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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 fatnot 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 fatnot 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 rolefew 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 independentlynot like friends who eat too much The gratification gained from overeating is brieffeeling 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 Bodys 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, activitys 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 thingbody 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 Americas Eating Smart Menu http://www.shapeup.org/publications/eating.smart/textmenu.htm Eating Disorders Info/Help http://www.health4teens.org/eating
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