Body Weight and Body Composition: Defining healthy body weight
Body Mass Index
healthy weight
BMI 18.5 to 24.9
Underweight
BMI <18.5
Overweight
BMI 25.0 to 29.9
Obese =
BMI > 30
Body composition
Central obesity
“Apple profile” of central obesity
- common in postmenopausal women and even more common in men
- Influential factors: smoking, alcohol consumption, and physical activity
“Pear profile” created by subcutaneous fat
Waist circumference
Skinfold measures
How much body fat is too much?
Health Risks of Obesity
Causes of Obesity
Genetics and Weight: Lipoprotein Lipase (LPL)
“lets store more fat!”
- cell surface enzyme that hydrolyzes triglycerides and promotes fat storage
- higher level of LPL activity in fat cells of obese people - makes fat storage efficient
Genetics and Weight: Leptin
Genetics and Weight: Ghrelin
Fat Cell Development (4 steps)
Obesity Treatment: Principles
Reasonable Strategies for weight loss to lower disease risk
Maintain a lower body weight over the long term
At minimum, prevent further weight gain
A healthful eating plan
A realistic energy intake
- provides less energy than the person needs to maintain present body weight
- Not too restrictive
- men: 1500-1800 kcalories per day
- Women 1200-1500 kcalories per day
Nutritional Adequacy
Reasonable Strategies for Weight Loss: A Healthful Eating Plan
Reasonable Strategies for Weight Loss: Physical Activity
Physical activity: more likely to lose more fat, retain more muscle, and regain less weight when physical activity is combined with energy restriction. Reduces abdominal obesity; improves blood pressure, insulin resistance, fitness of heart and lungs
Energy expenditure: directly increases energy output. energy spent on various activities differs.
Basal Metabolic Rate (BMR): elevated following vigorous physical activity. Rises over time as more lean tissue is added