Some people consider surgery for weight loss or have it recommended to them, because of issues with obesity that can already result in poor health or a problematic standard of living. Weight loss surgery offers a way to address or deal with obesity, but in a more straightforward way which doesn't require as much time or lifestyle change in order for it to work. That said, this type of medical procedure still comes with its share of risks and potential adverse effects, so it isn't a decision that should be taken lightly.
Many types of surgeries work on a person by creating a physical or other limit to the volume of food that the person can eat. So instead of that person having the usual volume within which to accept and digest food, that volume is significantly limited so that even if the patient wishes to continue eating the way he did before, this becomes a much more difficult thing to do.
One thing to consider carefully is the fact that this surgery affects a very important part of how your body functions. Whether the surgery makes your stomach smaller, or whether it makes it less likely that you will digest or absorb food, your digestive process will never be the same. You will have to get used to the fact that you will be seeing your doctor regularly, maybe for the rest of your life, in order to monitor whether your new level of digestion and absorption is proving to be sufficient for a healthy life.
You will also have to remember that while the surgery makes it more difficult to regain weight, this isn't impossible. Don't expect to be able to live an unhealthy life and get away with it, because you've had the surgery. Get used to the idea that you will still be expected to make healthy lifestyle changes anyway, involving the kind of food you eat and the amount of activity you do. Otherwise, over time you may find that weight will continue to be a problem. You can ask your doctor about these and other concerns when you discuss your surgical options. Usually, if surgery is being advised, the patient has already reached the point where the good that the surgery could accomplish already outweighs the risks involved.