QUESTIONS

1. What % above normal body weight do you have to be to be called obese?
   
   a) 10-15%         b) 20-25%         c) 30-35%         d) 40-50%
    
2. Which is the primary cause of obesity in our pets: under-exercise or over-feeding?
    
3. What is the difference between hyperplastic-hypertrophic obesity & hypertrophic obesity?
    
4. Why is spaying believed to predispose to obesity?
    
5. Describe the proposed hormonal basis for the tendency for obesity that occurs with age.
    
6. In an obesity management program, how should you calculate how many Calories to feed?
    
7. One way to get a dog to reduce weight is to simply starve it until it weighs whatever you want. How is this possible without danger?
    
8. What 3 important substances come from the oxidation of arachidonic acid?
    
9. There are 2 systems of nomenclature for poly-unsaturated fatty acids (PUFAs). One uses numbers and the other refers to "omega" structure. Describe how to name a PUFA with each system.
    
10. What is the only source of arachidonic acid? (hint: cats cannot make arachidonic acid from linoleic acid as most other species can.)
    
    
    
    
     

ANSWERS

1. b) 20-25% above optimal weight makes one obese.
   
   
   
   
    
2. Over-feeding is the primary cause of obesity in our pets.
   
   
   
   
    
3. Hypertrophic obesity occurs when an adult eats/makes too much fat & the adipocytes fill way up with lipid. In hyperplastic-hypertrophic obesity and immature person or animal is eating/making too much fat. In this case, the adipocytes still have the ability to divide & they do. The end result is more adipocytes filled way up with lipid.
   
   
   
   
    
4. Well, this is what all the literature says.  Estrogen has an appetite suppressing effect & when you lose estrogen you lose this effect.  What I wonder is how important this could be for dogs when they are anestrus for months & months.  Does any one have thoughts on this?
   
   
   
   
    
5. DHEA = dehydroepiandrosterone
   
   This hormone & its metabolyte DHEA-sulfate are the major secretory products of the adrenal gland. They are also the most abundent steroid other than cholesterol. Hormone levels of DHEA in humans peak between ages 20-30 & then decline 20% for every decade after age 25 (you're hanging at about 5% when you're 85-90 years old).
   
   When you give DHEA to obese rats or dogs, they lose weight without changing their food intake.  (Their choesterol level drops, too).  The idea is the hormone keeps you thin & you lose it as you age.
   
   When I read this I nearly passed out.  When can I get some? When can this be used clinically?  Dave, what's the haps on this ?
   
   
   
   
    
6. The idea is to give plenty less Calories without too much begging for food.  A typical recommendation is 60%of the Caloric requirement needed for the optimal weight (for dogs & 66% for cats). Breaking this into frequent feeding also helps.
   
   
   
   
    
7. In starvation ketone bodies are produced & for most species this is a problem but not for dogs. Dogs are very efficient at burning ketones peripherally so they don't have the metabolic dangers that other species have in starvation. The downsides of starvation include first that it is appalling to clients and also it does not teach a new "dietstyle" to the client so obesity may simply recur when unhealthy feeding patterns are resumed.
   
   
   
   
    
8. Arachidonic acid is oxidizes into prostaglandins, thromboxanes, & leukotrienes.
   
   The enzyme CYCLOOXYGENASE is responsible for prostaglandins & thromboxanes while LIPOXYGENASE is responsible for leukotrienes.
   
   
   
   
    
9. Lets use arachidonic acid as an example. Arachidonic acid has 20 carbons, & 4 double bonds. Like all fatty acids, it has a carboxyl group on one end & a plain methyl group on the other end.
   
   Using the number system, arachidonic acid is:
   
   5,8,11,14
        C:4
          20
   
   This means that counting from the methyl group, there is a double bond at the 5th, 8th, 11th, and 14th position.
   
   The problem with this method is that as carbon chains change in length, it becomes impossible to tell anything about the chemical behavior of the fatty acid in question. It is much more useful to count from the carboxyl group.
   
   Using this method, arachidonic acid has a double bone at the 6th position from the carboxyl group.  This makes arachidonic acid an "omega 6" or N-6 PUFA. Linoleic is also an omega 6 PUFA.  Linolenic acid has a double bond at the third position from the carboxyl group & is thus an N-3/omega 3 PUFA.
   
   
   
   
    
10. Animal tissue is the only source of arachidonic acid.