Low Vitamin B12 became more common after weight-loss surgery, rising from 8.15% to 18.52% over 12 months. The study followed 135 people with obesity through their first year after surgery. Researchers measured Vitamin B12, Ferritin, and Folate before surgery and during follow-up. They also tracked how much Weight people lost. By 12 months, the middle result for total weight loss was 30.66%. Yet low nutrient levels became more common across all three tests. The share with low Ferritin rose from 6.67% to 27.61%. For Folate, it rose from 0.74% to 5.19%. The share with low Vitamin B12 more than doubled. That does not mean everyone's blood level fell by the same amount. The study's main finding about weight loss involved Ferritin, not Vitamin B12. Higher Ferritin at 12 months was linked to greater loss of excess weight. But larger drops in Ferritin were also linked to greater weight loss. These links do not show that raising Ferritin causes more weight loss. The summary did not report a clear link between Vitamin B12 and weight loss. For this community, the takeaway is that scale changes and nutrient levels tell different stories. Comparing bloodwork before surgery with later results can show changes the scale misses. Members sharing their numbers can include test dates and time since surgery. That makes comparisons more useful than a single result alone. What changes have you seen in your Vitamin B12 numbers after weight-loss surgery?