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Energy Expenditure

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Energy Expenditure

1. 1. Energy Balance and Obesity 10/01/2005 18:43:00 ←Energy Expenditure • Calorie (always capitalized) = 1000 calories (chemical) of 1 kcal • Approximately 2500 kcal/day (ballpark number) • Basal Metabolic Rate (BMR) o breathing, kidney function, etc. – when awake o about 50-55% of total energy expended as BMR – this value is going up as people become more seditary ←Energy Equivalents of Foodstuffs • Protein 4.3* = higher outside of body due to O2? • RQ = respiratory quotient o 1.0 is carbohydrates o 0.7 is mostly fat o inbetween cannot tell content but protein is in there ←Weight Loss Problem • 2300-1700 = 600 kcal/day • 600 *7days = 4200 kcal/week deficit • = ~ 1lb if using 4.3 kcal/gm ←Basal Metabolic Rate (BMR) • Energy liberated can be calculated by measuring O2 consumption (4.825 kcal/L O2) • Standard calculation of BMR o Rested test subject
2. 2. o o o in notes ←Expression and Calculation of BMR • BMR is expressed as kcal/m2 body surface area/hour. It is usually reported as a % aboce or below normal values • calcularion of BMR o 15 liters – O2 consumed/hour o X 4.825 – Calories/ L O2 o 72.4 Calories/hour o divide by 1.5 m2 o 48.3 o normal rate is 38.5 o person appears to be hyperthyroid due to high BMR • Figure showing Male vs Female and a decrease in age • Table for Body Surface Area Determination o review your conversions  2.54 cm = 1 inch  1 kilogram = 2.2 lb ←Body Mass Index (BMI) • to determine BMI, divide body weight in KILOGRAMS by HEIGHT in meters squared (kg/m2) • see slide
3. 3. • table showing BMI o average male height is 5’ 9” ideal weight is 155 lbs o all of this came from life insurance tables • Popular description o Thin - < 18.5 kg/m2 o Normal – 18.5- 24.9 kg/m2 o Oveweight – 25 – 29.9 kg/m2 o Obese – 30 – 39.9 kg/m2 o Morbid obesity > 40 kg/m2 • Body fat o 15-20 for men o 25 normal for women (what was the range) o body fat increases with age ←Obesity • declared disease in 1984 – but this is debatable o CDC says this is the number one health threat currently • nearly 2/3 of the US is overweight o 1/3 is obese • is increasing • Figure showing last years data • figure showing increase in BMIs compared 1960 to 2000
4. 4. • overweight in paper means obese in order to PC for the children ←Figure not in my slides – Mean food Energy Intake Per Individual in 1977 and 1985 • do not have to memorize the numbers shown on this slide • shows increase in kcal/day diet – due to fast food and cokes and what not – this coupled with less activity equals weight gain ←Genetic vs. Environmental Components of Obesity • if you are overweight as a child and both parents are overweight you have 80% chance of being overweight at there age • if only one parent is overweight… • Adopted children to obese parents seem closer to birth parents • go from top of social tier down obesity increases ←Risk Factors and Health Problems associated with obesity • location of adipose tissue o android – male – upper body obesity o gynoid – female – lower body obesity  this is extremely resistant fat pad • Helath problems of obese – if young and obese there is a lot more risk than if you are obese later in life o hypertension o hypercholesterolemia o heart attacks, strokes o type 2 diabetes o gall stone disease – primarily in women, linked to cholesterol o specific cancers
5. 5. • Metabolic Syndrome (Syndrome X) o Characterized by:  Obesity  hyperinsulinmia  high blood pressure  dyslipidemia - high triglycerides and low HDL o more stuff on slide ←Theories of the Cuases of Obesity (multiple) • Lipostat theory o Hormone from fat cells (leptin) controls feeding  Probably sensitivity to leptin they thought  looked at receptor but did not really work out so people started to think about hypothalamic disfunction • Hypothalamic disfunction o Ventrolateral nucleus – feeding o • Depressed thermogenic response o Upon overeating, obese people don’t burn off excess calories  Less brown fat? – nope not physiological significant • Decreased activity o Obese people are less active • Etc.
6. 6. ←Hyperinsulinemia • Retype the slide • spare receptors - receptors left over after response has been created • figure showing plasma insulin vs hours after glucose challenge o thin diabetic – type I diabetes • figure showing receptor kinase/insulin bound for non-obese, obese and … ←Social Consequences of Obesity • Children hate fat people thanks to their parents ←Weight Loss Benefits: • See slide ←Treatments of Obesity • Dietary o Conventional dieting o starvation diets – lose both fat and muscle o liquid protein fasts o ketogenic diets (vlcd - very low calorie diets)  optifast – starvation with protein supplement • Surgical o Gastric bypass – usually for the massive obese o jaw wiring o liposuction • Drug o Amphetamines ←Etc