Energy balance/body composition

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.

FOOD INTAKE

* 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

External Controls

*      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

Conservative

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

Fat Distribution-

*      apple – intra-abdominal fat stored around organs of abdomen

*      central obesity more common in men, increases risk of cardiovascular disease, diabetes, mortality

*    &n