Obesity
Content
OBESITY
1. Define the components of body weight in terms of:
Fat Mass – combines the fat from all body sources, including fat in the brain; skeleton and adipose tissue.
Lean Body Mass – is the part of the body free of adipose tissue and includes the skeletal muscles, water, bone and small
amount of essential fat in the internal organs, bone marrow and nerve tissues.
2. Differentiate Essential Fat from Storage Fat:
Essential fat – the body fat located in specific sites that is necessary for survival; about 3% to 12% of body weight.
Necessary for normal physiologic functioning, is stored in small amounts in the bone marrow, heart, lung,
liver, spleen, kidneys, muscles and lipid-rich tissues in the nervous system.
In men, about 3% of body fat is essential. In women, essential fat is higher about 12% because it includes
sex specific body fat in the breasts, pelvic regions and thighs.
Storage fat - the fat that accumulates under the skin and around internal organs
Protects internal organs from trauma and is considered “expendable”
The primary energy reserve of the body is the fat stored as triglyceride in depots made up of adipose
tissue
3. Factors Regulating energy intake and Body weight
a. Thermogenesis and thermogenic effect of food
The TEF is made up of an obligatory component related to the energy value of the food consumed and an additional
adaptive component that presumably responds to overeating by eliminating the excessive energy in the form of heat.
b. Resting metabolic Rate
When the body is suddenly deprived of adequate energy, such as with involuntary or deliberate starvation or semi
starvation, the RMR adapts to conserve energy against an unpredictable future by dropping rapidly. When adequate
food intake is restored, the RMR returns to baseline levels.
c. Energy Expended in Voluntary Activity
d. Brain Neurotransmitters
Norepinephrine and Dopamine - are released by the sympathetic nervous system in response to dietary intake.
Mediate the activity of areas in the hypothalamus that govern feeding behavior.
Fasting and semi starvation lead to decreased SNS activity and increased adrenal medullary activity with a
consequent increase in epinephrine, which fosters substrate mobilization.
= Decreases in serotonin and increases in neuropeptide Y have been associated with an increase in CHO appetite.
= the level of neuropeptide Y increases during food deprivation = increase in appetite after dieting.
= Preferences and cravings for sweet high fat foods observed among obese and bulimic patients may involve the endorphin
system
Cortocotropin-Releasing Factor =is produced in the brain and is involved in controlling adenocorticotropic hormone release
from the pituitary gland.
A potent anorexic agent, it decreases food intake on its own and weakens the feeding response produced
by norepinephrine and neuropeptide Y.
e.
Gut peptides
Cholecystokinin (CCK) – released when fats and proteins reach the small intestine
Causes the gall bladder to contract and stimulates the pancreas to realese enzymes. At the brain level,
CCk inhibits food intake
Bombesin - reduces food intake and enhances the release of CCK
Enterostatin – involves in the satiety following the consumption of fat.
Apolipoprotein A-IV – is synthesized and secreted in the small intestine in the process of the lymphatic secretion of
chylomicrons; suppresses food consumptioN
f. Hormones
Thyroid Hormones – modulate the tissue responsiveness to the catecholaines secreted by the SNS
=
in T3 lowers the response to SNS activity and diminishes adaptive thermogenesis = predispose to obesity and
weight gain
INSULIN – acts in the CNS and the PNS to regulate food intake.
= its effect on the CNS is to inhibit intake while in the periphery.
=impaired insulin leads to SNS activity and thus to impaired thermogenesis.
= the greater the insulin resistance, the lower the TEF.8
LEPTIN – secreted by the adipose tissue that is correlated with the percent of body fat; weight loss is associated with a
reduction in leptin.
RESISTIN - antagonizes insulin action
GHRELIN – a hormone produced primarily by the stomach, acts on the hypothalamus to stimulate feeding and on other
tissues to slow metabolism and reduce fat oxidation.
Numbers: 4&5 Overweight – is a state in which weight exceeds a standard based on height
Obesity – is a condition of excessive fatness
Classification
BMI kg/m2
Underweight
<18.5
Normal
18.5-24.9
Overweight
25-29.9
Obesity, Class 1
30-34.9
Obesity, class II
35-39.9
Extreme, Class III
>40
6. GOALS OF TREATMENT:
a. Rate and extent of weight loss
- loss of both protein and fat in amounts determined to some degree by the rate of weight reduction
- Steady weight loss over a long period favors reduction of fat stores, limits the loss of vital protein tissues and avoids the
sharp decline of RMR that accompanies rapid weight reductyion
- a drastic reduction in calories resulting in a high rate of weight loss can imic the starvation response
b. Dietary Modification
- integrated with food-choice changes, exercise, frequent behavior modification, nutritional education and psychological support
C. Behavior modifications:
- lifestyle modifications
1. Define the components of body weight in terms of:
Fat Mass – combines the fat from all body sources, including fat in the brain; skeleton and adipose tissue.
