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Recommendations for bariatric patients to avoid complications during religious fasting

An international team of researchers has made several recommendation for patients with obesity who are may have or have undergone metabolic and bariatric surgery (MBS) but who wish to maintain common religious practices such as fasting. The authors state that there may be risks with fasting in patients with a history of MBS however, there is little published evidence on the possible complications during fasting and needs stronger recommendations and guidance to minimise them.


“For some patients, being unable to fast may make MBS untenable as an option and they need open counselling and advice. Patients should be advised about the risks of abdominal pain, dehydration, and marginal/peptic ulcer disease exacerbation while fasting, and review medications with their care team to garner advice about when and how to take medications,” they cautioned. “Work should be continued to identify how fasting can be done safely in the patient population, and in the meantime, patients should stay in close contact with their weight management team during periods of religious fasting.”


As a result of their findings, they authors made ten recommendations:

  • Prior to commencing religious fasting, it is advisable for patients to engage in consultations with their surgeons and multidisciplinary teams (MDT).

  • The regular utilization of proton pump inhibitors (PPIs) may be contemplated as a preventive and therapeutic measure for marginal ulceration (MU) during fasting.

  • After MBS, it is essential to provide patients with postoperative dietary recommendations and promote mindful eating habits before fasting. This serves as a reminder for patients to avoid rapid consumption and encourages thorough chewing when breaking their fasts.

  • To prevent the formation of kidney stones following MBS, it is recommended to maintain adequate hydration by consuming up to 2 L of water.

  • Collaborate with patients to develop strategies for effective hydration, including determining the appropriate timing and quantity of fluid intake before initiating the fast and after breaking it in the evening.

  • Patients necessitate re-education regarding smoking cessation, particularly as many individuals who experienced complications after MBS were actively smoking.

  • Diabetic patients who are on insulin therapy should be advised to consult their endocrinologists before embarking on fasting if they have undergone MBS.

  • Diabetic patients should engage in self-monitoring of their blood glucose levels and discontinue fasting if their readings exceed 300 mg/dl.

  • Patients with a history of diabetic ketoacidosis (DKA) within the three months preceding the Ramadan period may be classified as high-risk individuals, and it may be advisable for them to abstain from fasting.

  • Diabetic patients with a history of MB are also encouraged to refrain from consuming sweets and high-sugar foods during Iftar in order to prevent the DKA.

For this study, they conducted an international survey to well-known bariatric surgeons with experience offering MBS to Muslim patients. This is believed to be the first survey to look at complications following MBS when patients resume fasting in Ramadan which involves more than ten hours of fasting on average from food and water.


Surgeons were asked about the types of complications occurring during religious fasting in patients with history of MBS to evaluate the risk factors to manage and prepare more evidence-based recommendations. In total, 21 centres from 11 countries participated in this survey and reported a total of 132 patients with complications occurring during religious fasting after MBS.


Well-known bariatric surgeons with experience offering MBS to Muslim patients were invited to participate in the survey. The data were collected from April 2022 to July 2022 and reported information about age, gender, BMI at fasting, medications, comorbidities, and type of MBS (SG-LDJB: Sleeve Gastrectomy with Loop Duodeno-Jejunal Bypass; SG: Sleeve Gastrectomy; SADI-S: Single Anastomosis Duodeno-Ileal Bypass with Sleeve gastrectomy; SASI: Single-Anastomosis Sleeve Ileal Bypass; SASJ: Single-Anastomosis Sleeve Jejunal Bypass; BPD-DS: Biliopancreatic Diversion with Duodenal Switch; OAGB: One Anastomosis Gastric Bypass; RYGB: Roux-en-Y Gastric Bypass), complications (abdominal pain/ Epigastric pain/dyspepsia, nausea/vomiting, dehydration needs IV fluid, syncope, dumping, GERD, marginal ulcer, kidney stone, GI Bleeding, perforated marginal or peptic ulcer, acute cholecystitis and obstruction) and their management (surgery, EGD, PPIs, avoid fasting, conservative, IV fluid, Tranexamic acid).


