Obesity is determined by measuring body weight and fat. There are different ways of calculating body fat. Body mass index (BMI) is one of the best methods used to measure body fat. BMI is calculated as the ratio of the weight in Kg and height in square metre. Guidelines define overweight as a BMI between 25 and 29.9 kg/square meter and obesity as a BMI greater than 30. The doctor may also suggest blood test for sugar, cholesterol, and triglycerides. In case insufficient thyroid functioning (hypothyroidism) is suspected, the doctor will ask for a thyroid stimulating hormone test.
ariatric surgery (“weight loss surgery”) is the use of surgical interventions in the treatment of obesity. As every operation may have complications, surgery is only recommended for severely obese people who have failed to lose weight with dietary modification and pharmacological treatment. Weight loss surgery relies on various principles; the most common approaches are reducing the volume of the stomach, producing an earlier sense of satiation (e.g. by adjustable gastric banding and vertical banded gastroplasty) and reduce the length of bowel that food will be in contact with, directly reducing absorption (gastric bypass surgery). Band surgery is reversible, while bowel shortening operations are not. All the procedures can be performed laparoscopically. Surgery for severe obesity is associated with long-term weight loss and decreased overall mortality. A marked decrease in the risk of diabetes mellitus, cardiovascular disease and cancer has also been found after bariatric surgery. Weight loss is marked in the first few months after surgery and is sustained in the long term. When the two main techniques are compared gastric bypass procedures are found to lead to 30% more weight loss than banding procedures one year after surgery.