Unit 6 Flashcards
Energy Balance
energy in =energy out
- a shift in balance causes weight change
- rapid changes are gradual
excess energy stored as fat
- fat is used as fuel between meals
- 20% of lost weight is lean mass
- to lose 1 pound, need to expend extra 3500 kcals than your body needs
- all gets broken down to acetyl CoA and turned to fat
Appetite
- psychological
- cues, after dinner you smell dessert and are no longer full.
- environmental impact on our appetite
Energy In: food consumption
bomb calorimetry
- as foods burn - heat, CO2 and water
-calc the cals from energy-yielding nutrients
- amount of heat/how it burns = how many cals
1kcal of energy needed to heat up 1 kg of water by 1 degree
Hunger
- physiological response - body telling us we need nutrients, nerve impulses and chemical messengers interacting w brain via hypothalamus.
Satiation
stop eating, feeling of fullness
- exercise - makes you not wanna eat
Satiety
- do not start eating again
- overriding factors - stress, boredom, socialization, easy access
Energy out: components of energy expenditure
thermogenesis: production of energy - releasing heat
- basal metabolism - amount of energy body needs every day to maintain base
RMR- resting metabolic rate
BMR- basal metabolic rate. Very base rate of food you need. Measured first thing in the morning
Food consumption
thermic effect of food -> warm feeling after eating. Body needs energy to digest and absorb nutrients. Normal meal doesn’t raise too much. More w a big meal
adaptation responses
metabolism during an infection.
metabolism is higher, body is trying to keep homeostatic state
Factors influencing energy out
- height - higher metabolic rate
- growth - growing ppl have higher metabolic rate
- body comp- more energy needed to maintain fat than muscle. therefore men have higher metabolic rate
- hormones
- stresses
- environmental temp
- smoking increases BMR
- caffiene
factors that decrease the BMR
- age
- fasting/starving: slow down rate to maintain healthy
- malnutrition
- sleep - lower when sleeping
Estimating energy requirements
influenced by:
- sex
- growth
- age
- physical activity
- body comp and size
Physical activity factors
Sedentary: typical daily activities
Low Active: 30-60 mins moderate activity
active: 60 mins or moderate activity or more
very active: 60 mins of moderate activity and 60 mins vigorous activity or 120 moderate
BMI calculation
relative weight for height BMI = weight (kg) height (m^2) underweight: <18.5 healthy weight: 18.5-24.9 overweight: 25.0-29.9 obese: 30.0+
Muscle mass
BMI doesnt include muscle mass
Body fat distribution
- important information for disease risk
- ideal amount of body depends on sex
- females have more fat comp than males, need more to survive
Fat distribution
visceral fat: the real problem for metabolic diseases
- central obesity
subcutaneious fat
Waist circumference
Indicator of visceral fat - fat surrounding organs
- women: >25in
- men >40 in
Health risks associated with body weight and body fat
- body weight and fat distribution and fat distributed correlate with disease and life expectancy
risks associated with being underweight
fighting against wasting diseases (cancer)
menstrual irregularities and infertility
osteoporosis and bone fractures