body Fat”

•          Dual-Energy X-Ray Absorptiometry (DEXA)

•          Hydrostatic Weighing (underwater weighing)

•          Air Displacement (Bod Pod)

•          Skinfold Thickness

•          Bioelectrical Impedance (BEI)

•          Girth Measurements

•          Body Mass Index (BMI)

•          Key Principles for Weight Control

•          There is no quick and easy way to lose fat permanently

•          Focus on losing body fat—not body weight

•          Lose fat sensibly with reasonable habits for lifelong maintenance

–        Eat reasonably less

–        Be reasonably more active (exercise)

–        Change the way you think about food

–        Practice behavior modification

–        Prepare for inevitable relapses

 •          The Weight Loss Dilemma

•          Attempting to attain a “perfect” physique

–        Heredity plays a big role—few people have the genes for a “perfect” body

–        Media & health club influence distorted

–        May lead to eating disorders

–        May lead to lifelong emotional preoccupation

•          Traditional weight loss plans w/o behavioral modification and exercise are not effective

–        Only 10% lose desired weight

–        Only 5% capable of keeping weight off

•          Studies indicate most people underestimate energy intake and overestimate energy expenditure

–        Difficult to efficiently track behavior

–        Overweight Versus Obesity

•          Unreasonable weight loss methods (fad diets)

–        Most fad diets are very low calorie

•          Deprive body of nutrients

•          Can result in metabolic imbalance

•          Body is highly resistant to permanent weight loss through “crash” dieting

–        Most are designed for short-term “weight” loss

•          Difficult to maintain for life

•          Health consequences

•          May lead to “yo-yo” dieting

–        As unhealthy as being overweight

•          At least ½ weight loss is lean muscle tissue plus water

–        Slows metabolic rate

–        Does not reduce fat component significantly

–        Can be expensive

•          Involve some “catch” for profits

•          Can be difficult to plan and shop for

•          May involve purchased foods, supplements, and lab tests

–        Do not promote exercise component

•          Need to be very restrictive with eating

•          Result in loss of mostly lean muscle tissue and water

•          Exercise is an effective long-term weight control component

–        Do not promote behavior modification

•          Difficult to maintain

                 –        Example: Low carbohydrate/high protein diet (LCHP)

•          Based upon fact that a diet too high in carbohydrate results in storage as body fat (even if fat intake is low)

•          Most weight loss lean muscle tissue & water

–        Weight is lost as water leaves (large component of Carbohydrate)

–        Glucose produced from proteins (lean tissue) to replace low glucose

•          Typically high in fat

•          Too little fruits, vegetables, fiber, phytochemicals, etc.

•          May lead to irritability, fatigue, lightheadedness, decreased mental functioning, constipation, etc.


•          Sensible Weight Loss

•          Eat Reasonably Less

–        Stay within recommended balanced diet for carbs, fat, protein

•          55-60% carbs, <30% fats, 12-15% protein

–        Eat a variety of foods in moderation

–        Choose foods easy to obtain and prepare

–        Make reasonable cuts in caloric intake

•          Based upon lifestyle, current eating and activity habits

•          A reasonable reduction might be to multiply current body weight by 5 and subtract this amount from daily caloric intake

•          Do not consume less than 1500 calories (men) and 1200 calories (women)

–        Cut fat intake

•          Cut butter, cheese, and fried foods

•          Limit red meat

–        Do not skip meals

–        Do not eat late, heavy meals

 •          Be reasonably more active

–        Gradually work up to 60-90 minutes of exercise, most days of the week

–        Try to burn at least 1500 calories per week by exercising

•          300 calories X 5 days per week = 1500 calories per week

•          Do not forget: exercise is not an effective “short-term” weight loss method, but an excellent “long-term” method

–        5 days per week minimum for weight control

–        Moderate, continuous, rhythmical, low-impact activities are best

•          Ex. Walking, jogging, cycling, swimming, skating

–        Increase recreational activities as part of exercise

•          Ex. Hiking, tennis

–        Increase opportunities to be physically active during daily activities

•          Ex. Stairs, walking

 •          Change the way you think about food

–        Eat more for hunger (physiological) than appetite (psychological)

–        Do not use food for gratification (to feel good)

•          Substitute other activities

–        Think independently—not like friends who eat too much

–        The gratification gained from overeating is brief—feeling trim lasts all day! 

