Week 2 notes for Exam 3. 10-27 and 10-29
Week 2 notes for Exam 3. 10-27 and 10-29 NUTR 400 L21
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This 8 page Class Notes was uploaded by Madison Krasko on Monday November 2, 2015. The Class Notes belongs to NUTR 400 L21 at University of New Hampshire taught by Professor Jesse Morrell in Summer 2015. Since its upload, it has received 23 views. For similar materials see Nutrition Health & Well Being in Biological Sciences at University of New Hampshire.
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Date Created: 11/02/15
Week of 10/26-10/30. Week 2, Notes for Exam 3 I am not paid by the University. I am a student in this class taking my notes on the lectures and the readings. This notes combine the notes from the lecture and the reading assignments. Lecture 10/27 Energy Balance Energy Balance= Calories In vs. Calories Out Positive Energy Balance= Increase in Body Mass. Consuming excess calories. Negative Energy Balance= Decline in Body Mass. Consuming fewer calories. Energy= the capacity to do work Scientists measure energy in calories 3500 kcal= 1 pound Energy out—Total Energy Expenditure (TEE) 3 Major Components: 1) Resting Energy Expenditure (65%) 2) Physical Activity (25%) 3) Thermal Effect of Food (10%) 1) Resting Energy Expenditure (REE) a. “cost of living”; calories burned in your daily living activities b. about 2/3 of energy out c. also called BMR (Basal Metabolic Rate) *Why would people have different REE’s even if they are the same size?? -Height. If taller, there is more surface area and a higher metabolic rate is needed -LEAN MUSCLE MASS---- the primary differential -The more Lean Muscle, the higher your metabolic rate. 2) Physical Activity a. High Variable b. 15-30% of energy requirements c. dependent on intensity and duration of activity 3) Thermic Effect of Food a. Also called- Induced Thermogenesis b. Amount of energy used to process food c. Estimated 5-10% of energy intake *Adaptive Thermogenesis -Energy spent to adapt to dramatic circumstance change -example= illness, trauma, cold temperature, over feeding NEAT -Nonexercise Activity Thermogenesis -Energy spent for certain movements -Movements such as: posture or fidgeting *Fasting decreases resting energy dependiture (metabolic rate) *Resting Energy Expenditure (REE) accounts for the majority of TEE Measuring Energy Out 1)Direct Calorimetry -measures body heat released 2) Indirect Calorimetry - Measures Oxygen consumed and Carbon Dioxide expired -Can then calculate calories expended 3) Stable Isotopes -Doubly labeled water (molecules) -Accurate but Expensive (measures excreted water) 4) Formulas- estimation! - hundreds available -REE -TEE or EER -Shorthand Method *example=== TEE= REE x AF x IF TEE= total energy expenditure (kcals) REE= Resting energy expenditure (kcals) AF= activity factors IF= Injury Factor… only if applicable -need to know sex and weight Calculating REE -Woman: 0.9 x Body Weight in Kg x 24 - Men: 1.0 x Body Weight in Kg x 24 Determining AF and IF (if there are any) will be stated *Remember… Weight Stable individuals are in relative energy balance 1) Mike eats 2500 kcal/day. If Activity Level (AL) stays the same, how many kcal/day should he eat to lose a pound a week? * To lose a pound a week, that’s 3500 kcal *If you decrease 500 calories per day: -500x7 = 3500. The 3500 being lost woild make him lose 1 pound per week 2) Lean Body Muscle/ Mass === The most significant predictor of resting energy expenditure. (aka- basal metabolic weight) Why is Body Weight and Composition Important? Body Weight: -Body Weight is a traditional and easy health measure -Various assessment tools height/ weight charts formulas Body Mass Index: personsweight∈Kg Ratio of---- --persons height∈Meters associated with chronic disease risk *example= Jake= 6 ft. tall and 176 pounds 176/2.2 pounds/Kg= 80 Kg 72 (in.) x 2.54 (cm/in) = 182.9 cm = 1.83 Meters 80 kg/1.83 m= 23.9 kg/m=== JAKES BMI underweight: Below 18.5 healthy : between 18.5- 24.9 overweight: 25-29.9 Obese: greater than 30 BMI Limitations -Body fat distribution -Body composition. It doesn’t differentiate muscle and fat Overweight