Obesity Notes

Chapter 9: Obesity

Introduction

• Overview of obesity as a significant health issue.

1. Metabolic Flexibility

• Definition: Ability of the body to adapt its substrate usage for fuel based on availability and energy demands.

• Important to transition between fats and carbohydrates efficiently, especially during physical activities.

2. Scope of Obesity-Related Health Issues

• Rising prevalence across various populations, with increasing rates of extreme obesity.

• Direct health costs projected to reach approximately $283 billion by 2023, rising to $526.5 billion by 2033. Total projected costs over a decade are around $4.1 trillion.

• Associated with numerous health conditions and raises significant societal costs.

3. Body Mass Index (BMI)

• Definition: A measure used to categorize individuals based on weight relative to height.

  • Formula: BMI = weight (kg) / height (m)^2.

• Cutoffs:

  • Overweight: BMI 25-29.9

  • Obesity: BMI ≥30

  • Useful alongside Waist:Hip ratio and body composition to assess disease risk.

• Waist circumferences indicating risk:

  • Men: ≥40 in (100 cm)

  • Women: ≥35 in (88 cm)

4. Metabolic Profile and Visceral Fat

• Explains the differences in metabolic profiles for individuals with varying amounts of visceral fat.

• Individuals with lower amounts of visceral fat generally have healthier metabolic profiles, including:

  • Lower triglycerides

  • Higher HDL cholesterol

  • Better insulin sensitivity

• Higher visceral fat correlates with negative health outcomes and higher risk for metabolic syndrome.

5. Pathophysiology of Obesity

• Energy Balance: Positive energy balance leads to weight gain, detailed by 3500 kcal = 1 lb of fat.

• Various factors include:

  • Physiological factors (e.g. hunger hormones)

  • Genetic predisposition

  • Set-point theory refers to body weight regulation mechanisms.

• Role of insulin resistance: it leads to disrupted metabolism and storage.

6. Treatment Options for Obesity

• Multiple approaches to weight management include:

  • Dietary changes

  • Behavioral therapy

  • Exercise therapy

  • Pharmacotherapy

  • Surgical options (e.g. bariatric surgery)

• Aim is to achieve safe weight loss, usually 1-2 lbs per week.

7. FITT-VP for Individuals with Obesity

• FITT-VP Components:

  • Frequency: How often one exercises

  • Intensity: Level of exertion during activity

  • Time: Duration of exercise sessions

  • Type: Variety of exercises such as aerobic, resistance, and flexibility.

• Special considerations needed for each exercise type in obese populations.

8. Clinical Considerations

• Signs and Symptoms: Fatigue, dyspnea, movement difficulties.

• Assessment: Regular check-ups for physical factors and readiness for change in weight management.

• Understanding psychological factors such as anxiety regarding exercise.

9. Hormonal Influence in Obesity

• Insulin: Promotes glucose absorption and storage; resistance develops in obesity leading to increased adipose tissue.

• Leptin: Regulates hunger, associated with sustained energy storage but becomes less effective in obesity.

• Ghrelin: Increases hunger; elevated during weight loss, complicating maintenance.

• Dopamine: Affects reward behaviors; deficiency in obese individuals varies food intake patterns.

10. Associated Risks of Obesity

• Increases risks for:

  • Type 2 diabetes

  • Heart disease

  • Hypertension

  • Cancer

  • Other chronic diseases.

11. Conclusion

• Emphasis on behavioral modification and exercise as foundations for weight management.

• Importance of trained clinical exercise physiologists in treating obesity.