Chapter 9 Weight Control

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Refer also to chapter on energy balance

                
Causes of obesity
 Body fat accumulates when people consistently consume more energy than they spend.

Fat cell development
The amount of fat on persons body reflects both the number and the size of the 
fat cell. The number of fat cells increases most rapidly during the growing 
years of late childhood and during puberty

   Fat cells can expand in size. . When they reach their maximum they 
may divide. . Obesity then develops when fat cells increase in number
in  size or quite often in both. 
    With fat loss the fat cells shring in size but not in
number = people with history of obesity tent to gain weight more 
readily then people without history of obesity.Prevention of obesity 
is thus most critical especially in years when there is ncrased 
chance for fat cells to multiply in numbers.    

We recognize 2 types of adipose tissue
a) white - primarily stores fat- oxidation produces heat and ATP 
b) brown produces heat - oxidation produce only heat
 Children have lots of brown adipose tissue to keep them warm
 Adults have only small amounts of brown adipose tissue.

       Genetic
When both parents are obese the chance that their child will be
   obese is about                                           80%
When one parent is obese                                    40%
when no parent  is obese                        Less than   10%


       Obese gene-leptin
								
     In recent years scientist have discovered a gene that they labeled
an obese gene. . This gene has been found to have influence over signaling
our body to stop eating. It functions in fat cells.As every other gene, it produces
a hormone or protein that we call LEPTIN. Leptin then signals brain  to stop
eating. The mechanism upon which  the functioning of this hormone exactly
works remain to be subject to further studies, but preliminary studies suggest that 
once fat cells are saturated with fat from meal they will secrete leptin to halt 
urther intake of food.
 If fat cells are running low on fat they will reduce secretion of leptin thus 
signaling body to increase intake of food. This seems to be promising tool in
controlling weight in obese individual. Problem seems to be however, that same 
individual despite increased production of leptin wont get the feeling of
brain induced satiety, because of cell’s resistance to hormone leptin much like
in insulin resistance in case of diabetes.

            Fat cell metabolism
   Some researches focuses on another genetic influence for obesity. They focus
on enzyme Lipoprotein Lipase which promotes fat storage in fat as well as muscle
tissue. People with high activity of LPL are especially prone to fat storage.
     The activity of this hormone is particularly regulated by sex hormone-estrogen
and testosterone thus we can explain why women has increased fat deposits in breast,
hips and thighs and man around waist. It is these areas that LPL is most active
     LPL is also one of the culprits for failure in maintaining lost weight .
It has been found that LPL's activity increases after weight loss. It seems as if
body responded to weight loss by producing larger amount of LPL to maintain its fat
stores. This partially explain the set point theory that claims that inner mechanism
try to maintain persons weight at a set point and that if anything is done to change
it the body will adjust it back to the set point.

         Set point theory

    As pointed above body tries to keep its weight at certain set point and so it
can bee seen that body adjust its metabolism whenever it loses or gains weight, 
so that weight returns to its original place. If there is weight gain energy 
expenditure will increase and with weight loss energy expenditure decreases. 
This explain why is it so hard for obese person to keep his wt loss. 

   Inactivity
    Some people are obese not because they eat too much, but because they are
extremely inactive.Dietary recall may reveal that they may eat far less than the 
lean person, but because they are extremely inactive they still have energy surplus.
If we attempted to reduce their energy intake even further we would run the risk of 
creating nutrient deficiencies and jeopardize their health.
   Rule of thumb is then, that if you want to provide your body with sufficient
nutrient without unhealthy weight gain, you need to exercise.

   As we have seen, there is no one cause for obesity rather multiple factors 
interplay in creating this rather difficult condition to deal with.

    Controversies in obesity treatment

    One thing to remember when attempting for treatment of obesity is that only 5%
of all people who try to loose wt will be able to maintain this wt loss, and that 
most people no matter what, cannot become slender. But inspite of all this encouraging
wt loss is justifiable when it is for purpose of preventing health risks. Obesity
is associates with whole array of chronic disease ranging form diabetes to
cardiovascular diseases, and sensible wt loss can halt their  occurrence.


             Treatment of obesity -poor choices

Weight cycling
     This is a term known also as Yo-Yo dieting. It is familiar to all those who 
attempted for wt
loss and gained their wt back shortly after going off their diet.  Unfortunately with 
repeated wt loss, and wt gain our bodies become very efficient in making and storing
fat and so dieters may notice that after every attempt for wt loss their rebound 
moves a bit higher on the wt scale. This is quite dangerous scenario that makes
future wt loss attempts harder and also lead to slow but steady increase in wt gain.

Surgery for wt loss
 Gastric partitioning is a procedure that is used to treat clinically severe obese
individuals. The food intake is limited by reducing the size of stomach . They also reduce 
the size of the outlet from stomach to small intestine thus increasing delay of food 
passing into small intestine. It is however associated with range of complications and 
lifelong medical supervision is necessary.

