Energy Balance and Body Weight

Chapter 11: Energy Balance and Body Weight

Big Idea

• Health is achievable regardless of body size.

• Rising obesity rates linked to various diseases globally.

Obesity's Effects

• Linked diseases: heart disease, diabetes, cancer, asthma.

• Scientific exploration of causation vs. correlation between obesity and diseases.

• Age-related disease prevalence and its relation to obesity.

Perspectives on Obesity and Health

• Obesity as a Cause:

  • Obesity linked to numerous chronic diseases.

  • Losing weight can potentially prevent diseases.

• Health at Every Size (HAES):

  • Stresses validity of diverse body sizes.

  • Promotes health inclusivity and opposes stigma associated with weight.

  HAES Principles:

  1. Weight inclusivity: Respect diverse body shapes.

  2. Health enhancement: Improve overall wellbeing beyond weight.

  3. Eating for well-being: Focus on nutritional needs and pleasure over weight.

  4. Respectful care: Combat weight bias and stigma.

  5. Life-enhancing movement: Encourage physical activity for all.

Obesogenic Environment

• Defined by CDC as environments promoting unhealthy food intake and physical inactivity.

• NHANES report indicated increased obesity rates in the US since 1980.

Assessment of Body Weight and Fatness

Key Learning Objectives:

1. Calculate BMI based on weight and height.

2. Discuss BMI limitations.

3. Understand factors affecting body fat distribution.

BMI Definition and Calculation

• Body Mass Index (BMI): Weight in relation to height.

• Categories:

  • Underweight: BMI < 18.5

  • Normal weight: BMI 18.5-24.9

  • Overweight: BMI 25-29.9

  • Obesity: BMI ≥ 30

• Calculation: BMI = [weight (lb) × 703] / [height (in)²]

Limitations of BMI

• Does not account for fat distribution and composition.

• Underestimates fat in muscular individuals and vice versa.

• Was developed based on limited demographic populations.

Body Fat Measurement

• Different methods for assessing body fat:

  1. Skin-fold tests: Measure fat thickness.

  2. Underwater weighing: Measures density to assess body composition.

  3. Bioelectric Impedance Analysis (BIA): Uses electrical resistance to estimate fat.

  4. Dual-energy X-ray absorptiometry: Measures bone density and body fat.

Fat Distribution and Health Risks

• Visceral fat (around organs) is more harmful than subcutaneous fat.

• Waist circumference measurement: critical indicator of health risk.

  • Men > 40 inches, Women > 35 inches at risk of diseases.

• Waist-to-hip ratio: better predictor of chronic disease than BMI.

Energy Balance

Key Learning Objectives:

1. Define basal metabolism and its affecting factors.

2. Explore weight maintenance theories.

3. Recognize appetite control complexities.

Concept of Energy Balance

• Energy balance: Intake = Expenditure.

• Positive: Excess energy stored.

• Negative: Body uses stored energy.

Estimating Energy Needs

• Estimated Energy Requirement (EER):

  • Formula considers age, sex, weight, height, and activity.

  • Physical Activity Categories: Sedentary, low active, active, very active.

• EER Formulas:

  • Men: EER = 662 - (9.53 × age) + PA × (15.91 × wt + 539.6 × ht)

  • Women: EER = 354 - (6.91 × age) + PA × (9.36 × wt + 726 × ht)

Total Energy Expenditure (TEE)

• TEE includes basal metabolic rate, energy from food digestion, and physical activity.

Factors Affecting Energy Intake and Expenditure

• Physiological and Genetic Influences:

  • Genetics affect hunger and satiety.

  • The hypothalamus regulates appetite.

• Psychological and Behavioral Influences:

  • Emotional states can dictate eating patterns.

  • Societal norms influence dietary habits.

Health Recommendations

1. Dietary Changes:

   • Nutrient-dense foods, variety from food groups.

   • Portion control.

2. Physical Activity:

   • Move more: Minimum of 150 minutes of moderate-intensity aerobic activity weekly.

   • Muscle-strengthening activities at least two days a week.

Conclusion

• Emphasize health-focused approaches rather than weight-centric.

• Encourage physical activity and balanced diets for all individuals regardless of body size to improve overall health outcomes.

Big Idea

• Health is achievable regardless of body size, highlighting the importance of focusing on overall well-being instead of solely body weight.

• Rising obesity rates are linked to various diseases globally, stressing the need for comprehensive health approaches.

Obesity's Effects

• Linked diseases include heart disease, diabetes, cancer, and asthma, significantly impacting health outcomes.

• Scientific exploration investigates the causation versus correlation between obesity and the prevalence of these diseases, emphasizing the multifactorial nature of health.

• Age-related disease prevalence is intricately connected to obesity, with varying impacts across different age groups.

Perspectives on Obesity and Health

• Obesity as a Cause:

  • Obesity is linked to numerous chronic diseases that can adversely affect quality of life.

  • Losing weight may potentially prevent the onset of diseases, though individual responses vary widely.