Regarding the type of MBS in patients with complications during fasting, SG (n=46), OAGB (n=45), RYGB (n=19), SASI (n=9), SG-LDJB (n=8), BPD-DS (n=2), SASJ (n=1), SADI (n=1) and gastric plication (n=1) (Figure 1).


Figure 1: Types of surgery. SG-LDJB sleeve gastrectomy with loop duodeno-jejunal bypass, SG sleeve gastrectomy, SADI-S single anastomosis duodeno-ileal bypass with sleeve gastrectomy, SASI single-anastomosis sleeve ileal bypass, SASJ single-anastomosis sleeve jejunal bypass, BPD-DS biliopancreatic diversion with duodenal switch, OAGB one anastomosis gastric bypass, RYGB Roux-en-Y gastric bypass.

Of the 132 patients with complications after MBS who had admission to the surgical department or emergency department, 83.33% were females, mean age was 36.65±3.48 years and mean BMI was 43.12±6.86kg/m2 at the time the complications occurring during fasting. Mean onset of first time to fast after MBS was 6.22 months and the mean timing of complication occurring during fasting after MBS was 14.18 months. On average, the fasting period per day was 12.70 h (time between Suhoor and Iftar). Of the patients with complications 11.3% were smokers (14/132).


The most common complications were upper GI (gastrointestinal) symptoms including [gastroesophageal reflux disease (GERD), abdominal pain, and dyspepsia], marginal ulcers and dumping syndrome in 24% (32/132), 8.3% (11/132) and 23% (31/132) patients respectively. Surgical management was necessary in 4.5% of patients presenting with complications (6/132) patients due to perforated marginal or peptic ulcer in SADI-S, OAGB and SG, obstruction at Jejunojenostomy after RYGB (1/6) and acute cholecystitis (1/6).


Obesity related medical problems for patients at the time of complications were reported included hypertension (HTN) 21% (28/132), type 2 diabetes mellitus (T2DM) 18.9% (25/132), dyslipidaemia (DLP) 24.2% (32/132), GERD in 12.9% (17/132) patients, obstructive sleep apnea (OSA) in 6% (8/132) patients, and ischemic heart disease in one patient (0.8%). Most of patients were taking PPIs/H2blockers in 35% (41/132). Anti-hypertensive agents in 15% (18/132), lipid lowering agent in 10% (12/132), Levothyroxine in 8% (9/132), Allopurinol in 2% (3/132), NSAIDS in 2% (2/132), oral anti-diabetic/insulin in 12% (14/132), anticoagulant in 2% (2/132), antidepressant in 2% (3/132) and other medications (anti-hyperuricemic, urine alkalinizer, anti-migraine agent, corticosteroids, benzodiazepine) in 12% (14/132) were reported.


Esophagogastroduodenoscopy (EGD) was performed in 24% of patients with complications during fasting (32/132) with upper GI symptoms [gastroesophageal reflux disease (GERD), abdominal pain, and dyspepsia] and marginal ulcers in 8.3% of patients (11/132) most 8/11 after one anastomosis gastric bypass (OAGB) and 3/11 after (Roux-en-Y gastric bypass) RYGB]. Additionally, dumping syndrome occurred in 23.4% of patients (31/132), dehydration necessitating IV fluid in 18% of patients (24/132), nausea/vomiting in 25% of patients (33/132), syncope and kidney stone in 4% of patients (6/132), abdominal pain/epigastric pain/dyspepsia in 27% of patients (36/132).


Regarding management of complications, most complications were managed utilising conservative and supportive approaches including medical management in 36% of patients (48/132), dietary/lifestyle modification in 35.6% (47/132), rehydration (IV fluid) in 10.6% (14/132), avoiding fasting in 9% (12/132) and surgical management in 4.5% of patients [6/132] (4/6 patients due to perforated marginal ulcer after SADI-S and OAGB or perforated peptic ulcer after SG, 1/6 patients due to food bolus and obstruction at jejuno-jejunal anastomosis about three months after RYGB and laparoscopic cholecystectomy in 1/6 patients due to acute cholecystitis).


The findings were reported in the paper, ‘International survey on complications of religious fasting after metabolic and bariatric surgery’, published in the journal Scientific Reports.


To access this paper, please click here

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