Study Guides (248,617)
Canada (121,638)
HLTH 230 (28)

Overweight and Obesity (week 11).docx

19 Pages
80 Views

Department
Health Studies
Course Code
HLTH 230
Professor
Jeffery Lalonde

This preview shows pages 1,2,3,4. Sign up to view the full 19 pages of the document.
Description
Over Weight and Obesity 12/24/2012 6:43:00 AM Overweight and Obesity  Energy Balance o When energy in is equal to energy out, a person’s body weight is stable o When energy in is greater than energy out, body weight increases o When energy in is less than energy out, body weight decreases  Excess protein, excess carbohydrates, excess fat, and excess alcohol can lead to increased body fat o Energy goes up and down throughout the day Macronutrient Broken into Carbohydrate Glucose Stored: Glycogen stores Body fat stores Fat Fatty Acids Stored: Body fat stores Protein Amino Acids Stored: Body fat stores Individuals are constantly burning energy, even at rest  Basal metabolic rate We eat to refuel  When the energy we refuel does not equal the energy expended, weight will change o If food intake is 3500 kcal greater than expenditure, we will gain 1 pound of fat  3500kcal = 1 lb gain  Healthy weight adult has energy stores between 50,000 and 200,000 kcal o Only 1500-200 kcal from glycogen, in liver and muscle  If calories are less, regardless of what you eat, you will lose weight o 1 kcal = 4.184 joules o Energy needed to burn 1 kcal o Energy that increases 1g of water by 1 degree  A fast change in body weight is not a change in body fat o Lose 1 litre of water, lose 2 pounds o Glycogen is hydrophilic, holds on to water  Change in the amount of fluid in the body is responsible for rapid weight change Weight loss  Long term weight loss is generally 75% fat and 25% lean tissue o Gradual and slow weight loss o Slight caloric deficit  Starvation / Rapid weight loss o 50% fat and 50% lean tissue o Severe caloric deficit  Fat losses and gains should be gradual Rapid weight loss – yoyo effect  Starved volunteers for 24 days o Loss mass and fat  After refeeding for 12 days eating whatever they want o When they reached 100% normal weight they entered hyperphagia  Eating more than normal  Fat mass and fat free mass after weight loss influences how much a person is going to eat o Put on more weight than initial weight after starvation Basic Chemistry – Energy in  Food and drink provide energy  Calorie content of foods o Burning foods  When food is burned the chemical bonds between carbon and hydrogen break  Releases energy in the form of heat  Measure the amount of heat, will tell you how many calories  Problem  Overstates the amount of energy human body gets from foods  Human body is not that efficient  We do not use all of those calories  Overestimates how many calories are actually used  Indirect calorimetry o Carbon dioxide and water are produced  The amount of oxygen used givens indirect measure of heat produced  Energy of foods can also be calculated by calculating fat, carbohydrate, protein, and alcohol in food o Fat as most energy = 9 kcal o Alcohol has 7 kcal o Carbohydrates and protein have 4 kcal of energy Food Intake Regulation  Appetite o Integrates response to the sight, smell, thought, or taste of food that initiates or delays eating  Can be experienced without hunger  Prompts a person to eat or not eat  Eg. Favourite dessert after a big meal  Sigh and smell triggers appetite, not hunger o You can also be hungry, but no appetite  Eg worried, tired, sick  Hunger o Irritating painful sensation caused by a lack of food o Initiates food seeking behaviour o Triggered by chemical messengers initiating in the brain  Hypothalamus  When you eat, it takes times for nerves in the upper digestive tract to signal the hunger centre in the hypothalamus to turn off o Can be influenced by:  Presence or absence of nutrients in the blood  Size and composition of preceding meal  Whether GI tract has emptied  Climate  Cold increases intake  Heat decreases intake  Customary eating patterns  Routines, other people, holidays  Exercise  Increased need for macronutrients  Hormones  Anorectic hormone (ANOREXIA – WANT WEIGHT LOSS, NOT HUNGRY)  Suppresses appetitive  Promotes weight loss  Promotes negative energy  Orexigenic Hormone  Increasing hunger  Increasing intake  Illness o The stomach is a reservoir which handles periodic amounts of food  Most food has left the stomach after 4 hours  Most people do not feel like eating again until the stomach is empty  Satiation DURING o The feeling of satisfaction and fullness that occurs DURING a meal, halts eating  Determines how much food is consumed at a meal  Receptors in the stomach stretch and the person begins to feel full  Satiation occurs and the person stops eating  Satiety AFTER o The feeling of satisfaction that occurs AFTER a meal o Inhibits eating until next mean  Satiety determines how much time passes between meals  Satiation tells us to stop eating  Satiety tells us not to start eating again  Satiety can be overridden by appetite  Favourite food can cause you to keep eating  Regardless of hunger, people typically over eat when offered an abundance and variety at buffets  Sensory Specific Satiety o