    Very low Kcal diets

    They are used for very obese people who may become frustrated with standard graduate
weight loss and loose motivation. VLCD provide thus quick jump start and rapid wt loss .
During their program clients are on prescribed liquid formulas and don’t have to worry 
about making any selection on foods to eat. This may provide person with a sort of 
break from bad eating habits and help them establish a new eating pattern once diet
is finished.
     Plan provides about 800 kcal , little or no fat and little CHO  -not enough 
to spare protein.Client also receives multiple vitamins and mineral supplements
    This diet regiment is only for short period of time -about 4 months, and needs 
to be under close medical supervision. The wt loss is dramatic, but wt gain is 
unfortunately almost certain.  

     Wt loss is always accompanied with slowing of BMR that will favor wt gain. This 
process of rapid wt loss and steady wt gain is very detrimental to both physical
and mental well being of patient. The biggest part of the program begins at the end 
when patient needs to learn how to maintain the lost wt.

   Thus it can bee seen that wt loss is not an easy task. For that reason only
people whose health will benefit from it or people who have strong motivation 
and use save techniques should attempt for it.
 
       Treatment of obesity
Eating plans
    Major characteristic of wt loss diet is that it should provide less energy than 
person needs to maintain his wt.
    One of the first things to realize is that rapid wt loss always leads to excessive
 wt loss of lean muscle tissue that is metabolically active. People who have 
problems with binge eating should initially start adjusting their eating pattern 
to normal three meal a day pattern with small snacks in between if necessary.


     Nutrition adequacy
     No nutrition plan should provide less than 1200 kcal a day since diets providing 
less than 1200kcal cannot provide all nutrients body needs to stay healthy.  Diet 
plan that creates feeling of starvation   and deprivation tends to lead to irresistible 
urge to binge.. The 1200 Kcal diet plan is what reflects the lowest recommended 
serving sizes in Food guide pyramid.

     Portion sizes
    Person should eat enough to feel satisfied but not necessary full. This can be 
translated to
eating less food at each meal -one piece of chicken instead of two.

     Complex carbohydrate
-try to make  the bulk of your diet coming from complex CHO food like
fresh fruit and vegetable , legumes , whole grains. They contain abundance of vitamin
and minerals and little or no fat.
    Also remember that it takes about 20 minutes for the satiety signal to indicate
fullness, so eating slowly will lead to lesser food intake.
   Clients need to pay attention not just to fat intake but also to intake of sugar
and alcohol which are basis for empty calories.

     Adequate water
     Water fills your stomach between meals thus keeping your satiety-feeling of 
fullness  longer and also dilutes metabolic wastes generated from break down of fat.

     Physical activity
   To loose more weight and lower incidence of regaining weight it is necessary to be physically active not just dieting.. Physical activity also motivates people more to 
stick with their diet plan.

     Activity and the BMR
   Research has shown that number of kcal burned during exercise depends more on body 
weight than on the speed with which the exercise is performed. With continuous exercise 
more lean muscle tissue is developed . This leads to increased metabolic rate and increased 
energy expenditure even at point of resting. This alone enables person to eat more 
without gaining weight and brings pleasure and necessary nutrients.

     Activity and appetite control
     Physical activity helps to curb appetite , especially the one associated with 
boredom and anxiety when person is not really hungry. The physiological rationale
 behind this statement is following. While exercising body release from its stores 
glucose and fatty acids to support the exercise, thus immediately after exercise
person is not hungry because there is ample amount of nutrients in the blood stream.
 At the same time body has suppressed its digestive function because all the blood 
is running into exercising muscles to bring them needed nutrients. Thus
exercise and eating are not compatible. 

     Activity and physiological Benefits
     Physical activity helps to reduce stress by boosting production of endorphin that 
releave anxiety , depression and stress.

     Choosing physical activity
     -Choose activity that you will enjoy and be willing to do on regular basis
- activity of moderate intensity such as aerobic exercise is more effective for weight
  control than short burst of vigorous exercise.
- walking stairs, walking extra block to your house are little examples of extra 
  activities that could become part of your ,daily routine to increase weight loss.



     Behavior and attitude
     To achiever and maintain appropriate body weight behavior modification is 
necessary.. It means that we change our behavior by manipulating factors that trigger 
certain behavior. A behavior occurs as a result of certain stimuli. The more intense is 
the stimuli the more likely is the behavior to occur. This behavior then leads to
certain consequences. Then it depends on how much are the consequences positive or 
negative for the behavior to occur again.

     Applying Behavior-modification strategies
     Don’t try too many changes at the same time. Instead pick one problematic area
that you feel is manageable and try to master it, make it habitual and automatic. 
Once you have achieved mastery over this one trouble area pick another and keep working 
on it till you master it.

     Maintaining weight loss
     Remember that to maintain your weight loss it is necessary to continue following
 the activity and eating behavior that lead to this weight loss..By achieving your 
targeted weight you haven’t cured obesity . You need to continue stay active , it has
to become part of your daily routine.