When someone has had part of the stomach removed, the stomach cannot hold as much food as before. If all of the stomach has been removed, food is broken down in the small intestine instead of the stomach.

After any type of stomach surgery, eating and drinking can make you feel full quite quickly. So it is a good idea to have several small meals and snacks during the day, rather than a few larger meals. It’s also best to have drinks separately from meals (or just drink a small amount with your meals).

You will probably lose some weight before your operation. It is important to go back to a balanced diet as soon as possible. This can help you to gain weight, and recover more quickly. You may not feel much like eating for some time after the operation, so don't be worried if it takes you a couple of months to get back to eating a balanced diet again. You may find that certain foods make you feel sick, or give you indigestion or diarrhoea, and you will begin to know which foods you should avoid. However, it is important to keep trying to build up your strength.

If you are still losing weight you will need to increase your calorie and protein intake. A good way of doing this is by having nutritious, high-calorie drinks. There are several different types and they are available on prescription from your doctor or you can buy them at most chemists. You could carry 'nibbles' in your pocket or handbag at all times. Another way of improving your appetite is to have a glass of sherry (or another type of alcoholic drink) about half an hour before a meal – but check with your doctor first as some medicines should not be mixed with alcohol.

It can be very helpful to talk to a dietitian before, or soon after, your operation. They can give advice and information about possible changes to your diet. Most hospitals have a dietitian available and the staff on the ward can arrange for them to visit you. Your GP may also be able to refer you to a community-based dietitian.

After your operation your doctor may prescribe an injection of vitamin B12 for you every few months. This is because it is difficult to absorb this vitamin from food once all or part of your stomach has been removed.

You may find it helpful to read our sections on diet and cancer and dietary problems after surgery.

After an operation on your stomach you may have an effect called dumping syndrome. After meals, your stomach may empty quickly, which leads to a drop in blood sugar and fluid draining into your intestine. If this happens you will feel faint and weak, and you may sweat and look pale. The effect usually lasts between 30 minutes and two hours.

To avoid dumping syndrome that occurs soon after eating, it is helpful to eat foods that are high in starch. These include white bread, potatoes, rice and pasta.

You should avoid foods such as raw sugars, chocolate and sugary drinks, which are full of easily absorbed sugar.

If the dumping syndrome happens a few hours after eating, it can help to eat small, high-protein meals frequently (foods like meat, fish or cheese). Your doctor can also prescribe medicines to help this. In most people the dumping syndrome settles after a while, but let your doctor or dietitian know if it continues to be a problem.