What are overweight and obesity?

Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health.

The ratio of height to weight.

Body mass index (BMI) is a simple index of weight-for-height that is commonly used to classify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of his height in meters (kg/m²). For adults, WHO defines overweight and obesity as follows:

	Overweight:	BMI ≥ 25
	Obesity:	BMI ≥ 30

Data & statistics in America

According to National Center for Health Statistics' (NCHS) report

• More than one-third (36.5%) of U.S. adults have obesity. 
• Obesity-related conditions include heart disease, stroke, type 2 diabetes and certain types of cancer, some of the leading causes of preventable death.
  
• The estimated annual medical cost of obesity in the U.S. was $147 billion in 2008 U.S. dollars; the medical costs for people who are obese were $1,429 higher than those of normal weigh
  
• Obesity is higher among middle age adults age 40-59 years (40.2%) and older adults age 60 and over (37.0%) than among younger adults age 20–39 (32.3%).
  

Causes of obesity and overweight

• Lack of energy balance: take in more calories than you use.
• An inactive life: spend too much time in front of TVs and computers, or rely on cars instead of walking
• Genes and family history: Studies of identical twins who have been raised apart show that genes have a strong influence on a person's weight.

Excess Weight Raises Your Risk of Many Health Problems
• Health conditions: Some hormone problems may cause overweight and obesity, such as hypothyroidism, Cushing's syndrome, and polycystic ovarian syndrome (PCOS).
• Medicines: for example, some corticosteroids, antidepressants, and seizure medicines.
• Emotional factors: Some people eat more than usual when they're bored, angry, or stressed. 
• Lack of sleep: People who sleep fewer hours also seem to prefer eating foods that are higher in calories and carbohydrates, which can lead to overeating, weight gain, and obesity.
• Age: As you get older, you tend to lose muscle, especially if you're less active. Muscle loss can slow down the rate at which your body burns calories. Many women gain about 5 pounds during menopause and have more fat around the waist than they did before.

Weight loss treatments

• Orlistat: It a medicine used to block some of the fat that you eat, keeping it from being absorbed by your body for weight loss. It must be used together with a reduced-calorie diet. Commonly reported side effects of orlistat include: bowel urgency, frequent bowel movements, oily evacuation, oily rectal leakage, steatorrhea, and flatulence with discharge. Other side effects include fecal incontinence.
• Liposuction: While liposuction is often portrayed as an operation where large amounts of fat are sucked out of the body, it is not used for major weight loss -- only for toning certain areas by removing some fat. 
• Gastric bypass surgery: It is a surgery that helps you lose weight by changing how your stomach and small intestine handle the food you eat. The disanvantages associated include

  		Costly: The aveage cost is $25,571 in 2015.
  		Risks: All surgical procedures carry risks. Your surgeon will explain all potential complications such as anesthesia-related risks, posible infection, and ulcer.
  		Side effects: such as acid reflux, obstruction of stomach, bowel obstruction, inability to eat certain foods, dhronic nausea and vomiting.