4 - Chapter_4_Weight_Management

HSS 1101 - Determinants of Health

• Course offered by the University of Ottawa

CORE CONCEPTS IN HEALTH

• Chapter 4: Weight Management

  • Prepared by: Dave Kato, MacEwan University

  • Edition: Fourth Canadian Edition

  • Authors: Irwin, Burke, Insel, Roth

Prevalence of Adult Obesity in Canada

• Figure 4.1: Comparison of adult obesity rates by province (2004, 2005, 2015)

• Self-reported vs. measured heights and weights

Body Composition and Energy Balance

Body Composition

• Divided into:

  • Fat-Free Mass: Includes water, glycogen, muscle, and connective tissues

  • Body Fat Types: Subcutaneous and Visceral

Energy Balance

• Critical for maintaining a healthy weight

• Positive energy balance: more energy intake than expenditure

• Negative energy balance: more energy expenditure than intake

• Factors influencing energy expenditure:

  • Decreased physical activity

  • Increased sedentary behavior (screen time, video games)

Evaluating Body Weight and Body Composition

Body Mass Index (BMI)

• Relationship between height and weight

• Used in conjunction with other measures for health risk assessment

• Limitations: Does not distinguish fat from fat-free mass; inaccurate for muscular or shorter individuals

Body Composition Analysis Methods

1. Hydrostatic Weighing & Bod Pod:

   • Hydrostatic weighing: accurate body fat estimate using water

   • Bod Pod: uses air displacement to measure body fat

2. Circumference Measures:

   • Waist circumference: key indicator of abdominal obesity

   • Measurements: >40 in (102 cm) for men; >35 in (88 cm) for women increase chronic disease risk

   • Waist-to-hip ratios: >0.94 for men, >0.82 for women linked to heart disease and diabetes

3. Bioelectrical Impedance:

   • Uses electrical current to differentiate between fat mass and fat-free mass

4. Scanning Procedures:

   • Accurate but expensive methods include DEXA, CAT scan, and MRI

Health Risks of Excess Body Fat

• Increases mortality rate and impacts life expectancy

• Obesity contributes to various health issues:

  • Elevated cholesterol and triglycerides

  • Cardiovascular disease (CVD) risks

  • Other risks include hypertension, impaired immune function, skin problems, and mental health issues

• Link between obesity and diabetes: kidney failure, nerve damage, and increased risks of stroke

Body Fat Distribution

• Men typically store fat in the upper body (apple shape)

• Women often gain fat in the hips/thighs (pear shape)

• Weight drops of 5-10% yield significant health benefits

• Waist circumference measurements correlate with metabolic syndrome risks

Problems With Very Low Body Fat

• Extremely low body fat levels pose health risks:

  • Reproductive, circulatory, and immune disorders

  • Muscle wasting and fatigue

  • Potential development of eating disorders (e.g., Female Athlete Triad)

Body Mass Index (BMI) Classification and Associated Risks

• A table outlining BMI classes in relation to waist circumferences, identifying health risks associated with each class

Metabolism

• Crucial in regulating body fat and weight

• Resting Metabolic Rate (RMR): major energy expenditure component

  • Males typically have a higher RMR due to muscle mass

• Exercise, particularly resistance training, can help maintain or increase RMR

Hormonal Influences on Body Fat

• Hormones (e.g., leptin, ghrelin) regulate body weight and fat storage

• Leptin: signals fat stores to the brain

• Ghrelin: stimulates appetite

Lifestyle Factors

• Obesity rates influenced by factors beyond genetics:

  • Overeating, sedentary lifestyle, inadequate sleep

  • Increasing consumption of high-calorie, low-nutrient foods

Obesogenic Environment

• Environments that promote overconsumption and discourage physical activity

• Factors include socioeconomic influences, food marketing, and accessibility

Psychosocial Factors

• Emotional eating as a coping mechanism for stress and negative emotions

• Links between obesity and socioeconomic status

Diet and Eating Habits

• Diet = daily food choices

• Strategies for healthy eating focus on caloric density, portion control, and activity levels

Commercial Weight Loss Programs

• Often include group support, nutrition education, and behavior modification strategies

• Popular options like Weight Watchers require commitment to maintain weight loss

Body Image Issues

Negative Body Image

• Refers to dissatisfaction with one’s body

• Leads to psychological problems and disordered eating behaviors

Eating Disorders

• Anorexia Nervosa:

  • Affects ~1% of population, mostly females

  • Intense fear of gaining weight and compulsive behaviors to avoid eating

• Bulimia Nervosa:

  • Involves binge eating followed by purging behaviors

  • Commonly starts in adolescence, primarily affects women

• Binge Eating Disorder:

  • Characterized by uncontrollable eating and feelings of guilt

  • Associated with higher rates of depression and anxiety

Treatment of Eating Disorders

• Professional help needed to address the psychological aspects of eating disorders

• Anorexia: focus on restoring weight

• Bulimia: stabilizing eating patterns is crucial