NUTR 250 Human Nutrition & Metabolisms (PDF)

Dr. Mei Lu, University of Nebraska-Lincoln NUTR 250 Human Nutrition & Metabolisms Chapter 10 Energy Balance, Weight Control and Eating Disorders Dr. Keting Li, FDST, UNL Chapter Topics Energy balance and energy expenditure Body weight and body composition Treatment and prevention of overweight and o...

Dr. Mei Lu, University of Nebraska-Lincoln NUTR 250 Human Nutrition & Metabolisms Chapter 10 Energy Balance, Weight Control and Eating Disorders Dr. Keting Li, FDST, UNL Chapter Topics Energy balance and energy expenditure Body weight and body composition Treatment and prevention of overweight and obesity Weight loss & fad diets Common eating disorders Prevalence of Self-Reported Obesity Among U.S. Adults by CDC 2011 https://www.cdc.gov/obesity/data/prevalence-maps.html 2023 Energy balance Energy equilibrium: Calories consumed = Energy expended Stable weight Energy Intake Energy Expenditure Energy balance Positive energy balance: Negative energy balance: Energy intake > energy expenditure Leads to weight gain Desired in growth stages: Pregnancy, infancy, childhood, adolescence Energy intake < energy expenditure Leads to weight loss Desired in adults when body fat exceeds healthy levels Not recommended during growth stages! Energy Intake Energy Expenditure Energy Intake Energy Expenditure Energy Intake Energy provided by food and beverages Ways to determine food energy: 1. Measure using a bomb calorimeter 2. Estimate using food databases 3. Calculate from energy-providing nutrients (and alcohol) 1 kilocalories equals to the amount of heat needed to raise the temperature of 1 kg of water by 1 oC. Energy Expenditure Basal Metabolism (or Basal metabolic rate, BMR) Minimum energy needed to maintain resting bodily functions in thermo-neutral environment; includes heartbeat, respiration, organ activity Most adults: 60-70% of total expenditure Often referred to as resting metabolism date (RMR) or resting energy expenditure (REE) Thermogenesis TEF Physical Activity BMR It does not include energy expended for physical activity or the digestion, absorption, and processing of nutrients recently consumed. Energy Expenditure Basal Metabolism WHO estimate: For women, 0.9 kcal/kg/h = 21.6 kcal/kg/d For men, 1.0 kcal/kg/h = 24.0 kcal/kg/d What is the basal metabolic rate for a 130 lb women for an entire day? 1lb=0.45kg Thermogenesis TEF Physical Activity BMR Energy Expenditure Basal Metabolism BMR vary among individuals Increased BMR: Greater muscle mass Body temperature Higher than normal secretions of thyroid hormones Aspects of nervous system activity Growth stages of the lifestyle Caffeine and tobacco increase metabolism Recent exercise Decreased BMR: Lower than normal secretions of thyroid hormones Restricted calorie intake Less body surface area and muscle mass Aging after age 30 years Thermogenesis TEF Physical Activity BMR Energy Expenditure Energy for Physical Activity Increase energy expenditure as much as 25-40% of total expenditure Increase in obesity in the US in part due to lack of activity Easy fixes: Stairs vs. elevator Walking vs. driving Standing vs. sitting Thermogenesis TEF Physical Activity BMR Energy Expenditure Thermic Effect of Food (TEF) Energy used to digest, absorb, transport, store, and metabolize the nutrients consumed in the diet 5-10% of energy intake: Varies by food composition: Protein-rich meal: 20-30% Carbohydrate-rich meal: 5-10% Fat-rich meal: 0 to 3% Large meals results in higher TEF than the same amount of food eaten over many hours Thermogenesis TEF Physical Activity BMR Energy Expenditure Thermogenesis The process of heat production Small contribution to TEE Non-voluntary physical activity: Thermogenesis TEF Physical Activity Fidgeting Shivering Maintaining muscle tone Holding body upright Triggers: Extreme cold Overfeeding Trauma Starvation BMR Measuring Energy Expenditure Direct Measurement 1. Direct calorimetry 2. Indirect calorimetry Estimated Energy Requirements based on Height & weight Physical activity level Age Etc. Measuring Energy Expenditure Direct Calorimetry Measure heat release 60% of the energy body uses leaves as heat Measuring Energy Expenditure Direct Calorimetry Measuring Energy Expenditure Indirect Calorimetry 1. Collection of inhaled and expired air: O2 uptake CO2 production O2 consumed + CO2 produced predict the body’s use of energy Measuring Energy Expenditure Estimated Energy Requirements (EERs) Men 19+: EER = 662 - (9.53 x Age) + PA x ([15.91 x WT] + [539.6 x HT]) Women 19+: EER = 354 – (6.91 x Age) + PA x ([9.36 x WT] + [726 x HT]) Online