Asked Questions

Dietician Advice After Surgery

After surgery, you can eat much smaller amounts at a time, and you need to learn a whole new eating pattern. To avoid shortcomings, it is incredibly important to follow the recommendations given by the dietitian to the planned controls. Beneath you will find dietary information and guidelines you should follow after surgery.

It is not recommended to switch to the next dietary period before time as there will be a risk of complications. The new smaller stomach should have enough time to get used to new foods.

Protein beverages can be consumed in a variety of ways. They can be diluted with milk or juice. They can be blended with fruit in a smoothie and they can be frozen and eaten as ice cream. Do not omit protein supplements as protein is important for maintaining and building muscles, tissues and organs.

You can replace milk with:

Sugar-free cocoa milk

Low fat yoghurt and light yoghurt drinks

Lactose free milk

Soy milk (beware of sugar content in the vanilla and cocoa variety)

It is common to experience reduced appetite. When you cannot eat enough, it’s most important that you prioritize the proteins first – protein drink, milk, yogurt, cheese, meat, poultry, fish. Protein is the body’s building blocks and is necessary to maintain and build up muscles, tissues and organs.

Alcohol is not recommended during the first period after surgery. It reduces the risk of complications and negative side effects. In addition, many people experience rapid onset of alcohol after surgery because alcohol soon reaches the small intestine, and therefore absorbs faster than before surgery. Drink accordingly and try small amounts in a safe environment to test how much you can withstand. Alcohol also contains many calories and should therefore be limited.

After the operation you may drink fluids right before the meal and no earlier than 30 minutes after. Drinking during meals will make the food pass through the stomach faster, which can lead to weight gain as you will soon be hungry again. Drinking during meals can also cause discomfort. Patients with smaller appetites or who are struggling to reduce weight loss will in some cases be advised to drink during meals, if it helps them to eat more calories. 

The desire for sweet stuff can return. The operation is an opportunity to establish new. As sweets contain many kcal, excessive intake can lead to a reduction in weight loss or even weight gain. When craving sweets, consider instead kcal-reduced candy, fruit, sugar-free pastilles, chewing gum, etc.

You can use different apps on your android or iPhone e.g. “Lifesum” or “My Fitness Pal”.

Many people experience issues with drinking water. Often it may help to add a little “acid” such as lemon, lime or orange slices. It also helps if the water is in the form of coffee, tea or sugar-free juice.

Vitamins & Minerals After Surgery

Particularly after a gastric bypass there is a risk that vitamins, minerals and proteins may be lacking because you absorb less of this after reassembling your intestines. It is especially iron, Vitamin B, Lime, Vitamin D and Zinc that are affected. It is therefore very important that you follow the dietician’s recommendations and get the necessary blood samples for the rest of your life. In order to avoid shortcomings, we recommend that you further supplement with multi-vitamin mineral tablets, iron tablets, vitamin D and vitamin B12. You will be advised about the choice of preparation and will be given the necessary prescriptions. Your vitamin and mineral status must be checked for the rest of your life with regular blood tests. 

After surgery, you can eat much smaller amounts at a time, and you need to learn a whole new eating pattern. To avoid shortcomings, it is incredibly important to follow the recommendations given by the dietitian to the planned controls. Beneath you will find dietary information and guidelines you should follow after surgery.

Iron deficiency is the most common deficiency condition worldwide and is also the most common deficiency condition following weight loss surgery. Especially, after gastric bypass surgery, the uptake of iron is not as efficient as before, and therefore the risk of iron deficiency is present. 


Iron deficiency is seen less frequently after a gastric sleeve operation but if you eat unilaterally and/or eat very little meat and cereal products, you are also at risk of iron deficiency. As with gastric bypass, iron deficiency occurs much more frequently in women of childbearing age.  

After a gastric bypass and mini bypass, the absorption of lime is reduced, and therefore you need calcium supplements for life, even if blood tests are fine. If you get too little calcium via the diet, the bones are descaled to maintain a normal calcium level in the blood. Blood samples that show normal calcium values, therefore, do not mean that you get enough calcium.


Vitamin D is also reduced for life after a gastric bypass surgery. If you get too little vitamin D, it reduces the amount of calcium in the intestine. Vitamin D and calcium deficiency can eventually lead to bone loss. Vitamin D deficiency can also cause muscle pain, fatigue and an increased risk of depression. 

After a gastric sleeve, you absorb lime and vitamin D as before the operation. If you eat and drink less than ½ liter dairy product a day, it is recommended to take calcium supplement together with vitamin D.


Anyone who has had a gastric bypass, mini bypass or sleeve surgery is recommended B12 supplement in the form of tablets or alternatively, as injection every 3 months and in some cases more frequently. 

Physical Exercise After Surgery

You may walk or cycle right after the operation. More intense exercise can be started after about 4 weeks. For the first 4 to 6 weeks, pay attention to not triggering pain from the surgery wound. Swimming is allowed after approx. 4 weeks when the wounds on the skin are healed. Exercise of abdominal muscles should also be postponed to approx. 4 weeks after surgery. 

Changing your exercise habits is important in order to achieve the required weight loss and is also crucial for you to maintain your weight loss in the long run. It is a good idea to study the possibilities for exercise in your area before the operation. Set short-term realistic goals e.g. ½ hour a day and then gradually increase. Strolling, cycling and swimming are good to start with as many muscle groups are involved without overloading knee and hip joints. The most important thing is, however, that you get started with a form of exercise that you think is fun and exciting. You must make sure to find a good rhythm in your daily life so that you exercise regularly. 

Later, strength training is relevant, as you must ensure that all muscle groups are trained. The advantage of strength training is that it tightens up and builds muscle while it burns calories during and after training. In addition to the planned exercise, you should also consider the possibilities for increased physical activity in your daily life. For example, short trips by car can be made on foot or by bike. Take the stairs instead of the elevator. Even small changes can produce great results. When you reach your goals, remember to reward yourself with anything but food. For example, it could be a good book, new clothes, massage etc.

You are allowed to have sex immediately after surgery. Please note that birth control pills are not a safe contraception after surgery as they are not absorbed to the required degree. Many therefore choose hormone spirals. We advise you to discuss this with your doctor. It is normal that bleeding disorders may occur after surgery.

The first 2 weeks, you are allowed to lift 5 kg in each hand. After two weeks you can gradually increase to your normal level within 4 weeks. However, you must avoid very heavy lifting during the first 6 weeks.


Your BMI indicates whether you qualify for weight loss surgery according to the international guidelines.






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