• Health at Every Size (HAES):

  • This approach stresses the validity of diverse body sizes and promotes health inclusivity.

  • HAES opposes stigma associated with weight, advocating for acceptance and understanding.

  HAES Principles:

  1. Weight inclusivity: Respect and embrace diverse body shapes and sizes.

  2. Health enhancement: Focus on improving overall well-being and quality of life beyond weight alone.

  3. Eating for well-being: Prioritize nutritional needs and the pleasure of food over restrictive diets aimed solely at weight loss.

  4. Respectful care: Actively combat weight bias and discrimination in healthcare and other areas.

  5. Life-enhancing movement: Encourage all individuals to engage in physical activity that promotes enjoyment and improves health, regardless of body size.

Obesogenic Environment

• Defined by the CDC as environments that facilitate unhealthy food intake and discourage physical activity, contributing to rising obesity rates.

• The NHANES report indicates a significant increase in obesity rates in the US since 1980, prompting public health concerns and interventions.

Assessment of Body Weight and Fatness

Key Learning Objectives:

1. Calculate BMI based on weight and height.

2. Discuss BMI limitations and applicability.

3. **Understand factors affecting body fat distribution.

BMI Definition and Calculation

• Body Mass Index (BMI): A formula that relates weight to height to categorize individuals.

• Categories include:

  • Underweight: BMI < 18.5

  • Normal weight: BMI 18.5-24.9

  • Overweight: BMI 25-29.9

  • Obesity: BMI ≥ 30

• Calculation: BMI = [weight (lb) × 703] / [height (in)²]

Limitations of BMI

• BMI does not account for factors such as fat distribution and body composition, potentially misleading weight status evaluations.

• It tends to underestimate body fat in muscular individuals and overestimate it in those who are less muscular.

• The BMI formula was developed based on limited demographic data and may not represent all populations accurately.

Body Fat Measurement

• Several methods are available for assessing body fat, including:

  1. Skin-fold tests: Measure fat thickness using calipers at various body sites to estimate overall body fat percentage.

  2. Underwater weighing: Measures body density by comparing underwater weight to surface weight.

  3. Bioelectric Impedance Analysis (BIA): Uses electrical resistance to provide estimates of total body fat based on the amount of water in the body.

  4. Dual-energy X-ray absorptiometry (DEXA): A highly accurate method that measures bone density and body fat distribution using low-dose X-ray technology.

Fat Distribution and Health Risks

• Visceral fat, located around internal organs, is more harmful compared to subcutaneous fat stored just beneath the skin.

• Waist circumference measurement serves as a critical indicator of metabolic health and disease risk:

  • Men with waist measurements greater than 40 inches and women with waist measurements over 35 inches are at increased risk for health complications.

• Waist-to-hip ratio is noted to be a better predictor of chronic disease than BMI alone, particularly for cardiovascular conditions.

Energy Balance

Key Learning Objectives:

1. Define basal metabolism and identify its influencing factors.

2. Explore theories related to weight maintenance and regulation.

3. **Recognize the complexities of appetite control and its regulation.

Concept of Energy Balance

• Energy balance is defined as the relationship between caloric intake and energy expenditure in the body.

  • Positive energy balance: Indicates surplus energy that is stored as fat in the body.

  • Negative energy balance: Occurs when the body uses stored energy for activation, leading to weight loss.

Estimating Energy Needs

• Estimated Energy Requirement (EER): Calculated using specific formulas that consider factors like age, sex, weight, height, and physical activity level (PAL).

  • Physical Activity Categories: Include Sedentary (little or no exercise), Low Active (light exercise), Active (moderate exercise), and Very Active (hard exercise).

• EER Formulas:

  • Men: EER = 662 - (9.53 × age) + PA × (15.91 × wt + 539.6 × ht)

  • Women: EER = 354 - (6.91 × age) + PA × (9.36 × wt + 726 × ht)

Total Energy Expenditure (TEE)

• TEE accounts for total energy expended in a day, including basal metabolic rate (BMR), thermic effect of food (TEF), and energy used during physical activity.

Factors Affecting Energy Intake and Expenditure

• Physiological and Genetic Influences:

  • Genetics can significantly influence hunger levels and satiety signals in the body, affecting dietary choices.

  • The hypothalamus plays a central role in regulating appetite through hormones such as ghrelin and leptin.

• Psychological and Behavioral Influences:

  • Emotional states, such as stress and depression, can dictate eating patterns, often leading to overeating or unhealthy food choices.

  • Societal norms and cultural influences can shape dietary habits and perceptions around body image.

Health Recommendations

1. Dietary Changes:

   • Focus on consuming nutrient-dense foods while ensuring diversity across food groups.

   • Practice portion control to prevent excessive caloric intake.

2. Physical Activity:

   • Aim for a minimum of 150 minutes of moderate-intensity aerobic activity weekly, alongside muscle-strengthening activities at least two days a week to promote overall health and weight management.

Conclusion

• It is essential to emphasize health-focused strategies rather than weight-centric approaches when discussing body weight and health.