Nutrition 7

ThiQar college of MedicineFamily & Community medicine dept.

Nutrition L7, 3rd stage/onlineby: Dr. Muslim N. SaeedMay 20th ,2021

Obesity

Overview
Assessment
Demographics
Determinants of Obesity
Medical Complications

Assessment

The primary parameter used to categorize weight is BMI:
BMI= body Wt.(Kg) / squared Ht. in meters
-18.5 and 24.9 is normal in adults
-25 to 29.9 is overweight
-30 to 34.9 is class I obesity, 35 to 39.9 is class II obesity.
Class III, “severe,” or “extreme” obesity is 40 and higher. Calculated from height and weight and expressed in kg/m2.


BMI is a recommended parameter to assess obesity, but an imperfect tool to measure adiposity (example greater lean body mass rather than adiposity in muscular individuals).

Demographics

1- Gender Differences:
Men are more likely than women to be overweight, whereas women are more likely to be obese.
Men, however, are more likely to have central obesity, associated with greater health risks.
2- Race and Ethnic Origin
3- Socioeconomic Status: The prevalence ranges from approximately 2% in the least developed countries to over 30% in the most developed countries.
4- Education Level:
Education level is inversely related to the risk of obesity.

5- Rural and Urban Differences:

the prevalence of obesity is greater in rural than urban areas. Factors that reduce physical activity may play a role.
6- Age:
The incidence of overweight increases steadily after age 20 until the seventh decade of life.

Determinants of Obesity

1. Genetic Factors
Most of the genetic influence on obesity is poly-genic. Single-gene mutations related to obesity often involve leptin and melano-cortin.
2. Modulation of Appetite
Many hormonal factors are involved in appetite, as well as in the absorption, storage, and use of calories.
Factors providing input to the brain include leptin levels, vagal activity, and fluctuation in plasma glucose levels.


3. Lifestyle Influences:
obesity develops when caloric intake exceeds caloric expenditure against a background of genetic influences.
The chief determinants of energy imbalance are lifestyle factors.
Individual total energy requirements depend on the basal metabolic rate (BMR), thermic effect of food, and energy needed for the day’s physical activities.

4. Caloric Intake:

-tendency to consume more calories needed.
-Some of this increase is related to increased portion size.
-The frequency of meals may play a small role. Eating smaller meals more frequently is associated with less overweight.
-Large meals are associated with more insulin release.

5. Activity Changes

Decreased energy expenditure may play a greater role in the development of obesity than increased caloric intake.
6. Medications
A number of medications are associated with weight gain, including antidepressants, antipsychotics, anticonvulsants, and hypoglycemic agents.
Tricyclic antidepressants, systemic steroid use can cause a cushinoid type of obesity.

-Insulin, as well as oral hypo-glycemics that increase production or release of insulin, promote weight gain.
-Metformin, is associated with modest weight loss.


7. Endocrine and Metabolic Factors
Specific endocrine or metabolic disorders known to cause obesity account for less than 1% of the obese population.
A. Hypothyroidism
-in children, associated with slow statural growth and developmental delay.
-More common among adults and more often seen in women, hypothyroidism is a relatively rare cause of obesity.

B. Cushing’s Syndrome

This endocrine disorder is associated with central obesity.
C. Polycystic Ovary Syndrome
More than 50% of women affected by this relatively common disorder are obese.
Insulin resistance is a consistent finding, even in the absence of obesity.

D. Growth Hormone Deficiency

Although growth in height is impaired in growth hormone deficiency, there is also an increase in truncal obesity.

Medical Complications of obesity

1. Hypertension
The obesity-related to increase in blood pressure is associated with an increase in vascular resistance. Weight loss is the most effective lifestyle change to decrease blood pressure.
2. Dyslipidemia
Obesity is associated with elevated TG levels, reduced HDL , and an increase in LDL.


3.Type 2 Diabetes Mellitus
The risk of T2DM is low below a BMI of 22 to 23 kg/m2. For men, the risk of Type 2 DM above a BMI of 35 kg/m2 increased 60-times. Up to 80% of cases of T2DM can be attributed to overweight and obesity.
Weight loss is recommended to lower glucose levels in overweight and obese persons with T2DM.
4. Metabolic Syndrome
The metabolic syndrome brings together a number of the comorbidities associated with obesity.

5. Heart Disease

The presence of obesity lead to cardiomyopathy and congestive heart failure (CHF) as the workload of the heart increases.
6. Cancer
Obesity may be associated with Cancers of the esophagus, colon, kidney, gallbladder, and pancreas.
Also, increased risk of prostate, gastric, ovarian, and endometrial cancers.

7. Pulmonary Disease

Obesity can have an impact on overall lung function, It increases the work of breathing.
Obesity increases pressure on the diaphragm, reducing lung function.
Asthma is exacerbated with increased weight.
About 70% of Obstructive Sleep Apnea patients are obese.
8. Fatty Liver Disease
fatty liver disease is first described in obese females.

9. Orthopedic Disorders

Overweight children have an increased risk genu valgus, and scoliosis.
In adults, degenerative joint disease, is related in part to mechanical factors resulting in increased compressive forces on the knee.
10. Gallbladder Disease
Obesity, is a risk factor for gallbladder disease, because cholesterol production increases with weight gain, and cholesterol is excreted into bile.

11. Psychological Impact

Self-awareness of overweight and the associated psychological impact can be seen in children and can result in poor self-esteem.
Also, his may result in poor body image, especially in young women.
In adults, obesity is associated with depression in women.

End