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Biochemistry
Lec: 5 Dr. Ahmed Dalalbashi
Weight Control:
Weight control is very important during life to prevent health problems
associated with obesity.
It has been observed that Diabetes Mellitus and hypertension occur more
frequently in obese individuals whose blood levels of triglycerides and
cholesterol are usually elevated.
Obesity:
It is defined as the state in which an excess of fat accumulates in the
body. The proportion of fat in the total body weight gives a scientific
measure of obesity.
Mean values of body fat for normal young men are about 12% and for
young women are about 26%.
A man regarded obese when the amount of fat increase more than 20% of
his total weight and a woman is considered obese if her fat increase to
more than 30% than the total body weight.
Obesity may be in both sexes but it is usually more common in women, it
is specially occur after pregnancy and at the menopause.
Now a day's obesity index (Body mass index) is used on a large scale as
an index of obesity or over weight.
Weight (kg)
Obesity Index (BMI) =
Length in (m)
2
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The typical result of this division range is between 20 & 25. When the
result is between 25 & 30 the subject has overweight, While when above
than 30 it is obesity. However, result less than 20 means underweight
especially if less than 18.
Causes:
1. Increased caloric intake, which exceeds the energy needs of the
body.
2. Change in living habits: As the habits in many countries have
developed from that of 50 years ago e.g. work hours have been
shortened, transportation is easier, the homes are well heated.
3. Emotional problems: Many people who are overweight eat because
they have nothing else to do. They may eat more when they are
under stress or when they feel unappreciated.
4. Activity: As obese person is less active than his counterpart of the
same age, this inactivity lower the caloric need of the body and in
this way contribute to overweight.
5. Endocrine: In small percentage of overweight individuals, the
obesity may be due to disturbances of functions of the endocrine
glands such as thyroid and pituitary.
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Prevention:
Usually obesity starts in childhood and continues and increases in adult,
so early measures are indicated for the prevention of obesity.
One have to chick his weight in a suitable periods of time and when an
increase of weight is noted one have to limit or decrease some of the
unnecessary food such as sugars, cream, butter and others.
Also it is important to decrease food for everybody at the late twenties
and foreword. At the same time an increase in the exercise such as
walking and sports is necessary.
Treatment:
1- By Food Control:
Since adipose tissues are stores for excess energy, then the calorie
intake must be below the actual daily needs and so one think to
reduce the quantity of diet taken to less than the actual need.
Since carbohydrates and fats constitute the greatest source of
calories in the diet so they must be reduced, some prefer to reduce
fat to minimum and keeping normal amount of carbohydrate while
others prefer the reduction of both fats and carbohydrates equally.
2- By excise:
Exercise is required and it is very necessary to decrease weight or
to burn the energy. One should follow a regular exercise or at least
increase walking or swimming or other sports.
3- By drugs:
a. Amphetamine and its derivatives: They depress the appetite
and stimulate metabolism and help to burn the excess fat.
However it has many side effects.
b. Thyroxin: It stimulates metabolism. This help in decreasing
weight. However it is contra indicated except in those rare cases
of obesity associated with evidence of hypothyroidism.
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c. Methyl Cellulose: This is indigestible substance add bulk to the
diet it is a harmless substance.
d. Fenfluramin hydrochloride (Ponderax): It decreases the
felling of hunger in addition it helps in metabolizing food and
burns fats.
e. Mazindol (Teronac): It is another drug for the treatment of
obesity and it has similar effects to Ponderax but has fewer side
effects than Ponderax.
f. Orlistat (Xenical): It is the latest drug used for the treatment of
obesity. It is a specific and reversible inhibiter of
gastrointestinal lipases. Thus lipase become unable to hydrolyze
dietary fat in the form of TG
Underweight:
Weight more than 10% lower than ideal is usually considered to be
abnormal especially in persons less than 25 years and is usually require
medical investigation.
Underweight may be due to an inadequate energy intake or to excessive
body activity or it may be familiar.
Diseases such as malignancy, G.I.T. disorders, chronic infectious diseases
or endocrine disturbances such as hyperthyroidism may be causes of
progressive weight loss.
Underweight due to an inadequate caloric intake may be a serious
condition especially in the young as resistance to infections particularly to
TB may be lowered.
Also the occurrence of the complications of pregnancy in young women
may result from malnutrition due to an inadequate energy intake.
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