VS. Overfat -weight only indirect measure of body composition - body composition: fat mass and fat-free mass -desirable amounts of total body fat: Men= 6-24% Women= 9- 31% How is Body Composition Measured 1) Skinfold Thickness -pull skin away from muscle and measure. Error rate of 3- 5% 2) Bioelectrival Impedance -Electric impulses sent through body. Error rate of 3-5% 3) Densitometry : -Displaced fat. Bod Pod or Wnderwater weighing 4) DEXA: -high end x-ray, very accurate but very expensive and admits radiation -used for bone health What about Fat Distribution?? Visceral Fat vs. Subcutaneous Fat Visceral= in abdominal muscle area, around the organs. Men more likely to have Subcutaneous = In other Regions (butt and thighs) -women more likely to have -Unlike visceral fat, subcutaneous is not linked to health risks -subcutaneous fat is harder to lose -Lower Body Obesity: Gynoid, Resist Weight Loss -Upper Body Obesity: Andriod, Chronic Health Risks -Hormonal Influence: Menopause, Causes switch to Android weight gain Assessment -CT and MRI can measure this -Tape Measure= waist circumference -weight circumference= circle at top of iliac crest -simple but useful assessing central adiposity -Central Adiposity = risk of diabetes, heart disease, stroke, hypertension -Recommended: Men= under 40 in. Female: ender 35 in. -Waist Circumference can be used to measure body fat distribution Energy Balance And Obesity Notes On Readings for 10-27 Lecture Obesity= having excess Body Fat Biology of Hunger -Short Term and Long Term ways to regulate energy balance Short Term === mediated by hormones and stomach pressure that are responsible for hunger Long Term === different set of hormones, adjusts food intake and energy expenditure to store fat. Short Term Energy Balance (Meals): Decrease in energy-yeilding macronutrients Increase in hormones signaling low energy Increase Ghrelin in stomach Brain sends the Increase Hunger Sensation EAT! Long Term Energy Balance Increase Adipose Tissue Increase Leptin Brain decreases hunger We eat less *Stomach Grumbling= Ghrelin (the hunger hormone) activates neurons in brain to tell the body it needs food *Satiety= the effect our food has on our interest in eating after the meal -this works in between meals and effects when we feel hungry again 2 things that effect these most: 1- Gastric Distention== how much stomach expands 2- The release of hormones made by specialized cells in the gastrointestinal tract *Nerves in stomach sense expansion and relay signals to the brain to send a feeling of fullness *At the same time- gut peptide hormones in Small Intestine (S.I.) are made after nutrients in gut detected *Leptin = hormone made by adipose tissue. Plays roles in body fat regulation and long-term energy balance. when fat stores increase, leptin increases when leptin increases, signals are sent to the brain to suppress hunger Hunger and Appetite Hunger vs. appetite= Major Hunger= biological need for food Appetite= a desire for food. Sensory stimuli -fat gain in different in everyone Total Energy Expenditure (TEE) 1-Basal Metabolism 2-Thermal Effect of Food 3- Activity Energy Expenditure Basal Metabolism: Required to maintain essential functions to sustain life Needed for chemical reactions in our cells Maintains muscle tone Work done by our heart, lungs, brain, liver, kidneys Depends on active transport of electrolytes and other nutrients in our cells For most, it’s the largest component of total daily energy expenditure Thermal Effect of Food (TEF): Energy needed to digest, absorb and metabolize the nutrients in food Activity Energy Expenditure (AEE): Amount of energy one expends in physical activity daily AEE= most variable component of TEE Fat Free Mass and Basal Metabolic Rate “Low Metabolism” is not a cause of obesity Fat Free Mass (FFM)= total body mass- fat mass High FFM, the higher Basal Metabolic Rate Skeletal Muscle is 3x more metabolicly active than adipose tissue *obeses individuals sit on average 2.25 hours longer than lean individuals A calorie is defined as the energy required to raise 1 gram of water 1 degree Celsius.
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