calculator: https://www.omnicalculator.com/health/eer-estimated-energyrequirement Measuring Energy Expenditure Estimated Energy Requirements (EERs) Men 19+: EER = 662 - (9.53 x Age) + PA x ([15.91 x WT] + [539.6 x HT]) A man who is 25 years old, is 1.75m tall and 70 kg, and has an active lifestyle. Calculate the EER for this person. Estimating Body Composition “Old school”: Weight-for-height tables “New school”: Total body fat Location of body fat Weight-related medical problems Body Mass Index (BMI) Weight [kg] (Height [m])2 BMI = WHO Under weight 18.5 Over Obesity Obesity Obesity II weight I III Normal weight 25 30 35 Weight-for-height standard Convenient Applies to both men and women Does not apply to children, teens, older adults, pregnant & lactating women BMI overweight ≠ overfat 40 Visualization of BMI Adams et al., 2006 Body Fat Content Desirable body fat percentage: Men: 8%-24% Women: 21%-31% The further body fatness rises above the desirable levels, the greater the health risks are likely to be Methods for Measuring Body Fat 1. % body fat = (495 / Body density) – 450 Body density = Body Weight / Body Volume Measurement body volume: Underwater weighing Air displacement 2. Skinfold thickness 3. Bioelectrical impedance 4. Dual energy X-ray absorptiometry (DEXA) Measuring body density/volume Underwater weighing Air displacement Bod Pod Measuring body density/volume - Underwater weighing Measuring body density/volume – Bod Pod Measuring Body Fat Content Skinfold thickness: Calipers used to measure subcutaneous fat Multiple sites, arms, abdomen, back Calculate and predict body fat http://www.linear-software.com/online.html Measuring Body Fat Content Bioelectrical impedance: Low-energy electrical current measures electrical resistance Adipose tissue resists electrical flow more than lean tissue. Adipose tissue has less electrolytes and water than lean tissue. Measuring Body Fat Content Bioelectrical impedance: Low-energy electrical current measures electrical resistance Adipose tissue resists electrical flow more than lean tissue. Adipose tissue has less electrolytes and water than lean tissue. Measuring Body Fat Content – Bioimpedance Analysis Measuring Body Fat Content Dual energy X-ray absorptiometry (DEXA): Most accurate method to determine body fat 5-20 min whole body scan DEXA can estimate body fat, fat-free soft tissue, and bone minerals Obesity, osteoporosis can be investigated Measuring Body Fat Content - DEXA Body Fat Distribution Upper body fat distribution Lower body fat distribution (Pear shape) (Apple shape) Android Obesity Associated with: ↑ Cardiovascular disease ↑ Hypertension ↑ Type 2 diabetes Seen in: Males (testosterone) High glycemic load diet High alcohol intake Waist circumference: >40 inches (102 cm) in males >35 inches (88 cm) in females Gynoid Obesity Storage of fat in lower body Smaller abdomen Larger buttocks and thighs Tied to estrogen and progesterone Abdominal fat increases after menopause Factors affecting body weight and composition Genetic predisposition Account for 40 to 70% of weight differences: Body type Metabolic rate Factors that affect hunger and satiety “Thrifty genotype”: Use energy more frugally Store fat more readily Set-Point Theory: Genetically predetermined body weight/fat content Metabolic adaptations to weight loss and gain Factors affecting body weight and composition Environment Genetic predisposition does not explain the rapid rise in obesity in last 50 years Environmental factors affect when, what, and how much we eat → Genetic and environmental synergy Factors affecting body weight and composition Diseases and Disorders Limited fat stores Anorexia nervosa Cancer cachexia Obesity Brain tumors Ovarian cysts Hypothyroidism Terms: Anorexia nervosa, or anorexia, is an eating disorder characterized by low weight, fear of gaining weight, and a strong desire to be thin, resulting in food restriction. Cancer cachexia is characterized by systemic inflammation, negative protein and energy balance, and an involuntary loss of lean body mass. Eating Behavior Regulation Hunger Physiological drive to find and eat food Internal control Appetite Psychological drive to eat External factors Eating Behavior Regulation Hypothalamus integrates internal cues: Blood glucose levels Hormone secretion Sympathetic nervous system Terms: Hypothalamus is a portion of the brain, is the key integration site for the regulation of satiety. Cortex is the outer layer that lies on top of your cerebrum. Your cerebrum is the largest area of your brain Satiety Process 1. 2. 3. 4. 