We tend to get bored of food as we eat it o The more variety there is, the more likely it will increase over all consumption  Buffet o Pleasantness of food decreases  Satiety can be specific to food  Overriding hunger and satiety o Food cravings when bored o Eat when celebrating o Eat when stressed o Eat more with variety and large portions o Discipline can lead us to ignore hunger o Not eating when excited  Portion size o People tend to eat more when portions are larger  Increase in obesity due to increase in portion sizes  Influences energy intake  Despite increases in intake, those who consume large portions do not report to increased levels of fullness  Eating low energy dense foods (fruits, vegs) maintains satiety while reducing energy intake  Bottomless bowl o People eat more when they think there is more food o Judgment of calories becomes false  Despite addition of food, people did not feel more full Sustaining satiation and satiety  Ability of food to produce satiation and sustain satiety depends on nutrient composition o Protein is the most satiating energy yielding nutrient o Food rich in fibre provides satiation by filling the stomach and delaying gastric emptying  Prolonging satiety o Fructose in sugary fruit drinks may stimulate appetite and increase intake  Fat has a week effect on satiation o High fat foods are flavourful  Increases appetite  Energy dense o Fat provides little satiation during, o Strong satiety after a meal once it reaches intestines  Fat in the intestines triggers release of CCK  Signals satiety o High fat foods must be eaten in small portions compared to fibre fich foods  Portion size correlates with food satiety Hypothalamus  Control centure, message centre o Integrates messages about energy intake o Expenditure and storage from other parts of the brain, mouth, liver, GI tract  Chemicals in the brain participate in appetite control and energy balance o Neuropeptide Y  Favours positive energy balance  Orexigenic  Initiates eating  Causes carb cravings  Decreases energy expended  Increases fat storage o Gastrointenstinal Hormones that regulate food intake  Amylin  CCK  Pancreatic peptide  Etc Energy Out  Breaking down energy yielding nutrients involves work and produced heat o Thermogenesis  Total body energy expenditure o Basal metabolism o Physical activity o Food consumption o Climate  Eg stress, trauma Basal Metabolic Rate  2/3 of the energy expended by an average person per day  Metabolic activities include o Maintaining body temperature o Breathing o Circulation o Making red blood cells, tissues  The rate at which the body expends energy to maintain vital functions when they body is at digestive, physical, and emotional rest o In general, the more a person weights, the greater energy is needed on basal metabolism o The energy expended per pound may be lower  Eg 150 pound adult has a higher metabolic rate than a baby  But the baby has a higher metabolic rate  Growing  Basal metabolic rate is higher in o People who are growing (children, pregnancy) o People with more lean muscle mass  Active tissue o During stress o Hyperthyroidism o Caffeine o Smoking o Environmental temperatures  Body has to do more work  BMR slows down with o Fasting  Body attempts to converse fuel stored o Malnutrition o Age  Declines with age  Sacropenia  Muscle loss due to age  BMR o Rate of energy use for metabolism under specific conditions  After 12 rest  Without physical activity or emotional excitement  Comfortable setting  Resting Metabolic Rate o A measure of energy use of a person at rest in a comfortable setting o Less strict criteria for food intake and physical activity  RMR is usually higher than BMR because it is less prepared for strict conditions Physical Activity  The voluntary movement of the skeletal muscles and support systems  Most variable and changeable component of energy expenditure  Extra energy is required to the move  The heart and lungs require extra energy  How much energy is required will depend on o The persons weight o Muscle mass o The activity being performed  Intensity and duration Thermic Effect of Food  10% of intake  When a person eats, GI tract muscles speed up their activity o Increased energy produces heat o Thermic effect of food  Thermic effect of food is higher for a meal eaten all at once than spread out over a couple of hours o Generally TEF is not counted  No research for negative calorie foods  TEF o Fat 0-5% o Carbohydrate 5-10% o Protein 20-30% o Alcohol 15-20% Adaptive Thermogenesis  Additional energy expenditure when the body is dramatically challenged o Physically conditioning o Extreme cold o Overfeeding o Starvation o Trauma  Body has extra work to do  Uses extra energy to build tissues, making hormones, etc. Alcohol and Appetite  Alcohol (ethanol) has 7kcal  Can decrease lipid oxidation by 70% o Less lipids being broken down  Body usually compensates by decreasing appetite because lipids are not being broken down and enough calories are consumed o Not the case for alcohol  Alcohol can stimulate appetite o Decrease in leptin levels Obesity a
More Less
Unlock Document

Only pages 1,2,3,4 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit