The risks and trade-offs no one should skip over—and how to manage them

The risks and trade-offs no one should skip over—and how to manage them

Bariatric surgery is safe in experienced hands, but it does change how you absorb nutrients and alcohol, and it affects bone health. Knowing the risks—and the fixes—is part of informed consent.

Nutritional gaps (lifelong)

Common deficiencies after SG and RYGB include vitamin B12, iron, folate, thiamine, vitamin D and calcium. That’s why a daily multivitamin plus targeted supplements (often B12, iron, calcium, vitamin D) and at least yearly bloods are standard. Teams typically recommend lifelong supplementation. PMCASMBS+1

Practical tip: Use bariatric-specific multivitamins or check that your off-the-shelf multivitamin meets the guideline doses; your clinic will tailor extras based on your labs. NCBI

Bone health

Bone turnover rises after rapid weight loss, and fracture risk is higher—particularly after RYGB—so routine vitamin D/calcium, weight-bearing exercise, and targeted therapy for high-risk patients matter. Recent work shows bone loss can begin within months and fracture risk rises over years; RYGB tends to have a greater skeletal impact than SG. Naturejamanetwork.comOxford Academic

Alcohol and mental health

After RYGB in particular, alcohol is absorbed faster and peak levels are higher; rates of alcohol use disorder appear to increase in some patients. If you’ve had problematic alcohol use in the past, discuss this carefully with your team and consider stricter limits or abstinence. PMC

Gallstones during rapid weight loss

Rapid weight loss is lithogenic (gallstone-forming). Several trials and meta-analyses show ursodeoxycholic acid (UDCA) can lower gallstone formation after surgery, although not every study finds fewer symptomatic events in all groups. Many programmes consider UDCA (often ~500–600 mg/day for 6 months) when the gallbladder is in situ. SoardPubMedPMCthelancet.com

Pregnancy

Nutritional monitoring is stricter if you fall pregnant after surgery. Most teams advise delaying conception 12–18 months and individualising supplements and growth monitoring. PMC+1

The bottom line on safety

Serious complications are uncommon in accredited centres, but lifelong follow-up is non-negotiable: scheduled labs, supplements, and early attention to symptoms (vomiting, severe reflux, weakness, hair loss, neuropathy) keep you well for the long haul. ASMBS

References

• de Sousa JPV et al. Assessing nutritional deficiencies after bariatric surgery (2024). PMC
• AACE/TOS/ASMBS/OMA/ASA Clinical Practice Guidelines—peri-operative and long-term care (2020). ASMBS
• ASMBS: Life after bariatric surgery—supplements for life. ASMBS
• Farup PG et al. Early changes in bone markers after surgery (2024). Nature
• Elaine WY et al. Fracture risk after RYGB vs banding (2019). jamanetwork.com
• Cailleaux PE et al. Long-term differential skeletal and metabolic effects of RYGB vs SG (2024). Oxford Academic
• Grover R et al. Alcohol risks after bariatric surgery (2024). PMC
• Fearon NM et al. Meta-analysis: UDCA lowers gallstones after bariatric surgery (2022). Soard
• Sugerman HJ et al. RCT: UDCA 600 mg/day prevents gallstones after bypass (1995). PubMed
• Miller K et al. RCT: UDCA 500 mg/day after gastric restrictive procedures (2003). PMC
• Haal S et al. RCT: UDCA and symptomatic gallstones after bariatric surgery—mixed findings (2021). thelancet.com
• Shawe J et al. Consensus guidance on pregnancy after bariatric surgery (2019); Burlina S et al. Nutrition in pregnancy post-surgery (2023). PMC+1