Chapter 7 Energy Metabolism January 28th 2011 Energy Balance 65 of adults are overweight Almost half of those are obese 30 of total population is obese Red flags 10 pounds of weight gain 2 inch increase in waist circumference Why the increase in overweight obese Increase in technology Safety issues Junk food Microwaves Marketing Portion sizes Eating styles less family dinners Working more Energy Balance Energy Balance Estimating kcal Content in Food Carbs 4kcal g Protein 4kcal g Fat 9kcal g Energy In vs Energy Out Basal Metabolism Minimum energy expended to keep a resting awake body alive 60 70 of total energy needs Includes energy needed for maintaining heartbeat respiration body temperature Varies between individuals Approximately 1 kcal minute 1440 minutes per day Factors that Influence Basal Metabolism Body surface area weight height Lean body mass Gender Body temperature Thyroid hormone Nervous system activity Age Calorie intake Pregnancy Use of caffeine and tobacco Physical Activity Increases energy expenditure More activity more energy burned Lack of activity is a major cause of obesity Thermic Effect of Food TEF Energy used to digest absorb and metabolize food nutrients Sales tax of total energy 5 10 above the total calories consumed consumed TEF is highest for protein carbohydrate fat Adaptive Thermogenesis Nonvoluntary physical activity Triggered by overeating Fidgeting and shivering Maintenance of muscle tone Maintenance of posture Overeating Increases sympathetic nervous system activity Resists weight gain Brown Adipose Tissue Participates in thermogenesis Determination of Energy Needs Direct calorimetry Measures heat output Expensive and complex Indirect calorimetry practical Measures the amount of oxygen Oxygen consumed is related to energy consumed expended Estimated Energy Requirement EER Men 19 years and older EER 662 9 53 x AGE PA x 15 91 x WT 539 6 Women 19 years and older EER 354 6 91 x AGE PA x 9 36 x WT 726 x x HT HT PA physical activity estimate WT weight in kg HT height in meters inches 39 4 PA WOMEN 1 00 1 11 1 00 Physical Activity Estimate PA MEN ACTIVITY LEVEL Sedentary no exercise Low Activity walks the equivalent of 2 miles day Active walks the equivalent of 7 miles day Very Active walks the equivalent of 17 miles day 1 12 1 27 1 25 1 48 1 45 What is a Healthy Body Weight Current height weight standards Weight associated with health and May not be the healthiest weight for longevity individual Review of family history Personal weight history Healthy lifestyle contribution Weight Related Conditions A Healthy Body Weight What is the lowest weight maintained for more than a year What weight was maintained without constantly feeling hungry Establish a personal healthy weight BMI Overweight and Obesity Underweight BMI 18 5 Healthy weight BMI 18 5 24 9 Overweight BMI 25 29 9 Obese BMI 30 39 9 Severely obese BMI 40 Know these for test Height Weight Table Perspective on Weight Aim for personal healthy weight Avoid unrealistic goals Listen to body s cues for hunger Eat a healthy diet Be physically active Size acceptance Obesity Excessive amount of body fat Women 35 body fat Men 24 body fat Increased risk for health problems Are usually truly overweight Estimation of Body Fat Underwater weighing Very accurate Fat is less dense than lean tissue Fat floats Underwater Weighing Estimation of Body Fat Air displacement Determines the body volume Displace air in a sealed chamber Body density Body wt body volume Body fat 495 body density 450 Bod Pod Skinfold Measurements Estimation of Body Fat Bioelectrical impedance Low energy current that measures the resistance of electrical flow Fat is resistant to electrical flow the more the resistance the more body fat DEXA dual x ray photon absorptiometry X ray body scan that allows for the determination of body fat Most accurate but expensive Dual X ray Photon Absorptiometry Body Fat Distribution Upper body obesity Apple shape Associated with Cardiovascular disease HTN type 2 diabetes Testosterone and excessive alcohol Abdominal fat is released into the liver and promotes inflammation in the body Defined as Waist measurement of 40 for men Waist measurement of 35 for women Body Fat Distribution Body Fat Distribution Lower body obesity Pear shape Encouraged by estrogen and progesterone After menopause upper body obesity more common Fewer health risks than upper body obesity Juvenile Onset Obesity Develops in infancy or childhood Increase in the number of adipose cells Adipose cells have long lifespan and need to store fat Makes it difficult to lose fat weight loss Adult Onset Obesity Develops in adulthood Fewer number of adipose cells Adipose cells are larger store excess amount of fat If weight gain continues the number of adipose cells can increase Obesity and Nature Debate Identical twins When raised apart still have similar weights Genes Affect metabolic rate fuel use brain chemistry body shape Account for up to 70 of weight differences Thrifty metabolism gene More fat storage to protect against famine Set Point Theory Weight is regulated by the body Genetically predetermined body weight Body resists weight change Leptin assists in weight regulation Reduction in calorie intake results in lower metabolic rate Ability to shift the set point weight Opponents of Set Point Theory Weight does not remain constant Different environments can alter weight People settle into a particular weight based on current circumstances Obesity and Nurture Debate Environmental factors influence weight Learned eating habits Activity factor or lack of Poverty and obesity Female obesity is rooted in childhood obesity Male obesity appears after age 30 Nature and Nurture Obesity is nurture allowing nature to express itself Location of fat is influenced by genetics Child of obese parents is especially at risk Increased physical activity and moderate calorie intake can promote healthy weight What Encourages Excess Body Fat What Encourages Excess Body Fat Monday January 31st OBESITY TREATMENTS FOR OBESITY
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