nutrition

Obesity

is a state of excess adipose tissue mass.
BMI ≥30 obesity
BMI ≥ 25 overweight

abdominal (android or apple-shaped) obesity

generalized (gynoid or 'pear-shaped)
obesity

Obesity

Many complications of obesity, as insulin resistance, diabetes, hypertension, hyperlipidemia, are linked more strongly to intraabdominal than to overall adiposity.

Obesity

Prevalence

30.5% American adult population had obesity

64% of U.S. adults were overweight
4.7% of the population Extreme obesity

Obesity is more common in women and in the poor.

Factors control the appetite

Factors released from the adiposity tissue

Obesity
Etiology

The environmental factors

plays a key role in obesity

Evidence

Famine protect against obesity
Recent and rapid increase in the prevalence of obesity



Obesity
Factors increase prevalence
Increasing energy intake
↑ Portion sizes
↑ Snacking and loss of regular meals
↑ Energy-dense food (mainly fat)
↑ Affluence
Decreasing energy expenditure
↑ Car ownership
↓ Walking to school/work
↑ Automation; ↓ manual labour
↓ Sports in schools
↑ Time spent on video games and watching

Obesity

The genetic factors
genes influence the susceptibility to obesity

Evidence:

Obesity is commonly seen in families
identical twins have very similar BMIs
Obesity is part of specific genetic syndromes (Laurence-moon biedl)


Obesity
Gene mutation detected
ob gene coding the peptide leptin.
High leptin levels decrease food intake
increase energy expenditure.

Db gene coding leptin receptor.(leptin resistant)

POMC coding proopiomelanocortin ( neuropeptides)

Obesity

To date, there is no evidence to suggest that mutations in the leptin or leptin receptor genes play a prominent role in common forms of obesity

Obesity

Secondary causes (reversible)
Endocrine factors
Hypothyroidism
Hypothalamic tumours or injury
Cushing's syndrome
Insulinoma
Drug treatments
Corticosteroids
Tricyclic antidepressants
Sulphonylureas
Sodium valproate
Oestrogen-containing contraceptive pill
β-blockers


Obesity
Complications
Obesity is associated with an increase in mortality, mostly due to cardiovascular causes
Mortality rates rise as obesity increases
Obesity related 300,000 deaths per year.
Life expectancy shortened by( 2–5 years) moderately obese
BMI > 45 may lose 13 years of life.

Obesity

• Complications
• Metabolic complications:
Insulin resistance, diabetes type 2, hyperlipidemia
• Most obese individuals do not develop diabetes.
• 80% of patients with type 2 diabetes mellitus are obese
• Increase the risk coronary heart disease, Stroke

Obesity

Metabolic syndrome
Central obesity: waist circumference ≥ 94 cm (male)
≥ 80 cm (female)
AND any two of the following
< 50 mg/dL in females
systolic BP > 130 or diastolic BP >85 mm Hg
Raised fasting plasma (FPG): >100 mg/dL or previously diagnosed type 2 diabetes


Obesity
2. Cardiovascular Disease
coronary disease
stroke
congestive heart failure (CHF)
atherogenic lipid profile
increase (LDL) ,VLDL, and triglyceride.
decreased HDL
Hypertension
increased peripheral resistance, cardiac output
increased sympathetic nervous system tone
increased salt sensitivity, and insulin-mediated salt retention

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© 2005 Elsevier

Obesity

3. Endocrine Disorders :
In men :
plasma testosterone often reduced
estrogen levels increased
Gynecomastia may be seen.
In women:
menstrual abnormalities
increased androgen
increased conversion of androgen to estrogen.
oligomenorrhea
polycystic ovarian syndrome (PCOS)

Obesity

4. Pulmonary Disease:
Exertional dyspnoea Sleep apnoea Respiratory failure (Pickwickian syndrome)

caused by (restrictive ventilation)
reduced chest wall compliance
decreased functional residual capacity and expiratory reserve volume


Obesity
5. Gastrointestinal :
Gallstones: cholesterol gallstones
caused :
enhanced biliary secretion of cholesterol
supersaturation of bile

nonalcoholic fatty liver disease :
simple steatosis
steatohepatits
cirrhosis
Gastroesophageal reflux disease:

Obesity

6. Musculoskeletal : increased risk of osteoarthritis

7.Skin :

Skin infection (submammary Candida)
varicose vein

8. cancer: colorectal CA, uterine CA, breast CA

9. Psychological : depression, Social stigmatization

10. Socioeconomic : low income, unemployment

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