5. Sensory aspects of food Knowledge that food has been eaten Chewing Expansion of stomach and intestines Effects of digestion, absorption, metabolism Excretion of hormone Conscious thinking (taking place in cortex) can override hunger & satiety signals! Treatment of Overweight and Obesity Long-term lifestyle changes A sound weight loss program should include 3 key components 1. control of energy intake 2. regular physical activity 3. control of problem behaviors Commercial weight-loss programs: o Only 5% maintain long-term weight loss o Typically 1/3 of weight loss is regained within 3-5 y Only surgical approaches routinely show success in maintaining the weight loss Control of Energy Intake Adipose tissue (mostly fat) contains about 3500 kcal/lb. To lose 1 pound of adipose tissue per week Energy intake must be decreased ~ 500 kcal/day OR Physical activity must be increased by ~ 500 kcal/day Energy intake goal Women: 1200 kcal/day Men: 1500 kcal/day Energy allowance can be higher for very active people Food choice: less saturated and trans fat, refined carbohydrates Regular Physical Activity More energy is burned during physical activity than at rest 100 – 300 extra kcal/day above and beyond normal daily activity leads to a steady weight loss Duration and regular performance, rather than intensity are the keys to success Example: for a 70 kg person who conducts medium aerobic activity for 1 h 70 kg * 5.0 kcal/hr * 1hr = 350 kcal Control of Problem Behaviors Finishing an ample dinner Sitting in front of your computer Watching a movie ??? ??? ??? ??? Control of Problem Behaviors Modifying problem behaviors Analyzing behavior chains and pinpoint how to change unwanted habits The earlier in the chain that you substitute a nonfood link, the easier it is to stop a chain reactions Intermittent Fasting Intermittent fasting involves alternating cycles of eating and going out food; does not say anything about which foods to eat, but rather when you should eat them. Benefits Boosts working memory Improves blood pressure and resting heart rates Loss weight while maintaining muscle mass Prevents obesity Reduce insulin resistance in people with type 2 diabetes Intermittent Fasting - the 16/8 method A time restricted diet Fixed window of eating 8 hours each day. No food for the remaining 16 hours while water, plain coffee or tea is allowed No calorie restriction – you can eat until you are satisfied each day, as long as you wait 16 hours before eating again Intermittent Fasting - the 5:2 diet During 2 non-consecutive days of the week, eat only about 500800 calories. For the other 5 days of the week, eat as usual and don’t have to think about restricting calories. e.g., fasting on Mon & Wed, consume a “normal” number of calories for the rest five days Keto Diet Low-carbohydrate, fat-rich eating plan that has been used to treat specific medical conditions If you deprive the body of glucose, an alternative fuel called ketones is produced from stored fat (thus, the term “keto”) No “standard” ketogenic diet, typically 70-80% fat, 5-10% carbohydrate and 10-20% protein. For a 2000-calorie diet, this translates to about 165g fat, 40g carbohydrate and 75g protein Treatment of Overweight Modify behaviors, decrease energy intake, increase physical activity Medication Lipase inhibitors: Reduces fat digestion by 30% Drugs that enhance norepinephrine and serotonin activity in the brain Cause neurotransmitter to remain active in brain longer, which suppress of hunger Amphetamine-like medications Appetite-suppressant Treatment of Severe Obesity Severe obesity: weighing at least 100 lb over healthy body weight; professional treatments are required Very-low-calorie-diets (VLCDs): 400-800 kcal/day Half calories are carbohydrate, and the rest is high quality protein 3-4 lb can be lost per week Carefully monitored Surgical procedures (gastroplasty) Recommended for those who have a BMI ≥ 40, have had obesity for at least 5 years Reduce stomach capacity or bypass segment of small intestine Gastroplasty for treating severe obesity Gastroplasty for treating severe obesity Fad Diets Claim miraculous weight loss or improved health often by unhealthy or unrealistic eating plans. How do I spot a fad diet? Promising a quick fix Warnings of danger from single product Claims are too good to be true Simplistic conclusions from complex study Based on single study Lack of peer preview Ignoring differences among individuals or groups Statements refuted by reputable organizations Lists of “good” and “bad” foods Selling a product, often using testimonials Treatment of Underweight Health risks of being underweight (BMI