Can bariatric surgery make you smarter? Research suggests that weight loss surgery may improve certain aspects of brain function, including memory, attention, and concentration. However, there is currently no convincing evidence that bariatric surgery increases IQ or general intelligence. Source: 2024 Meta-Analysis | 2024 Clinical Trial
What Does the Research Show?
A 2024 meta-analysis published in Obesity Surgery examined 11 studies involving 728 patients. Researchers found significant improvements in memory, attention, and executive function—the mental skills involved in planning, decision-making, and problem-solving—following bariatric surgery.
Another 2024 study published in JAMA Network Open followed 133 adults undergoing bariatric surgery. After two years, 42.9% of participants with evaluable data demonstrated at least a 20% improvement in their overall cognitive test score.
However, these findings do not establish that surgery directly caused the improvements. A 2025 systematic review in Obesity Reviews comparing surgical patients with nonsurgical groups found very uncertain evidence of improved attention and little to no improvement in memory or executive function.
Does Bariatric Surgery Change the Brain?
Researchers have also investigated whether significant weight loss affects the brain’s physical structure.
A 2020 MRI study published in NeuroImage followed 29 patients undergoing gastric sleeve surgery. Researchers observed increased gray- and white-matter density in several brain regions following surgery, particularly after 12 months.
A separate 2024 brain imaging study identified changes in the temporal cortex, a brain region involved in memory and other cognitive processes.
While these findings suggest that brain structure can change after bariatric surgery, they do not prove that patients become more intelligent.
Does Weight Loss Surgery Increase IQ?
Improved cognitive performance is not the same as increased intelligence.
A 2024 randomized clinical trial published in eClinicalMedicine compared bariatric surgery with intensive nonsurgical treatment in 46 adolescents. After two years, researchers found no statistically significant difference in estimated IQ between the groups.
The study was relatively small and involved adolescents, but it reinforces why claims about increased intelligence should be approached cautiously.
The Importance of Long-Term Brain Health
Patients should also understand that nutritional care after bariatric surgery is essential. Vitamin B1 (thiamine) deficiency can cause serious neurological complications, making appropriate supplementation and postoperative monitoring important. The American Society for Metabolic and Bariatric Surgery’s 2025 clinical guidelines address the prevention and management of these complications.
The Bottom Line
Current research suggests bariatric surgery may be associated with improvements in certain cognitive abilities, particularly attention and memory. However, the evidence remains mixed, and surgery has not been proven to increase IQ.
For patients considering weight loss surgery, these possible cognitive benefits are an interesting area of emerging research—not a guaranteed outcome.
Learn more about gastric sleeve surgery in Mexico and gastric bypass surgery at Renew Bariatrics.
Scientific References
ASMBS Wernicke’s Task Force (2025). Clinical Guidelines on Prevention, Diagnosis, and Treatment of Wernicke’s Encephalopathy and Wernicke-Korsakoff Syndrome. PubMed
Tao et al. (2024). Bariatric Surgery Improves Cognition Function in the Patients with Obesity: A Meta-Analysis. Obesity Surgery. PubMed
Custers et al. (2024). Long-Term Brain Structure and Cognition Following Bariatric Surgery. JAMA Network Open. Full Study
van Reekum et al. (2025). Psychiatric and Cognitive Functioning After Metabolic and Bariatric Surgery: A Systematic Review and Meta-Analysis. Obesity Reviews. Full Study
Michaud et al. (2020). Neuroanatomical Changes in White and Grey Matter After Sleeve Gastrectomy. NeuroImage. PubMed
Järvholm et al. (2024). Cognitive Functioning in Adolescents with Severe Obesity Undergoing Bariatric Surgery or Intensive Non-Surgical Treatment. eClinicalMedicine. PubMed
