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59 Cards in this Set

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How does being overwt develop (4)?
1. During growth, number of fat cells increase

2. When energy intake > expenditure, fat cells increase in size

3. When fat cells reach max size, if [intake > expenditure] continues, the number of cells can increase.

4. With loss of fat, the size of the cell decreases, but not the number.
What is LPL?
lipoprotein lipase
Where is LPL present?
In the membranes of fat cells. So more cells = more LPLs. More LPL activity leads to more efficient fat storage.
LPL is localized in fat cells. What does this mean for women?
Breasts, Hips, and Thighs.
LPL is localized in fat cells. What does this mean for men?
Abdoment (central obesity)
Fat breakdown enzymes is less active where?
It is less active in the lower body than in the upper body. This means it is difficult to lose weight in the hips and thighs.
What is Set-Point theory?
Biochemical/Physiological processes tend to counterbalance changes.
For example:

1. Wt loss leads to an increased synthesis of LPL which leads to more fat storage.

2. Wt loss leads to decreased energy expenditure and this leads to wt gain

3. Wt gain leads to increased energy expenditure and this leads to wt loss.
What are the "causes" of obesity?
Genetic factors and personal choices.
How are genetic factors related to obesity?
They may determine or influence susceptibility but do not cause obesity.
What does the ob gene code for?
Leptin. This suppresses appetite and increases energy expenditure.
If there is an increase in body fat what happens to leptin?
Leptin is synthesized and its conc. in the blood increases. This results in a suppression of appetite and increases energy expenditure.
If there is a loss of body fat what happens to leptin?
The concentration of leptin in the blood decreases. This results in increased appetite and decreases energy expenditure.
A defective ob gene leads to what?
Uncontrolled wt gain.
Some, but not most, obese people have a ? ? ?.
Some, but not most, obese people have a defective ob gene.
One problem with obese people may be that their fat cells are ? to the action of leptin.
One problem with obese people may be that their fat cells are resistant to the action of leptin (analogous to Type 2 diabetes)
Remember: What is problem in Type II diabetes?
Type II has enough insulin but just can't use it.
What are leptin effects mediated by?
Neuropeptide Y (NPY)
What is NPY?
A peptide hormone that stimulates the appetite and reduces energy expenditure.
What does increased leptin cause?
1. Increased leptin decreases appetite and increases energy expended

2. It causes a decrease in NPY
What does NPY do to energy expenditure and appetite?
increased NPY = increased appetite = decreased en. exp
What does leptin do to energy expenditure and appetite?
Increased leptin = decreased app = increased en exp

(because it decreases NPY)
What does Ghrelin do?
It stimulates appetite and promotes efficient energy storage.
What causes changes in ghrelin level?
PYY, a peptide secreted by GI cells in response to food intake, lowers ghrelin levels.
What effects do PPY have?
Opposite effects of Ghrelin by acting on Ghrelin. (so it decreases appetite and decreases energy storage)
There is a clear correlation between being overwt and what diseases?
1. Cardiovascular disease

2. HTN

3. Diabetes
What does everyone experience in losing wt?
Everyone experiences short-term wt fluctuations. (eg. water weight)
What percent of all people who lose wt maintain that loss for at least a year?
Only 5%
What does "weight-cycling" ("yo-yo") decrease, what does it increase?
It decreases the probability of long-term wt loss, and appears to increase the risk of chronic disease (eg, type 2 diabetes)
What is better then "weight-cycling"?
Stability, even if overweight, is better than cycling.
What are the options for losing weight?
If a person has clear health problems (like HTN) and a high BMI, depending on the seriousness, the options are:

1. Surgery

2. Medications

3. Diet modification
What does one need to be cautious about in the drug treatment of obesity?
1. Short-term use : in conjunction with diet-control and exercise, can lose ~10% of wt but regain is common

