Eating Behaviour Flashcards
What is the set point theory?
Kennedy (1953)
Is the lipostatic model of body fat regulation
Suggests that body fat operated on a negative feedback loop around a target set point
Any deviance from this point would force the body to increase or decrease intake of food
What is NEAT?
Levine et al (1999)
Non exercise activity thermogenesis
Non obese adults were given an excess of 1000 calories per day. To counter this their neat increased
What is dual intervention points?
Levitsky (2002)
Suggests we have two intervention points cultivated by evolution
The lower point was evolutionary pressure to avoid starvation
The upper point was the evolutionary pressure to avoid predation
The upper point has been allowed to slowly drift through time due to a lack of predation, which has caused the obesity crisis today.
What are the two food stores?
Short term store in the liver and muscles
- converts glucose to glycogen
- stimulated to do so by insulin
Long term store in adipose tissue
What have the size of fats cells to do with obesity
Fat cells store Triglycerides.
Cells can expand enormously with obese people’s cells being larger
What are the two phases in our metabolism?
Fasting phase - where nutrients are not available from digestive system and are instead glycogen in liver and adipose tissue
Absorption phase - nutrients are available from digestive system. Liver converts glucose to glycogen. Excess nutrients stored as fat in adipose tissue
What is the general model of intake regulation?
De Castro and Plunkett (2002)
Suggests intake controlled by two factors
- Uncompensated factors (primarily environment)
- Compensated factors (primarily physiology)
Compensated has negative feedback loops, uncompensated affects intake but is not affected by it.
What is the thrifty gene model?
Neel (1962)
Suggested gene developed during historical people were able to process food more efficiently
What was found by segal et al?
Segal et al (2009)
Ran a study with 929 individuals from monozygotic and dizygotic twins.
Found genetic components play an essential role in BMI covering 63.6% of the variance. Also environmental factors of diet and exercise affect BMI covering 25.7% of the variance.
Do social factors play a role in eating behaviour?
Herman and polivy (2005)
- People who are in an unfamiliar environment where they have no pre existing norms may look to others for guidance
- when norms are not salient people will eat as much as they like
- there is a general social facilitation effect where people eat more in groups
- people tend to eat less in the presence of family members to make a good impression
What study on environmental factors was carried out by levitsky?
Levitsky (2004)
Ran a study will university freshmen weighing them at week 1 and week 12 and found a significant weight gain of 1.9 +- 2.4kg
This demonstrates that weight gain can be contributed to environmental stimuli. Could be attributed to the stressful experience of first year.
What is the master area for control of appetite in the brain?
Mendieta-Zeron et al (2008)
Suggests many kinds of information impinge on two cells in the arcuate nucleus of the hypothalamus.
Arcuate nucleus has one set of neurons sensitive to hunger signals and one set sensitive to satiety.
What studies help advocate environmental factors of eating?
Segal et al (1999) genetic study.
Levitsky (2004) college students study
Herman and polivy (2005) social norms
How does adipose tissue signals influence food intake?
Woods (2005)
Insulin from the pancreatic B cells and leptin from white
adipose tissue (and other tissues) are each secreted in direct proportion to the amount of fat stored in the body
if exogenous insulin or leptin is added locally into the brain, the individual responds as if excess fat exists in the body; i.e., food intake is reduced and body weight is lost.
Analogously, if either the leptin signal or the insulin signal is reduced locally in the brain, the individual responds as if
insufficient fat is present in the body, and more food is eaten and the individual gains weight.
What is the difference between satiety signals and adiposity signals?
Satiety signals regulate how many calories are eaten during each meal.
However Adipose signals are related to how much fat the body carries and maintains
