Objective To summarize the changes of nutrition and metabolism after laparoscopic Roux-en-Y gastric bypass surgery (LRYGBP) in the treatment of morbid obesity. Methods LRYGBP was performed in 121 patients with morbid obesity (male, 40 patients; femal, 81 patients). The body mass index (BMI) was measured 1 month before and 6 months after the operation. A comparative analysis was conducted on serum levels of ferrum (Fe), calcium (Ca), zincum (Zn), selenium (Se), vitamin A (VitA), vitamin D (VitD), vitamin B_ 12 (VitB_ 12 ), and parathyroid hormone (PTH) at 6, 12, and 24 months after operation. Results The BMI was declined from 47.00?7.15 kg/m~2 preoperatively to 33.79?6.06 kg/m~2 postoperatively, with a decrease of 0.26~42.58 kg/m~2 (13.21?5.47 kg/m~2) (t=26.103, P=0.001). The postoperative serum levels of Fe, Ca, Zn, Se, VitA, VitD, and VitB_ 12 were all within the normal limits. However, the levels of Zn, Se, and VitA were lower than the normal in 19.5% (17/87), 22.7% (20/88), and 3.7% (28/83) of patients at 6 months after operation, and in 6.0% (2/30), 11.5% (3/26), and 17.2% (5/29) of patients at 2 years after operation, respectively. The serum PTH levels were 11~161 pg/ml (66?34 pg/ml), 24~154 pg/ml (72?34 pg/ml), and 21~194 pg/ml (75?40 pg/ml) at 6, 12, and 24 months after operation, respectively (normal limits, 9~44 pg/ml). Conclusions Laparoscopic Roux-en-Y gastric bypass surgery is a reliable and safe option for patients with morbid obesity. The serum levels of calcium, zinc, selenium, and PTH will be influenced following the surgery. Supplementation of multi-vitamins and mineral substances should be strongly advised in all patients.