Post-Discharge Bariatric Information Leaflet for General Practitioners and Patients

Patient Experience

  • Reference Number: HEY1118/2023
  • Departments: Bariatric Surgery
  • Last Updated: 30 November 2023


Your patient has now been discharged from the Tier 4 Bariatric Surgery Pathway; the information provided in this leaflet is to assist General Practitioners in the ongoing management of patients following bariatric surgery.

For further, more in-depth information, please see guidelines from the Royal College of General Practitioners and British Obesity and Metabolic Surgery Society, links are available at the back of this leaflet.

Impact of surgery on nutrition

The main bariatric procedures undertaken at Hull University Teaching Hospital NHS Trust are Roux-En-Y Gastric Bypass and Sleeve Gastrectomy with the duodenal switch being less frequent. Initially after surgery patients start on a liquid diet, then progress to pureed food, to soft food and then to normal textured food. Patients should be able to manage a wide range of textures 2 years post-operatively.

It should not be assumed that all patients are eating a “well balanced” diet. Some patients may have maladaptive eating behaviours which can result in poor nutritional intake.

Surgical Procedure Impact on nutrition
Gastric Band No impact on nutrition

Overly tight gastric bands affect nutritional quality of diet including protein and iron

Sleeve Gastrectomy May be some impact on absorption including iron and vitamin B12
Gastric Bypass Impacts on absorption of iron, vitamin B12, calcium and vitamin D

Long limb bypasses may affect absorption of protein, fat, vitamin A and trace elements in addition

Duodenal Switch Impacts on absorption of protein, fat, calcium, fat soluble vitamins A, D, E and K, zinc

Table adapted from British Obesity & Metabolic Surgical Society GP Guidance: Management of nutrition following bariatric surgery 2014

Post-nutritional supplementation (routine)

Nutrition is compromised after bariatric surgery and it is recommended that the patient takes nutritional supplementation lifelong in addition to having a nutritionally balanced diet.   It is imperative that patients remain compliant in taking their supplements and this should be checked regularly.

Hull University Teaching Hospital NHS Trust’s policy recommends that your patient will require the following supplementary medications for life:

  • Vitamin D 2000 to 4000 international units (with the ideal vitamin D range being greater than 75 nanomoles per litre (nmol/L) (some patients will require calcium and vitamin D)
  • Multivitamins with minerals
  • Vitamin B12
  • Iron in selected patients only

Oral Cyanocobalamin 1mg once daily can be prescribed as an alternative to vitamin B12 injections

The Bariatric Service recommends annual vitamin B12 blood tests

Post-operative blood monitoring

Continued nutritional lifelong monitoring is essential following bariatric surgery to ensure patients do not develop nutritional problems. Abnormal blood results are not always related to surgery itself.

The Bariatric BOMSS Guidelines recommend that your patient should have the following blood tests (bariatric blood profile) annually around the time of the month of their operation.

Roux-en-Y Gastric Bypass Sleeve Gastectomy Duodenal Switch Gastric Band
Urea and electrolytes Yes Yes Yes Yes
LFTs Yes Yes Yes Yes
Bone profile Yes Yes Yes Yes
Full blood count Yes Yes Yes Yes
Ferritin Yes Yes Yes Yes
Folate Yes Yes Yes Yes
Vitamin B12 Yes Yes Yes No
Vitamin D Yes Yes Yes Yes
Vitamin E No No Yes No
Vitamin A No No Yes No
Vitamin K No No Yes No
Zinc Yes Yes Yes No
Copper Yes Yes Yes No
Selenium Yes Yes Yes No

Suggested additional blood tests to consider:

Thiamine If the patient presents with rapid weight loss, poor dietary intake, vomiting, alcohol abuse, oedema or symptoms of neuropathy, initiate treatment for thiamine deficiency immediately.  Do not delay pending blood results
HbA1c Monitor HbA1c in patients with pre-operative diabetes
Lipids Monitor lipids in patients with pre-operative dyslipidaemia
Selenium Chronic diarrhoea, metabolic bone disease, unexplained anaemia or unexpected cardiomyopathy
Zinc Unexplained anaemia, hair loss or changes in taste acuity, if taking copper supplements
Copper Unexplained anaemia or poor wound healing.  History of taking zinc supplements

Emergency department management of bariatric patients

BOMSS traffic light poster for the management of complications of post-bariatric surgery

Top 10 tips for General Practitioners

Please see below the ten top tips for the management of patients post bariatric surgery in primary care extracted from the Royal College of General Practitioners for further information please access the internet link provided in the appendices. 

