Bariatric (Obesity) surgery is an option in severely obese patients, where lifestyle modification, exercise regimes or medications have been tried but found not to be effective.
Bariatric surgical procedures are an option for treating severe obesity, by reducing intake or absorption of calories. There are various procedures, all of which have been effective depending on patients profile. Bariatric surgery should always be performed in a specialist centre, and long-term follow-up of patients is necessary.
Here's a very simple explanation of how you will lose weight with surgery. Your body needs energy to function and your energy source is the food that you eat. A normal weight person successfully balances their energy intake (food eaten) with their energy requirements (daily activity).
In other words, they burn up all the energy provided by the food they eat, and stay slim. However, you begin to get fatter when you eat more food than you need for your energy requirements.
Over a long period of time the excess gets stored as fat around your body. In theory, eating just just 100 calories a day more than you need would lead to a weight gain of 5 kgs per year.
Do that for 10 years and you could gain 100 lbs or 45kg! A person who is roughly 30kg (65lbs) or more above his / her ideal weight is considered to be severely obese. However, obesity is a complex condition and not simply caused by overeating.
In fact, many people eat more calories than they need, but not everyone stores the excess as fat. There seems to be some sort of in–built mechanism that causes excessive fat storage in some people, and scientists are working to try and understand more about it. Severe obesity tends to run in families so there is likely to be a genetic component as well.
Weight loss will only happen when your body has to burn up the stored fat to provide your energy. In other words, when your body's energy needs are greater than that provided by the food you eat.
The changes brought about by weight loss surgery are a 'tool' to restrict your energy intake so that you will burn up your fat stores. Weight loss surgery is almost guaranteed to help you lose weight, but like all good tools, it works best in the hands of a worker (you) who is well trained!