NUTR 202 1nd Edition Lecture 17Ch 9 Millions of people in the US are overweight and obese (68% Adults, ~1/3 of children) Greater risk: Minorities, low-income, southern regions.Health and socio-economical consequences: many chronic diseases & psychological problems (costly and results in death). Obesity represents a Global Epidemic. Obesity has been shown to increase the risk of heart attack by 60-80% Over 80% of people with type 2 diabetes are obese.Good news…research has indicated that modest weight loss of 5-10% can reduce the risk of heart diseases and type 2 diabetes. Health weight: weight that minimizes health risks. Not a single number. It's a healthy lifestyle.Weight Management: Means maintaining your weight within a healthy range to reduce your risk for specific health problems. Being overweight, obese or underweight can be unhealthy. Body mass index: Relative weight for height BMI = weight (kg)/ height (m)2Health-related classifications: Healthy weight: 18.5-24.9, more than 25 is overweight, and over30 = obese.Body Composition is the relative amt of fat and lean body mass (some fat is essential). Excess fatincreases risk of chronic health problems; depends on location of excess fat. Apple (abdominal area, most likely males) vs Pear shape.Normal levels of fat mass: Men= 8-19% Women= 21-32% Changes occur as we age:ß lean body mass, ß fat massSubcutaneous fat:  Adipose tissue under the skin, for example, in hips and legs  Pear shape- does not increase health risk as much as excessive visceral fatThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Visceral fat:  Adipose tissue around abdominal organs  Apple shape (central obesity) More metabolically active  Associated with higher disease riskHealthy Weight! Rather than a single number it is a range of weight that is appropriate for your: Gender, height, muscle mass, weight you feel energetic & fit.Healthy weight: Weight that minimizes health risk- REALISTIC!BMI: Relative Weigh for HeightBody composition: Relative amounts of fat and fat-free/lean tissues (bone, muscle, internal organs)Visceral fat versus Subcutaneous fat Visceral fat= Around organs=Central Obesity=Apple Shape Subcutaneous fat=Below the Skin= Fat Sandwich=Pear ShapeAssessing Weight and Body composition: #1 BMI: Easiest to determine if one’s weight is at a healthy level but not accurate for everybody since it does not measure fat % BMI classifications (Learn your numbers) # 2 Skin-fold measurements: % of Fat Because more than 50% of body fat is subcutaneous fat. Bio-electrical impedance may be preferred.  #3 Waist-circumference=Location of Fat Indicator of whether the body distribution is unhealthy.  Other Laboratory Measures: $$$$, not easily available.KNOW THESE:Healthy BMI: Between 18.5-24.99Healthy % Fat Mass: ** Athletes is different!. Men: 8-19% (**5-13%). Women: 21-32% (**12-22%)Healthy Waist Circumference: Men: <40 inches (102 cm). Women: <35 inches (88 cm).Energy Balance: Kcal in (consumption)=Kcal out (expenditure). Imbalance will result in a changein body weight. Positive Energy Balance - Increased Body Fat Stores= Increased appetite+ increased energy intake+ increased fat synthesis.Negative Energy balance - Decreased Body Fat Stores= Increased energy expenditure + increased fat breakdown.Why are we gaining weight? Energy (or Calorie) intake > energy (Calories) burned Eating more Hunger vs appetite Food readily available Portion sizes Inexpensive, unhealthy food Advertisements- fast food Moving less Less active during leisure time Kids less active Labor saving devicesBody stores excess calories: small amt stored as glycogen in liver and sk. musc. If it is too much: Remainder stored as fat in adipocytes.Output: basal metabolism, thermic effect of food, and PA. Review of E intake: Carbohydrate: 4 calories/gram (45-65%0Fat: 9 calories/gram (20-30%)Protein: 4 calories/gram (10-35%)Alcohol: 7 calories/gramEstimated energy requirement (EER): number of calories needed for a healthy individual to maintain his or her weight.Calculated based on gender, height, age, weight, physical activity level, and life stage.***TEE: Total Energy Expenditure is sum of: 1. Basal metabolism or Basal Metabolic Rate (BMR) ~50- 70% of TEE Energy required for life-sustaining functions=Awaked resting body/no digestion (don't eat for 12 hrs) 2. Physical activity (PA) Planned exercise Non-exercise activity thermogenesis (NEAT) Non-planned exercise activities throughout the day3. Thermic Effect of Food (TEF)- if eat 2,000 caloires  10% will go (200 calories) ~10% of TEEDigestion, absorption, metabolism, and storage of nutrientsOn an average person 50-70% or the majority of the total energy expenditure is for the BMR Genetics (75%) Environmental Factors: Lifestyle (external) and Hormones (internal cues)Genetic predisposition to be overweight, BUT eat right & exercise regularly  healthy weightGenetic tendency to be healthy weight, BUT excess calorie & little/no exercise  OverweightHormones (internal cues) Peptide YY: Short-term: intestine ® satiety Ghrelin: Increases=Short-term: stomach ® hungerLeptin=Long-term: adipocytes ® satietyST: Ghrelin released by the stomach increases hunger/appetite at usual mealtimes. PYY reduces hunger/appetite and is released by the distended GI tract after a meal in proportion to the number of calories consumed to reduce appetite.LT Reg is Leptin - RECEPTORS in BRAIN. Leptin is secreted in our fat tissue. Healthy body fat ranges: leptin sends signal to CNS you are SATISFIED.Leptin & Obesity: eat so many CHO’s, that leptin becomes resistant: morbidly obese - wont havehormone  if start to incorporate hormone  control weight. But if more fat tissue  overproduction of leptin  will become resistant and cells of CNS won’t accept the signal  can’t control weight.Factors contributing to obesity: Psychological response with food (eating for comfort or stress), hormonal controls altered (Ex: reduced response to leptin), genetics (Asians thinner), “efficient at using E and storing fat”, lack of PA. For most people, a loss of 5% to 15% of body weight will significantly reduce disease risk-eat less, exercise more, or bothTraditional theory: 1lb fat= 3500 calories To lose a 1lb/week, decrease