Lean Body Mass – is the part of the body free of adipose tissue and includes the skeletal muscles, water, bone and small
amount of essential fat in the internal organs, bone marrow and nerve tissues.
2. Differentiate Essential Fat from Storage Fat:
Essential fat – the body fat located in specific sites that is necessary for survival; about 3% to 12% of body weight.
Necessary for normal physiologic functioning, is stored in small amounts in the bone marrow, heart, lung,
liver, spleen, kidneys, muscles and lipid-rich tissues in the nervous system.
In men, about 3% of body fat is essential. In women, essential fat is higher about 12% because it includes
sex specific body fat in the breasts, pelvic regions and thighs.
Storage fat - the fat that accumulates under the skin and around internal organs
Protects internal organs from trauma and is considered “expendable”
The primary energy reserve of the body is the fat stored as triglyceride in depots made up of adipose
tissue
3. Factors Regulating energy intake and Body weight
a. Thermogenesis and thermogenic effect of food
The TEF is made up of an obligatory component related to the energy value of the food consumed and an additional
adaptive component that presumably responds to overeating by eliminating the excessive energy in the form of heat.
b. Resting metabolic Rate
When the body is suddenly deprived of adequate energy, such as with involuntary or deliberate starvation or semi
starvation, the RMR adapts to conserve energy against an unpredictable future by dropping rapidly. When adequate
food intake is restored, the RMR returns to baseline levels.
c. Energy Expended in Voluntary Activity
d. Brain Neurotransmitters
Norepinephrine and Dopamine - are released by the sympathetic nervous system in response to dietary intake.
Mediate the activity of areas in the hypothalamus that govern feeding behavior.
Fasting and semi starvation lead to decreased SNS activity and increased adrenal medullary activity with a
consequent increase in epinephrine, which fosters substrate mobilization.
= Decreases in serotonin and increases in neuropeptide Y have been associated with an increase in CHO appetite.
= the level of neuropeptide Y increases during food deprivation = increase in appetite after dieting.
= Preferences and cravings for sweet high fat foods observed among obese and bulimic patients may involve the endorphin
system
Cortocotropin-Releasing Factor =is produced in the brain and is involved in controlling adenocorticotropic hormone release
from the pituitary gland.
A potent anorexic agent, it decreases food intake on its own and weakens the feeding response produced
by norepinephrine and neuropeptide Y.
e.
Gut peptides
Cholecystokinin (CCK) – released when fats and proteins reach the small intestine
Causes the gall bladder to contract and stimulates the pancreas to realese enzymes. At the brain level,
CCk inhibits food intake
Bombesin - reduces food intake and enhances the release of CCK
Enterostatin – involves in the satiety following the consumption of fat.
Apolipoprotein A-IV – is synthesized and secreted in the small intestine in the process of the lymphatic secretion of
chylomicrons; suppresses food consumptioN
f. Hormones
Thyroid Hormones – modulate the tissue responsiveness to the catecholaines secreted by the SNS
=
in T3 lowers the response to SNS activity and diminishes adaptive thermogenesis = predispose to obesity and
weight gain
INSULIN – acts in the CNS and the PNS to regulate food intake.
= its effect on the CNS is to inhibit intake while in the periphery.
=impaired insulin leads to SNS activity and thus to impaired thermogenesis.
= the greater the insulin resistance, the lower the TEF.8
LEPTIN – secreted by the adipose tissue that is correlated with the percent of body fat; weight loss is associated with a
reduction in leptin.
RESISTIN - antagonizes insulin action
GHRELIN – a hormone produced primarily by the stomach, acts on the hypothalamus to stimulate feeding and on other
tissues to slow metabolism and reduce fat oxidation.
Numbers: 4&5 Overweight – is a state in which weight exceeds a standard based on height
Obesity – is a condition of excessive fatness
Classification
BMI kg/m2
Underweight
<18.5
Normal
18.5-24.9
Overweight
25-29.9
Obesity, Class 1
30-34.9
Obesity, class II
35-39.9
Extreme, Class III
>40
6. GOALS OF TREATMENT:
a. Rate and extent of weight loss
- loss of both protein and fat in amounts determined to some degree by the rate of weight reduction
- Steady weight loss over a long period favors reduction of fat stores, limits the loss of vital protein tissues and avoids the
sharp decline of RMR that accompanies rapid weight reductyion
- a drastic reduction in calories resulting in a high rate of weight loss can imic the starvation response
b. Dietary Modification
- integrated with food-choice changes, exercise, frequent behavior modification, nutritional education and psychological support
C. Behavior modifications:
- lifestyle modifications
