- Bariatric surgery is not a guarantee of successful weight loss and maintenance.
- Common operations include various banding procedures, which restrict the amount of food entering the stomach, the Roux-en-Y gastric bypass (RYGB), the duodenal switch (DS)/gastric sleeve (GS), or the biliopancreatic diversion (BPD) (Figure 1).
- The use of routine algorithms in postoperative care is essential to reduce the risk of weight regain (WR) and postoperative complications.
- Active nutritional patient education and clinical management to prevent and detect nutritional deficiencies are recommended for all patients undergoing bariatric surgery.
- Management of potential nutritional deficiencies is particularly important for patients undergoing malabsorptive procedures.
- All patients should participate in a comprehensive nutrition and lifestyle management program from a multidisciplinary team including an experienced primary care physician, endocrinologist, or gastroenterologist.
Assessment and Management
Postoperative Nutritional Management
- The Endocrine Society (ES) recommends that nutritional management should include an average of 60-120 g of protein daily for all patients to maintain lean body mass during weight loss and for the long term. This is especially important in those treated with malabsorptive procedures to prevent protein malnutrition and its effects (1|⊕⊕⊕◯).
- The ES recommends that long-term vitamin and mineral supplementation be considered in all patients undergoing bariatric surgery, with those who have had malabsorptive procedures requiring potentially more extensive replacement therapy to prevent nutritional deficiencies (1|⊕⊕⊕◯).
- The ES recommends periodic clinical and biochemical monitoring (Table 1) for micro- and macronutritional deficiencies after bariatric surgery (1|⊕⊕⊕◯).
Management of Diabetes Mellitus and Lipids
- The ES recommends that postoperative glycemic control should consist of achieving glycated hemoglobin (HbA1c) of 7% or less, with fasting blood glucose no greater than 110 mg/dL and postprandial glucose no greater than 180 mg/dL (1|⊕⊕⊕◯).
- The ES suggests that physicians and floor nurses be familiar with glycemic targets and insulin protocols, as well as the use of dextrose-free IV fluids and low-sugar liquid supplements (2|⊕◯◯◯).
- The ES recommends that obese patients with type 1 diabetes receive scheduled insulin therapy during their hospital stay, as required (1|⊕⊕⊕◯).
- The ES recommends that lipid abnormalities should be treated according to the current Adult Treatment Panel from the National Cholesterol Education Program (NCEP) guidelines and that existing lipid-lowering therapy for low-density lipoprotein (LDL) cholesterol and triglyceride values should be continued after surgery if levels remain above desired goals (1|⊕⊕⊕◯).
Bone Health and Gout
- The ES recommends that patients who have undergone malabsorptive surgical procedures (ie, RYGB, GS, BPD) should have vitamin D, calcium, phosphorus, parathyroid hormone (PTH), and alkaline phosphatase levels followed every 6 months and have a dual-energy x-ray absorptiometry for bone density performed yearly until stable (1|⊕⊕⊕◯).
- The ES recommends vitamin D and calcium supplementation postoperatively for malabsorptive obesity surgical procedures and that the doses are adjusted by a qualified medical professional based on serum markers and measures of bone density (1|⊕⊕⊕◯).
- The ES suggests that patients with frequent attacks of gout should have prophylactic therapy to lessen the chance of acute gout postoperatively as they lose weight (2|⊕◯◯◯).
Gastroenterological and Eating Behavior Considerations
- The ES recommends that bariatric surgery patients should sip fluids in the immediate postoperative period when fully awake after surgery and that they be discharged only if satisfactorily tolerating oral fluids (1|⊕⊕⊕◯).
- Particularly after procedures with a gastric restrictive component, the ES recommends that gradual progression of food consistency over weeks to months be used to allow patients to adjust to a restrictive meal plan and to minimize vomiting, which can damage surgical anastomoses or lead to gastroesophageal reflux after restrictive procedures (1|⊕⊕⊕◯).