2. Long-term: risks and benefits not fully understood
List 2 Rx medications approved by the FDA for long-term use?
1. Sibutramine (Meridia)

2. Orlistat (Xenical)
How does Sibutramine (Meridia) work?
Suppresses appetite by inhibiting serotonin reuptake (a SSRI)
How does inhibiting serotonin reuptake suppress appetite?
It is a neurotransmitter, which suppresses appetite and induces fatigue. Low levels are associated with depression. Any agent that prevents its reuptake increases its concentration.
Sibutramine (Meridia) should not be used by whom?
Anyone with high BP
How does Orlistat (Xenical) work?
It inhibits pancreatic lipase, blocking fat digestion and absorption.

(this is now available OTC)
What is an FDA medication for losing weight approved for OTC use? How does it work?
Benzocaine (Diet Ayds, Slim Mint): It anesthetizes the tongue, reducing taste sensation.
What is a drug that the FDA has not approved?
Phenylpropanolamine (mkted under various names like Dexatrim).

Multiple possible side effects: dry mouth, rapid pulse, nervousness, sleeplessness, htn, irreg heartbeat, kidney failure, seizures, strokes.
What is brown fat?
When uncoupling allows the body to use energy without producing ATP. A little uncoupling may be OK but a lot is not.

For example DNP is an uncoupler that at too high a concentration is dangerous. It burns energy without ATP so there is no storage and so there is decreased wt but disastrous side effects.
What is St. John's wort?
An herbal OTC that appears to suppress appetite.
What is ephedra/ephedrine?
Herbal product that can be alone or with caffeine. Extracted from ma huang ("natural"). Showed promise for obesity tx. It is now implicated in serious problems. The sale is banned by the FDA.
In dieting the primary focus must be on what?
Health improvement, not just wt loss.
How much wt loss can be beneficial?
Even a modest wt loss (like 5 lbs) can be beneficial if sustained.
What is a reasonable goal recommended for a reasonable and sustainable wt loss?
5-10% of total body wt.
How long should you give yourself to lose 10% of your body wt?
6 months
To lose 10% of 200lbs what should you aim to lose weekly?
1 lb/week
What does 1 lb of fat equal in kcal?
3500 kcal
What is a reasonable amount of weight to lose a week?
1/2 - 2 lb/week

(1750-7000kcal week)
(250-1000 kcal/day)
List 7 components of an eating plan to reduce wt.
1. Reduce energy intake (eg, by 500kcal/day)

2. Maintain nutritional adequacy

3. Small portions

4. Include complex carbs

5. Minimize fats

6. Minimize "empty calories"

7. Drink plenty of water
How might you maintain nutritional adequacy?
Make sure you have high nutrient density and never eat less than 1200kcal/day. So you need to keep in 'good' foods (vit., min., and proteins) and cut empty calories.
It is important to include complex carbs in any eating plan, esp what kind?
Fiber
What kind of fats should esp. be minimized in a diet plan?
Saturated fats.
What are some 'empty calories' that can be minimized in a diet plan?
Fats, sugars, and alcohol
What kind of fat is primarily decreased by exercise? What cannot be done?
Abdominal fat. You cannot target wt loss to other areas by targeting exercise.
What is the most effective way for physical activity to help control appetite?
Sustained activity of moderate intensity.
List 4 psychological factors that may aid wt control.
1. Set reasonable (attainable) goals

2. Find reasonably enjoyable ways of reaching these goals

3. Support groups (wt watchers) may help

4. If habits are unchanged, there is a much greater probability of maintaining the wt loss, which should be the goal.
What is not as prevalent as overweight in developed countries?
Underweight
What is the solution to being underwt?
Must combine diet and exercise.
List 6 components of a diet for underwt individuals?
1. Emphasize high energy foods (even fats, esp. mono and polyunsat fat)

2. Regular meals

3. Large portions

4. Extra snacks

5. Juice and milk

6. If exercising more, need to increase caloric intake.