Obesity is excess body weight, defined as a body mass index (BMI) of ≥ 30 kg/m2

Obesity Disorder is a complications include cardiovascular disorders (particularly in people with excess abdominal fat), diabetes mellitus, certain cancers, cholelithiasis (the formation of gallstones), fatty liver, cirrhosis, osteoarthritis, reproductive disorders in men and women, psychologic disorders, and, for people with BMI ≥ 35, premature death

Diagnosis for Obesity Disorder:

  • BMI
  • Waist circumference
  • Sometimes body composition analysis

In adults, BMI, defined as the weight (kg) divided by the square of the height (m2), is used to screen for overweight or obesity.

BMI of 25 to 29.9 kg/m2 indicates overweight;

BMI of ≥ 30 kg/m2 indicates obesity

The waist circumference that increases the risk of complications due to obesity varies by ethnic group and sex:

  • Men: > 78 cm (> 30.7 in), particularly > 90 cm (> 35.4 in)
  • Women: > 72 cm (> 28.3 in), particularly > 80 cm (> 31.5 in)

Causes for Obesity Disorder:

Environmental factors:

Weight is gained when caloric intake exceeds energy needs. High-calorie foods (eg, processed foods), diets high in refined carbohydrates, and consumption of soft drinks, fruit juices, and alcohol promote weight gain. Diets high in fresh fruit and vegetables, fiber, and complex carbohydrates, with water as the main fluid consumed, minimize weight gain. A sedentary lifestyle promotes weight gain.

 

Regulatory factors:

Prenatal maternal obesity, prenatal maternal smoking, and intrauterine growth restriction can disturb weight regulation and contribute to weight gain during childhood and later. Obesity that persists beyond early childhood makes weight loss in later life more difficult.

About 15% of women permanently gain ≥ 9 kgs with each pregnancy.

Insufficient sleep (usually considered < 6 to 8 h/night) can result in weight gain by changing the levels of satiety hormones that promote hunger.

Drugs, including corticosteroids, lithium, traditional antidepressants (tricyclics, tetracyclic, monoamine oxidase inhibitors [MAOIs]), benzodiazepines, and antipsychotic drugs, can cause weight gain

Uncommonly, weight gain is caused by one of the following disorders:

  • Brain damage caused by a tumor (especially a craniopharyngioma) or an infection (particularly those affecting the hypothalamus), which can stimulate consumption of excess calories
  • Hyperinsulinism due to pancreatic tumors
  • Hypercortisolism due to Cushing syndrome, which causes predominantly abdominal obesity
  • Hypothyroidism (rarely a cause of substantial weight gain)

Eating disorders:

At least 2 pathologic eating patterns may be associated with obesity:

Binge eating disorder is the consumption of large amounts of food quickly with a subjective sense of loss of control during the binge and distress after it. This disorder does not include compensatory behaviors, such as vomiting. Prevalence is 1 to 3% among both sexes and 10 to 20% among people entering weight reduction programs. Obesity is usually severe, large amounts of weight are frequently gained or lost, and pronounced psychologic disturbances are present.

Night-eating syndrome consists of morning anorexia, evening hyperphagia, and insomnia. At least 25 to 50% of daily intake occurs after the evening meal. About 10% of people seeking treatment for severe obesity may have this disorder. Rarely, a similar disorder is induced by the use of a hypnotic such as zolpidem.

For example, nocturnal eating contributes to excess weight gain in many people who do not have the night-eating syndrome.

 

Risk of obesity persisting into adulthood depends partly on when obesity first develops:

During infancy: Low risk

  • Between 6 mo and 5 yr: 25%
  • After 6 yr: > 50%
  • During adolescence, if a parent is obese: > 80%

 

Risk of complications depends on

  • Body fat distribution (increasing with a predominantly abdominal distribution)
  • Duration and severity of obesity
  • Associated sarcopenia (It is the loss of muscle mass and coordination that results from the process of aging. )

Treatment for Obesity Disorder:

  • Dietary management
  • Physical activity
  • Behavioral interventions
  • Drugs (eg, orlistat, lorcaserin, phentermine/topiramate)
  • Bariatric surgery

Diet:

Balanced eating is important for weight loss and maintenance.

Strategies include

  • Eating small meals and avoiding or carefully choosing snacks
  • Substituting fresh fruits and vegetables and salads for refined carbohydrates and processed food
  • Substituting water for soft drinks or juices
  • Limiting alcohol consumption to moderate levels
  • Including no- or low-fat dairy products, which are part of a healthy diet and help provide an adequate amount of vitamin D

Prescription contains:

Orlistat, lorcaserin, phentermine/topiramate
  • Orlistat: A dose of 120 mg thrice daily should be taken with meals that include fat. A vitamin supplement should be taken at least 2 h before or after taking orlistat.
  • The usual and maximum dose of lorcaserin is 10 mg every 12 h.
  • Phentermine is a centrally acting appetite suppressant for short-term use ( ≤ 3 mo). The usual starting dose is 15 mg once/day, and dose may be increased to 30 mg once/day, 37.5 mg once/day or 15 mg twice a day.
  • Combination of phentermine and topiramate (used to treat seizures and migraines) results in weight loss for up to 2 yr.
  • The starting dose of the extended-release form (phentermine 3.75 mg/topiramate 23 mg) can be increased to 7.5 mg/46 mg after 2 wk, then gradually increased to a maximum of 15 mg/92 mg if needed to maintain weight loss.
  • Lorcaserin suppresses appetite via selective agonist of serotonin 2C (5-HT2C) brain receptors. The usual and maximum dose of lorcaserin is 10 mg oral for every 12 h.