–        “Nothing tastes as good as being trim feels”

 •          Practice Behavior Modification

–        Substitute other activities for overeating--do not use food for gratification (to feel good)

–        Be aware of your environment (places and people who entice you to overeat)

–        Eat slowly

–        Eat smaller portions

–        Cut out bad foods

•          Fried, cheese, butter, red meat, desserts

–        Keep reasonable records of eating and activities

–        Set and keep reasonable goals

–        Use support groups

–        Handle stress and social events by preparing in advance

–        Read and listen to positive information about eating correctly

–        Occasionally reward yourself

 •          Prepare for inevitable relapses

–        Expect some relapses from time-to-time and get back on track as soon as possible

–        Set a date to resume correct eating habits

–        Do not consider a brief relapse as “failure.” Beware of the “perfectionist” syndrome when practicing life-long habits

–        Learn from your relapses

•          What causes them and when?

•          Is your diet too restrictive?

•          Are you following the guidelines for sensible weight loss?

–        Read and listen to positive information about he health benefits from proper nutrition


•          Physiology of Weight Loss

•          The causes of obesity are complex

–        Genetics

–        Psychological

–        Lifestyle-Behavioral

•          Energy-balance equation

–        Caloric intake vs. caloric expenditure

–        If intake exceeds expenditure = weight/fat gain

–        If expenditure exceeds intake = weight/fat loss

     •          Energy Intake

–        Food (caloric) intake

•          Energy Expenditure      (3500 calories = 1 lb fat)

–        Resting Metabolic rate (RMR) – 60-70% of daily expenditure

•          Body’s vital processes in resting state

•          Any variation in RMR makes a big difference in weight/fat gain

•          RMR closely tied to lean (muscle) tissue

–        Thermic effect of food (TEF) – 5-10% of daily expenditure

•          Digest, absorb, store food

–        Physical activity – 15-30% of daily expenditure

•          Work, planned exercise, activity’s of daily living (ADLs), recreation

 •          The “Setpoint” Theory

–        Weight-regulating mechanism for controlling appetite, metabolic rate, and amount of fat stored

–        Tends to keep weight/fat within a certain range (setpoint) and resists dramatic weight/fat gain or loss

–        Genetic/evolutionary mechanism for body fat storage and survival

–        Works like a thermostat:

•          if body fat increases > appetite decreases and RMR increases

•          If body fat decreases > appetite increases and RMR decreases

•          Especially sensitive to quick, dramatic weight loss caused by severe restrictions in calories (<800 calories)

–        Lowering the Setpoint:

•          Long-term exercise, diet high in complex carbohydrates, nicotine, and amphetamines (last two dangerous)


•          Weight-loss Myths

•          Spot-reduction of body fat

–        No such thing—body fat loss occurs because of a negative caloric balance with decreases of fat stores from all parts of the body in roughly the same order as when it was put on

–        You cannot “target” certain sites with special exercises

–        Genetic and gender disribution

•          Cellulite

–        Nothing but enlarged fat cells that bulge out from accumulated body fat

•          “Silver-bullet” “secret” body fat reduction methods

–        Nothing safe and significantly effective would remain a secret in the scientific community


•          Eating Disorders

•          Medical illnesses that involve critical disturbances in eating behaviors

–        Characteristics

•          Anorexia nervosa and bulimia nervosa are common in industrialized countries

