Lecture 10 - Weight Management: Overweight & Obesity Flashcards
Where is fat stored?
Fat cells are stored in adipose tissue
What does body fat reflect?
Depending on what it looks like can reflect the number and size of fat cells
When do fat cells grow the most?
In growing years they grow the most rapidly
What is adipose tissue similar to?
An endocrine system
What determines how our fat cells grow?
It is genetically predisposed
What happens when fat cells die off?
They don’t really die off, they shrink
Which demographic has a higher level of fat cells?
Obese individuals have more fat cells
How are fat cells developed?
When energy in > energy out
What happens when enlargement of fat cells becomes too much for adipose tissues?
Fat may accumulate in other areas of the body
-visceral
What happens to fat cells when energy out > energy in?
- Fat cell size decreases, there is no change in the NUMBER of fat cells
- ectopic fat decreases
- Adipokine profile begins to improve with as little as 5% weight loss
What is LPL’s role in fat cell metabolism?
LPL takes up triglycerides into tissues
-LPL activity is increased in obese people
What does LPL levels depend on ?
Genetics and where you store your fat
What happens to LPL activity when you lose weight?
LPL activity increases
- is it released when fat cells shrink because the body thinks its not getting enough energy, so they shrink in hopes to regain the weight
- very efficient at regaining the weight
What is the set point theory?
The body likes to maintain homeostasis
-body tries to adjust to original weight either by increasing metabolism or decrease LPL activity
What are the main causes of overweight and obesity?
Genetics: determine preposition to obesity
- genetics interact with diet and physical activity
- physical activity can minimize the genetic influence on body weight
Epigenetics
What is Leptin?
Act as a hormones in the hypothalamus to maintain homeostasis and promotes a negative energy balance
- supresses appetite
- increases energy expenditure
What is leptins nickname?
The obese genes
- produced in adipose tissue
- codes for the leptin protein
What is leptin resistance?
- Production levels increase/decrease with BMI
- Does not suppress appetite or enhance energy expenditure
What increases leptin resistance?
Excessive fracture consumption induces leptin resistance and accelerates fat storage
What is Ghrelin?
Protein made in the stomach to stimulate appetite by actin on the hypothalamus
How do levels of Ghrelin vary?
Levels increase after weight loss
- lack of sleep increases and decreases levels
- we are sensitive to effects regardless of weight
What happens if you lose the ability to produce leptin?
Ghrelin will still be produced and at an even higher level
What is the cause of obesity and overweight ?
Physical inactivity Childhood weight Behavioural factors -food choices -hunger vs appetite Social factors -expectation of body types
What is the DRI for physical activity?
60 mins of moderate activity to prevent weight gain
150 min of moderate-vigorous activity per week for health benefits
Why doesn’t exercise lead to weight loss?
Because NEAT accounts for those excessed calories, so exercise is just for health benefits