Energy Balance

Energy Balance

I Energy Balance
A. Body weight is stable when energy consumed is equal to energy expended.
B. When energy consumed is greater than expended, weight increases.
C. When energy consumed is less than expended, weight decreases.
D. The value of 1 pound of body weight (fat) = 3500 kcalories
1. must expend 3500 kcal over and above normal activity to burn 1 pound of fat.
II Energy In: The kCalories Foods provide
A. Eating behaviors respond to different signals.
B. Hunger and appetite encourage eating while satiation and satiety stop eating.
C. Messages are sent from the hormonal and nervous system. (can take time for the brain to get the signal to stop eating)
D. Other aspects of human behavior affect eating habits
E. Food intake:
1. appetite intitiates eating through:
a. sight
b. smell
c. thought
d. taste of food
2. hunger: the feeling that motivates us to eat and is controlled by the hypothalamus.
a. If you don’t eat for a few days, you lose hunger. It can be hard to get someone to begin eating again because they aren’t hungry.
3. satiation: the feeling of satisfaction and fullness that causes us to stop eating.
4. satiety: reminds us not to eat again until the body needs food.
III Energy Out: The kCalories the Body Expends
A. Energy expenditure includes:
1. basal metabolic activities (involuntary)
2. physical activity
3. thermic effect of food and adaptive thermogenesis (amount of energy required to digest food)
B. These energy requirements differ from person to person and are affected by:
1. age
2. gender
3. weight
4. height
5. intensity and duration of physical activity
C. Components of Energy Expenditure
1. basal metabolism (BMR, basal metabolic rate)