Ten top tips for the management of patients post bariatric surgery in primary care

  1. Keep a register of bariatric surgery patients and record the type of procedure in the register. Please note that follow up varies according to the type of surgery.
  2. Encourage patients to check their own weight regularly and to attend an annual BMI and diet review with a health professional.
  3. Symptoms of continuous vomiting, dysphagia, intestinal obstruction (gastric bypass) or severe abdominal pain require emergency admission under the local surgical team.
  4. Continue to review co-morbidities post-surgery such as diabetes mellitus, hypertension, hypercholesterolaemia and sleep apnoea, as well as mental health.
  5. Review the patient’s regular medications. The formulations may need adjusting post-surgery to allow for changes in bio-availability post-surgery.
  6. Bariatric surgery patients require lifelong annual monitoring blood tests, including micronutrients. Encourage patients to attend for their annual blood tests.
  7. Be aware of potential nutritional deficiencies that may occur and their signs and symptoms. In particular, patients are at risk from anaemia and vitamin D deficiency, as well as protein malnutrition and other vitamin and micronutrient deficiencies. If a patient is deficient in one nutrient, then screen for other deficiencies too.
  8. Ensure the patient is taking the appropriate lifelong nutritional supplements required post-surgery as recommended by the bariatric centre. Ensure guidance regarding vitamin supplementation has been issued by the bariatric surgery team. Request a copy for the patient’s GP records if this has not been included in the discharge information.
  9. Discuss contraception – ideally pregnancy should be avoided for at least 12 to 18 months post-surgery.
  10. If a patient should plan or wish to become pregnant after bariatric surgery, alter their nutritional supplements to one suitable during pregnancy. Inform the local bariatric unit of patient’s pregnancy and the obstetric team of the patient’s history of bariatric surgery.”

Healthy eating long term after weight loss surgery

Healthy diet and lifestyle are key to long term weight loss success. Without continuing a balanced diet and being active weight regain can occur.

The following ideas should help you achieve weight loss and help you keep your weight stable long term.

  1. Eat 3 meals per day.

Missing meals can lead to you overeating later in the day. It can also increase the chances of snacking, grazing and making unhealthy food choices. Try to spread meals out evenly across the day to avoid the feeling of hunger or cravings.

Missing meals can also lead to low levels of vitamins, minerals and proteins in your body. This can impact on how well your body functions and cause ill health. Use a side plate to help keep portion sizes small.

  1. Make sure all meals are balanced

Include fruits or vegetables, proteins and starchy carbohydrates with each meal.

Protein rich foods include: meat, fish, eggs, beans, pulses and lentils, dairy and meat alternatives. These foods keep you full for a long time, help keep muscles strong and are important for growth and healing.

Starchy carbohydrates include: bread, rice, pasta, potatoes and cereals. Choose whole grain/brown options as able as these contain fibre which is important for bowel health and will keep you fuller for longer.

Fruits and vegetables can be fresh, tinned or frozen. You should include a wide range of different fruits and vegetables in your diet as these contain vitamins and minerals. They are also a good source of fibre to help you feel fuller for longer.

  1. Make sure you drink plenty of fluid

Aim for 2 to 3 litres of water a day. You can add no added sugar squash. Teas and coffees are also included but try to drink plenty of fluids that do not contain caffeine. Avoid fizzy drinks.

  1. Stop drinking 30 minutes before a meal and start drinking 1 hour after.
  1. Do not drink too much alcohol.

See the NHS choices website for more information regarding alcohol. Speak with you GP about alcohol if you feel you would like support with reducing how much you drink. Be aware alcohol contains lots of calories that can lead to weight re-gain.

If you would like more support with healthy eating, weight loss or making dietary changes, speak with your GP about referral to a community dietitian or local weight management services.

If your patient has any further complications, they can be re-referred back to the Hull University Teaching Hospital Trust’s Bariatric Service using the electronic referral system (eRS).


For further BOMSS Guidance please go to BOMSS – British Obesity and Metabolic Surgery Society or British Obesity and Metabolic Surgery Society Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery

Table 1: British Obesity & Metabolic Surgical Society, clinical resources, primary care resources Primary care management of post operative bariatric patients image – Flow chart of post-operative concerns after bariatric surgery

Extra 1: Royal College of General Practitioners – Ten top tips for the management of patients post bariatric surgery in primary care (September 2014)

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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