NUT 1004 Energy Balance and Weight Control Lecture 8 PDF

1 Energy Balance and Weight Control Kemar Bundy MSc., MPH, PhD(c) NUT 1004 University of Technology, Jamaica  Learning Outcomes List the components of body composition. Explain how to calculate BMI and measure...

1 Energy Balance and Weight Control Kemar Bundy MSc., MPH, PhD(c) NUT 1004 University of Technology, Jamaica  Learning Outcomes List the components of body composition. Explain how to calculate BMI and measure waist circumference and usefulness of this information in regard to a person’s health. Describe the various ways body fat is measured and the pros and c of each method. Define basal metabolism and describe factors that influence the b metabolic rate. Discuss the three major ways the body uses energy. ©McGraw-Hill Education  Learning Outcomes Identify factors that can influence the development of excess body fat. Identify four key elements that are important for weight loss and maintenance. Describe features of reliable weight-loss plans or programs. Discuss ways to gain weight safely and sensibly. Explain the difference between having an eating disorder and practicing disordered eating. ©McGraw-Hill Education How to classify overweight and obesit Body Mass Index (BMI) Body Mass Index (BMI): numerical value that reflects body weight adjusted for height Weight (kg)/height (m2) Weight (lb)/[height (in)]2 x 703 About Adult BMI BMI Weight Status Below 18.5 Underweight 18.5- 24.9 Normal or Healthy Weight 25.0- 29.9 Overweight 30.0 and above Obese How is BMI interpreted for adults? Centers for Disease Control and Prevention. Accessed February 6, 2021. ©McGraw-Hill Education  Measuring Waist Circumference Waist circumference is a quick and easy way to determine obesity-related risk. Desirable circumferences: Men < 40 inches (101.6 cm) Women < 35 inches (88.9 cm) Source: RJL System ©McGraw-Hill Education  Excess Body Fat: Effects on Healt People with BMI’s > 25 have increased risk for type 2 diabetes, hypertension, CVD, and osteoarthritis. People with BMIs > 30 have increased risk of: - Many types of cancer - Complications during and after surgery - More likely to die prematurely, especially extremely obese people - Chronic heartburn, sleep apnea - Fertility problems, i.e., polycystic ovary syndrome - Gestational diabetes - Poor mental health and low self-esteem 7 ©McGraw-Hill Education Excess Body Fat: Effects on Hea Distribution of excess body fat is more closely associated with obesity- related diseases than the percentage of total body fat. Central-body obesity is characterized by excessive abdominal (visceral) fat. Central-body fat distribution is more associated with increased risk for cardiovascular disease and type 2 diabetes than lower- body fat distribution. ©McGraw-Hill Education  Body Composition Two major components: Fat-free mass: Body water, mineral-rich tissues, and protein-rich tissues Total body fat: Adipose tissue Essential fat in cell membranes, certain bones, and nervous tissue ©McGraw-Hill Education  Adipose Tissue All cells contain some lipids, but adipose cells store energy in a droplet of fat. Adipose cells are in: Subcutaneous fat Helps insulate Protects muscles and bones from injury More in women than men Visceral fat In the omentum More in men than women ©McGraw-Hill Education How is Body Composition Measured Underwater Weighing: Dual-Energy X-Ray Absorptiometry (DXA) Air Displacement Bioelectrical Impedance Skinfold Thickness ©McGraw-Hill Education  Underwater Weighing Underwater weighing Compares weight on land to weight when completely submerged in a tank of water Very accurate Problems: inconvenient, expensive, and impractical Figure 10.4 ©David Madison, Photographer’s Choice/Getty Im ©McGraw-Hill Education  Dual-Energy X-Ray Absorptiometry (DX Uses multiple low-energy x-rays to scan body Provides detailed “picture” of internal structures Problems: Very expensive and not widely available outside of clinical settings Source: Photo Courtesy of Hologic, ©McGraw-Hill Education  Air Displacement Assesses body volume: Subject sits in BOD POD chamber Measures air in the chamber with a person in it compared to the volume of air in the chamber without the person Accurate, but the equipment is expensive and not practical to use. Figure 10.6 ©Mary Dean Coleman-Ke ©McGraw-Hill Education  Bioelectrical Impedance Measures conduction of a weak electrical current through the body. Problems: Method can be reliable, if body hydration status is normal. Scientific data about accuracy of devices designed for home use are lacking. Source: RJL System ©McGraw-Hill Education  Bioelectrical Impedance