ENERGY BALANCE & BODY COMPOSITION
* The body’s remarkable machinery can cope with many extremes, however, a grossly unbalanced diet imposes hardships on the body.
* If energy intake is too low-the body must degrade its own lean tissue to meet its glucose and protein needs.
* If energy intake is too high-the body stores fat.
* To achieve energy balance the body must meet its needs without taking in too little or too much.
Hunger – (need) a physical need for food-motivates eating hypothalamus- brain center that controls activities such as hinger and thirst
Appetite – (desire) craving – exposure to…sight, smell, thoughts, sounds, etc.
Satiation – the feeling of satisfaction and fullness-determine how much food is consumed
Satiety – feeling suppresses hunger-reminds us not to start eating- a sense of satisfaction- determines the period of time between meals
Overriding hunger/satiety – sometimes eating is caused by other signals than hunger
Exposure to palatable foods – dessert
Need sensory satiety- sweet salty- etc.
Temporal cues –usual mealtimes, locations, sounds, smell, etc.
Social customs – clean your plate-don’t waste food-polite don’t refuse
Emotional/psychological – stress, anger, depression, boredom, sadness funerals… happy occasions, celebrations, holidays, religious observance
Desire to change body size
ENERGY OUT PUT
BMR – Basal metabolic rate the energy needed to maintain life when at rest
Physical activity – voluntary movement (influence on both weight gain/loss
Thermic effect of food – estimation of the energy required to process the food (digest, absorb, store, eliminate
ESTIMATING ENERGY REQUIREMENTS
Gender – in general women have lower BMR than men (lean body mass)
Growth – BMR higher in growing people
Age- BMR declines with age as does lean body mass
Physical activity – various levels of intensity and time
Body composition/size – BMR is higher in people with more body surface
DEFINING A HEALTHY BODY WEIGHT
What should you weigh????
Cultural, economic, health, society, fashion
Past – overweight meant wealth and power
- underweight meant poor and unsuccessful
BODY MASS INDEX- BMI – PAGE 263
-has limitations height and weight only
Healthy weight- 18.5 – 25
Underweight – below 18.5
Overweight – over 25
Clinically severe obesity over 35-40
According to BMI statistics over ½ of all adults in US have a BMI over 25
APPLE/PEAR BODY SHAPES
apple – intra-abdominal fat stored around organs of abdomen
central obesity more common in men, increases risk of cardiovascular disease, diabetes, mortality