ESS 3 Lecture Notes - Lecture 7: Cytosol, Hyponatremia, Triglyceride
BMI
➔Way to categorize people into if they are healthy or unhealthy according to their weight
➔Measure of body weight relative to height
◆<18.5 = underweight
◆18.5-24.9 = healthy
◆25-29.9 = overweight
◆30 = obese
➔Does not take body composition into account
◆Does not measure muscle
● Average height/shorter + muscular = labeled as obese
➔BMI = weight (kg) / height (m)^2
Energy balance
➔Energy balance: occurs when energy intake = energy expenditure
➔Energy intake: kcal from food
➔Energy expenditure: energy expended at rest, during physical activity, and a result of
eating food
Obesity results from a chronic imbalance in energy intake and expenditure
➔energy intake > expenditure = weight gain
➔Hormonal changes associated with obesity result in a low-grade chronic inflammation
◆Enlarged fat cells produce excess hormones
● Hormones cause low-grade inflammation (direct correlation to disease)
◆Adverse health effects and increased risk of chronic disease
Energy balance is hormonally regulated
➔Two ways
◆Short-term system: mediated by ghrelin
● Mediated by stomach pressure
● Regulates hunger and satiety
● Ghrelin: produced in the stomach
○Stimulates hunger
◆Long-term system: mediated by leptin
● Adjusts food intake and energy expenditure
● Maintains adequate fat stores
● Leptin: produced by adipose tissue
○Suppresses hunger (acts like insulin)
Total energy expenditure (TEE)
Basal metabolism 60%
➔⅔ of daily energy
➔Amount of calories necessary to keep organs functioning at rest
➔Metabolic activities:
◆Basal metabolic rate (BMR) / Resting metabolic rate (RMR)
find more resources at oneclass.com
find more resources at oneclass.com
◆Primarily determined by:
● Weight
● Lean tissue
➔A lean individual expends more energy at rest than someone with more body fat
◆Skeletal muscle is 3x more metabolically active than adipose tissue
Thermic effect of food (TEF) 10%
➔Energy needed to digest, absorb, and metabolize nutrients in food
➔10% of the energy content of food ingested
➔Does not vary greatly between people
Activity energy expenditure (AEE) 30%
➔Physical activity
◆Voluntary movement of skeletal muscles
◆Most variable component of energy expenditure
◆Amount of energy needed based on:
● Muscle mass, body weight, activity
Thermogenesis: generation of heat
➔Measure of energy expended involuntarily
➔Occurs when we are digesting food
➔Adaptive thermogenesis: adapting to dramatically changing circumstances
◆Ex: extra work done by body
◆Amount expended is extremely variable
➔NEAT: non-exercise activity thermogenesis
◆Impact on the risk of obesity
● Obese individuals spend more time sitting and less time moving
Body fat and distribution
Waist circumference is an estimator of abdominal obesity
➔Measuring assesses presence of abdominal obesity
➔Viscera (abdominal) fat is an independent health risk
◆Cardiovascular disease
◆Type 2 diabetes
◆Insulin resistance
◆Premature all-cause mortality
How low is unhealthy?
➔3-5% for men
➔10-12% for women
➔Body fat is essential in manufacturing of hormones
➔Provides cushion for internal organs
➔Low body fat levels
◆Delayed physical maturation during adolescence
find more resources at oneclass.com
find more resources at oneclass.com
◆Infertility
◆Amenorrhea (cessation of menstruation)
◆Accelerated bone loss
● Decrease in bone density
Goals of obesity treatment
➔Achieve and maintain clinically meaningful weight loss
➔Losing and maintaining 5-10% of initial body weight represents clinical success
◆Reduces risk of chronic disease
➔Long-term success dependent on maintenance of 10% weight loss at one year
➔<20% overweight and obese adults are successful at one year and longer-term success
is lower
➔Treatment options
◆Effective approaches:
● behavioral/lifestyle intervention, dietary modifications, increased physical
activity
◆Weight loss surgery
◆Anti-obesity medications
● Appetite suppressant, metabolic effects, nutrient absorption
Physical activity
Physical activity: any bodily movement produced by skeletal muscle that causes energy
expenditure
Exercise: intentional physical exertion
➔Short-term benefit
◆Helps people lose body fat
◆Builds muscle mass
◆Helps people become physically fit
➔Long-term benefits
◆Maintains healthy body weight
◆Reduces the risk of heart disease, stroke, type 2 diabetes, cancer
◆Manages stress
◆Reduces anxiety and depression
➔Promotes physical fitness
◆Physical fitness: ability to perform moderate to vigorous activity without undue
fatigue
ACSM recommend four types of physical exercise to promote health
➔Resistance training (strength training)
◆Increases muscle strength, improves body composition, and promotes bone
health
➔Cardio
◆Increases the heart rate and promotes use of oxygen
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Way to categorize people into if they are healthy or unhealthy according to their weight. Measure of body weight relative to height. Does not take body composition into account. Average height/shorter + muscular = labeled as obese. Bmi = weight (kg) / height (m)^2. Energy balance: occurs when energy intake = energy expenditure. Energy expenditure: energy expended at rest, during physical activity, and a result of eating food. Obesity results from a chronic imbalance in energy intake and expenditure. Energy intake > expenditure = weight gain. Hormonal changes associated with obesity result in a low-grade chronic inflammation. Hormones cause low-grade inflammation (direct correlation to disease) Adverse health effects and increased risk of chronic disease. Amount of calories necessary to keep organs functioning at rest. Basal metabolic rate (bmr) / resting metabolic rate (rmr) A lean individual expends more energy at rest than someone with more body fat. Skeletal muscle is 3x more metabolically active than adipose tissue.