Painless, low-energy electrical current sent through body Greater electrical resistance equals more adipose tissue Adipose tissue contains less electrolytes and water 3% to 4% error margin Source: RJL System ©McGraw-Hill Education  Skinfold Thickness Skinfold thickness is measured at multiple body sites by a trained person. Benefits: Relatively easy and inexpensive to perform. Problems: May underestimate total body fat on overfat people. ©Danielle Goo ©McGraw-Hill Education  Adult Classifications for Percentages of Body Fat Classification Body Fat% Body Fat% Males Females Healthy 13 to 21% 23 to 31% Overweight 22 to 25% 32 to 37% Obese 26 to 31% 38 to 42% Extremely Obese 32% or more 43% or more ©McGraw-Hill Education  Body Fat Content Desirable amounts of body fat: ▪ Men: 8% to 24% - over 24% considered obese ▪ Women: 21% to 35% - over 35% considered obese - Need more body fat because of reproductive functions ©McGraw-Hill Education  Biological Fuels “Biological fuels” are macronutrients in foods and beverages. The body uses a mixture of macronutrients for energy - Glucose and fatty acids are the main fuels. - Small amounts of amino acids are also metabolized for energy. - Alcohol, which is not a nutrient, also provides energy. About 40% of the energy in macronutrients is captured in the molecule ATP. Most of the energy is released as heat. ©McGraw-Hill Education  Energy Intake Figure 10.9a ©McGraw-Hill Education  Energy Output Figure 10.9b ©McGraw-Hill Education  Energy Expenditure Energy output or expenditure: Energy cells use to carry out activities. Basal and resting metabolism Physical activity - Includes NEAT Thermic effect of food (TEF) ©McGraw-Hill Education  Basal and Resting Metabolism Metabolism: Sum of all chemical changes or reactions that constantly occur in living cells Anabolic reactions require energy. Catabolic reactions release energy. Minimal number Basal of calories used for vital physiological metabolism: activities after fasting and resting for 12 hrs. Resting metabolism is slightly higher. Estimating calories for basal metabolism: Rule of thumb: Men: 1.0 kcal/kg/hr; Women 0.9 kcal/kg/hr ©McGraw-Hill Education  Metabolic Rate Influencing factors: Thyroid hormone Body composition Sex (male versus female) Body surface area Age Calorie intake Fever Stimulant drugs Pregnancy and lactation Recovery after exercise ©McGraw-Hill Education  Basal metabolic rate (BMR) Influencing factors: 26 ©McGraw-Hill Education  Energy for Physical Activity Physical activity increases energy needs above basal energy needs Voluntary skeletal muscle movements: Person can easily alter (increase or decrease) Caloric expenditure depends on: Type of activity Duration Intensity Weight of the person Non-exercise activity thermogenesis (NEAT) Involuntary skeletal muscle movements ©McGraw-Hill Education  Thermic Effect of Food (TEF) Energy used to: digest foods and beverages absorb nutrients process the nutrients Putting It All Together To estimate daily energy needs, add together energy (kcal) used for: Basal metabolism (BM) Physical activity (PA) Thermic effect of food (TEF) ©McGraw-Hill Education EER= (BMR x PAL) + TEFTEF PAL) is 10% of (BMR +  Energy Balance Figure 10.11 ©McGraw-Hill Education Body’s Energy States ©McGraw-Hill Education Obesity: Contributing Factors Hormones and peptides that regulate hunger: Ghrelin — hormone, secreted mainly by stomach, that increase eating behavior Leptin — hormone, secreted by adipose cells, that reduces hunger and inhibits fat storage in the body CCK — hormone secreted by small intestine that reduces hunger PYY — peptide secreted by intestines that reduces hunger ©McGraw-Hill Education Obesity: Contributing Factors Hunger vs. satiety: Hunger: uncomfortable feeling leading to a desire to eat Satiety: sense that enough food was eaten ©McGraw-Hill Education  Food Composition Factors High-fat diets associated with excess kcal intakes and increasing obesity rates Fatty foods often contain high amounts of added sugars High-fructose intakes associated Fructose: with weight gain Does not contribute to satiety Increases fatty acid synthesis Homeostasis of Blood Glucose ©McGraw-Hill Education  Genetic Factors Inherited characteristics that influence weight include: Metabolic rate - “Thrifty metabolism” Hormone production Body frame size Pattern of fat distribution What is the set-point theory? Scientific notion that body fat content is genetically predetermined. Difficult to change ©McGraw-Hill Education  Other Factors Environment Food advertising influences appetite Increased portion sizes - CDC Infographics Conditions that reduce a person’s physical