Nutrition material 13

Tristan is a talented mathematician who faces pressure due to his weight despite leading a healthy lifestyle.
He walks to campus, works out with his brother, and maintains a good diet.
Reflects the societal focus on appearance over health and individuality.

Maintain a self-reflective approach to body image: Are you happy with your weight, and what must change—diet, activity, attitude?
Understand personal genetics versus environmental control over body shape and size.
Discusses societal and cultural influences on body image over different historical periods.
Recognizes that ideals fluctuate across time and cultures, defining health over attractiveness.

Criteria for defining a healthful body weight:
- Appropriate for age and development.
- Achievable and sustainable without extreme dieting.
- Compatible with optimal health markers (normal blood pressure, lipids, glucose).
- Relative to one's genetic and familial context.
- Based on healthy eating and regular exercise habits.
- Personally acceptable and reasonable.

Standards of beauty and health are influenced by cultural norms that differ widely.
Acknowledges that a healthful weight does not conform to extreme body types seen in media.

BMI as a measure, using formulas:
- Metric: BMI (kg/m²) = weight (kg)/height (m)²
- Imperial: BMI (kg/m²) = [weight (lb)/height (inches)²] * 703
Categorizes individuals into five weight classes according to their BMI:
- Underweight: BMI < 18.5 kg/m².
- Normal weight: 18.5 ≤ BMI < 24.9 kg/m².
- Overweight: 25 ≤ BMI < 29.9 kg/m².
- Obesity Class I: 30 ≤ BMI < 34.9 kg/m².
- Obesity Class II: 35 ≤ BMI < 39.9 kg/m².
- Severe obesity: BMI ≥ 40 kg/m².

BMI does not differentiate between fat and lean mass, or the location of fat storage, which can influence health risks.
Specific populations (e.g., older adults, athletes) may misrepresent their health through this measure.

Importance of assessing body fat percentage and fat distribution (waist circumference).
Apple-shaped distribution increases health risks compared to pear shape.
Techniques for measuring body composition include:
- Underwater weighing.
- Skinfold measurements.
- Bioelectrical impedance analysis (BIA).
- Dual-energy X-ray absorptiometry (DXA).
- Bod Pod measurement.

Fundamental equation: Energy balance occurs when energy intake equals energy expenditure.
Energy deficit leads to weight loss; surplus leads to weight gain.

Basal Metabolic Rate (BMR): Energy used for basic physiological functions (60-75% of daily energy use).
Thermic Effect of Food (TEF): Energy expended during the digestion and storage of food (5-10%).
Physical activity: Varies individually from minimal (NEAT) to vigorous activity (15-35%).

Significant heritability linked to obesity. Factors can account for 50-70% of BMI:
- FTO gene linked to increased hunger and weight gain.

Diet patterns and opportunities for physical activity are often mitigated by societal structures, including fast food availability, work habits, and socioeconomic status.

Approaches include: Lifestyle modification, medications, and surgeries for severe obesity.

Emphasizes a balanced lifestyle, focusing on gradual, reasonable changes and understanding personal health goals.
Advocates for mindful practices around eating and activity rather than extreme measures.