- The ES suggests continuous reinforcement of new nutritional habits that discourage the intake of simple carbohydrate-dense foods and beverages, to minimize the frequency of bothersome gastrointestinal (GI) symptoms due to dumping, including abdominal pain and cramping, nausea, diarrhea, light-headedness, flushing, tachycardia, and syncope (2|⊕◯◯◯).
- The ES suggests that patients who present with postprandial symptoms of hypoglycemia, particularly neuroglycopenic symptoms, should undergo further evaluation for the possibility of insulin-mediated hypoglycemia (2|⊕◯◯◯).
Table 1. Schedule for Clinical and Biochemical Monitoring
|1 mo||3 mos||6 mos||12 mos||18 mos||24 mos||Annually|
|Complete blood count||X||X||X||X||X||X||X||X|
|Bone mineral density and body|
Table 2. Diagnosis and Treatment of Nutritional Deficiencies
|Deficiency||Symptoms and Signs||Confirmation||Treatment First Phase||Treatment Second Phase|
|Protein malnutrition||Weakness, decreased muscle mass, brittle hair, generalized edema||Serum albumin and prealbumin levels, serum creatinine||Protein supplements||Enteral or parenteral nutrition; reversal of surgical procedure|
|Calcium/vitamin D||Hypocalcemia, tetany, tingling, cramping, metabolic bone disease||Total and ionized calcium levels, intact PTH, 25-D, urinary N-telopeptide, bone densitometry||Calcium citrate, 1200-2000 mg; oral vitamin D, 50,000 units/d||Calcitriol|
oral vitamin D
|Vitamin B12||Pernicious anemia, tingling in fingers and toes, depression, dementia||Blood cell count, vitamin B12 levels||Oral crystalline B12, 350 mcg/d||1000-2000 mcg every 2-3 months IM|
|Folic acid||Macrocytic anemia, palpitations, fatigue, neural tube defects||Cell blood count, folic acid levels, homocysteine||Oral folate, 400 mg/d (included in multivitamin)||Oral folate,|
|Iron||Decreased work ability, palpitations, fatigue, koilonychia, pica, brittle hair, anemia||Blood cell count, serum iron, iron binding capacity, ferritin||Ferrous sulfate 300 mg bid-tid, taken with vitamin C||Parenteral iron administration|
|Vitamin A||Xerophthalmia, loss of nocturnal vision, decreased immunity||Vitamin A levels||Oral vitamin A, 5000-10,000 units/d||Oral vitamin A, 50,000 units/d|
Prevention and Treatment of WR
- Actionable WR is defined as over 50% of weight lost.
- A lesser degree of WR is not uncommon in patients undergoing bariatric surgery; it can be expected that 20%-25% of the lost weight will be regained over a period of 10 years.
- The ES recommends that a technically proficient surgical team, preferably accredited by a national certifying organization, and an integrated medical support team able to provide dietary instruction and behavior modification be available postoperatively and during long-term follow-up (1|⊕⊕⊕◯).
- The ES recommends that treatment of WR postoperatively should include a multidisciplinary approach to medical weight loss, including diet instruction, increased activity, behavior modification, and pharmacological therapy (1|⊕⊕⊕◯).
- The ES suggests, in cases of severe or unremitting postoperative weight gain, that the anatomic integrity of the surgical manipulation of the GI tract be evaluated (eg, absence of gastrogastric fistula after RYGB, integrity of band after a restrictive procedure). If not intact, a multidisciplinary team should consider all options, including patient education, behavior modification, additional weight loss therapies, or referral for revisionary surgery as clinically indicated (2|⊕◯◯◯).
Table 3. Causes and Prevention of WR
|Noncompliance with dietary and lifestyle recommendations|
|Physiological factors (variations in response to surgery)|
|Optimizing patient selection criteria|
|Realistic preoperative expectations|
|Consideration of benefits of bypass vs. restrictive procedures|
|Adherence to scheduled visits|