activity Mood Self-esteem Emotions Societal pressure ©McGraw-Hill Education Weight Loss and Its Maintenance Determine whether weight loss is needed. Set reasonable and realistic goals. Follow a safe and reliable weight loss plan (see key features of such plans in Table 10.6.) Success depends on: Motivation Calorie intake reduction Regular physical activity Behavior modification A pound of body fat contains about ________ kcal. ©McGraw-Hill Education  National Weight Control Registry Based on members of the National Weight Control Registry successful weight loss and maintenance involves: Eating low-calorie, low-fat diets. Eating breakfast every day. Weighing at least once a week. Exercising on average for 60 minutes each day. Limiting television watching to less than 10 hours per week. ©McGraw-Hill Education  Medical Treatments for Obesity Surgery reduces size of stomach, limiting the Weight-loss medications: Few drugs have FDA approval for long-term weight loss. Bariatric surgery: Often effective for treating obesity - limit amount of food that can be eaten. Figure 10.18a, 10.18b Figure 10.19 ©McGraw-Hill Education  Characteristics of Fad Weight Loss Diets Offers a “quick fix” with rapid weight loss Limits food selections to a few food groups Requires buying a book or various gimmicks, such as supplements (see Table 10.7) Promoters use outlandish and unscientific claims to support its usefulness Relies on testimonials of famous people Does not emphasize the need to change eating habits and physical activity patterns. ©McGraw-Hill Education  Weight Loss Supplements: Evaluating the Hype Be wary of claims that the supplement: Causes rapid and extreme weight loss Requires no need to change dietary patterns or physical activity Results in permanent weight loss Is scientifically proven or doctor endorsed Includes a money-back guarantee Is safe or natural Is supported by satisfied customers Relies on before-and-after photos as “proof” of effectiveness ©McGraw-Hill Education  Underweight: Need to Gain Weight Factors contributing to underweight: Genetics, lifestyle practices, chronic diseases, psychological disturbances Chronic diseases, such as cancer, TB, AIDS, or inflammatory bowel disease, are associated with severe weight loss. To gain weight: Add calorie-dense healthy foods, such as fatty fish like salmon, olives, avocados, seeds, nuts, nut butters, or granola, to diet. ©McGraw-Hill Education  Eating Disorders Risk factors include: Genetic and biological factors Psychological and personality factors Occupation Lifestyle choices being teased about one's weight being female See Table 10.8 for specific risk factors. ©McGraw-Hill Education  Treating Eating Disorders and Disordered Eating Practices 1 A multidisciplinary group of experts in nutrition, mental health, and medicine is necessary for optimal treatment. Treatment should include psychotherapy and address critical nutritional needs and other medical conditions. Registered dietitian nutritionists play a critical role in assessing and treating eating disorders, including providing nutritional counseling. ©McGraw-Hill Education  Treating Eating Disorders and Disordered Eating Practices 2 Treatment can occur in inpatient hospitalization or a in a residential facility that specializes in treatment of eating disorders. Treatment most often occurs in outpatient care settings. May require prescription medications Cognitive behavioral therapy (CBT) is a major treatment approach for BN and BED. CBT teaches people healthy coping strategies to use when under stress. ©McGraw-Hill Education  Summary Body composition includes fat-free mass and total body fat. Body Composition can be measured by various ways with the pros and cons of each method. The body uses a mixture of macronutrients for energy. Most of the energy is released as heat. Energy output or expenditure includes basal and resting metabolism, physical activity, and thermic effect of food. Energy balance considers energy intake and energy output. Question ？ ©McGraw-Hill Education  Summary Multiple factors can influence the development of excess body fat, such as hunger, satiety, hormones, food composition factors. genetic factors, environment, mood... It's important to identify key elements that affect weight loss and maintenance. Weight Loss and its maintenance depends on a safe and reliable weight loss plan. Eating disorders: Psychological disturbances that lead to certain physiological changes and serious health complications. Disordered eating: Chaotic and abnormal food-related practices (usually temporary). Question ？ ©McGraw-Hill Education Thank you ! ©McGraw-Hill Education