–        Common in women, ages 25 to 50

–        1 in 10 men have an eating disorder

•          Genetic and environmental influences

•          Anorexia nervosa

–        Fear of gaining weight is greater than death from starvation

–        Obsessive compulsive disorders are common

–        Physical changes due to malnutrition

–        Diagnostic criteria

–        Treatment

•          Bulimia nervosa

–        More prevalent than anorexia nervosa

–        Characteristics

•          Physical

•          Behavioral

–        Binge-purge cycle

–        Health issues associated with bulimia

–        Treatment

•          Binge-eating disorder

–        Most common of three disorders

–        Characteristics

–        Causes

–        Symptoms

–        Treatment

•          Physiology of Weight Loss

•          Three false weight control assumptions

–        All fat people just eat too much

–        The human body does not care how much fat it stores

•          Causes of obesity are complex

–        Genetics

–        Behaviors

–        Lifestyle factors

•          Energy-balancing equation

–        Caloric input equals output will result in weight maintenance

•          Weight gain

•          Weight loss

–        Estimated energy requirement (EER)

•          Resting metabolic rate

•          Thermic effect of food

•          Physical activity

•          Set-point theory

–        Weight-regulating mechanism

•          Controls appetite

•          Controls amount of fat stored

–        Thermostat for body fat

–        Genetic influence

–        Dietary restriction

•          Very low-calorie diets

•          Set-point theory

–        The body “register”

–        Factors that lower the setpoint

•          Exercise

•          Diet high in complex carbohydrates

•          Nicotine

•          Amphetamines

–        Factors that raise the setpoint

•          Diet and Metabolism

•          Amount of lean body mass lost depends on caloric limitation

•          Types of diets

–        Caloric restriction alone

–        Caloric restriction and exercise

•          Basal metabolism and lean body weight

•          Body fat changes with age

•          Diet and Metabolism

•          Exercise: The Key to Weight Management

•          Exercise

–        Maintains lean tissue

–        Enhances rate of weight loss

–        Vital for weight loss maintenance

•          Duration and frequency of exercise for weight loss

•          Combining diet and exercise results in greater weight loss

•          Exercise: The Key to Weight Management

•          Combining aerobic and strength training

–        Works best for weight loss

•          Aerobic exercise offsets setpoint

•          Strength training increases lean mass

•          Resulting weight loss from exercise will take several weeks to notice

•          Low intensity vs. high-intensity exercise

•          Healthy Weight Gain

•          Exercise is the only healthy way to gain weight

–        Strength training is the best approach

–        Add 500 nutrient dense calories per day

•          Carbohydrates and proteins

•          Nutritional accompaniments to training

–        Time of day

–        Pre-exercise and post-exercise snacks

•          Weight-Loss Myths

•          Cellulite

–        Enlarged fat cells

•          Spot reducing

–        Fat comes off throughout the entire body

•          Other myths

–        Rubberized sweatsuits

–        Steam baths

–        Mechanical vibrators

•          Losing Weight the Sound and Sensible Way

•          Regular exercise and food management are sound and sensible

•          Cautions

–        Consult physician prior to exercise program

–        Start slowly and be careful of injuries

–        Sensible caloric intake

–        Wise food choices

•          Estimating daily caloric requirement

–        Based on age, total body weight, and gender

–        This is only a target guideline for weight control

•          Needs periodic adjustment

–        Minimum caloric intakes

–        Caloric distribution of nutrients

•          Reducing your fat intake

–        Long-term successful weight-loss and management programs are low in fat content

–        Time of day when food is consumed

–        Skipping breakfast and weight control

–        Time of day when fats are consumed

•          Monitoring Your Diet With Daily Food Logs

•          People who monitor their intake are more successful at losing weight

•          Aspects of food intake to watch

–        Serving sizes

–        Food labels

–        Meal preparation

–        Caloric intake

•          Applying Behavior Modification to a Weight Management Program

•          Weight management requires behavior modification

•          There is no quick and easy way to take off excess body fat

•          Relapses are almost inevitable

–        Common reasons for relapse

•          Failure is when you give up, not when you make a mistake

•          Weight Control Web Sites

•          Weight Management

–        http://www.wellweb.com/nutria/weight_management.htm

•          Nutrition Analysis Tool

–        http://www.ag.uiuc.edu?~food-lab/nat

•          Count Your Calories

–        http://www.bgsm.edu/nutrition/in.html

•          Shape Up America’s Eating Smart Menu

–        http://www.shapeup.org/publications/eating.smart/textmenu.htm

•          Eating Disorders Info/Help

–        http://www.health4teens.org/eating