Data indicate a high prevalence of micronutrient deficiencies in morbidly obese subjects. Based on these results, we strongly recommend a systematic assessment of the micronutrient status in all candidates for bariatric surgery.

We performed a randomized clinical trial assessing the effectiveness and safety of laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (LRYGB). A total of 107 patients underwent LSG and 110 patients underwent LRYGB. The operative time was less for LSG than for LRYGB (87 ± 52.3 minutes vs 108 ± 42.3 minutes; P = 0.003). We observed a trend toward more early complications in LRYGB than in LSG (17.2% vs 8.4%; P = 0.067). Excessive body mass index loss 1 year after the operation was similar (72.3% ± 22% for LSG and 76.6% ± 21% for LRYGB). The comorbidities and quality of life were significantly improved by both procedures.

In comparison with nonobese control subjects, severely obese patients display a marked increase in hedonic hunger that is not observed in patients who have undergone gastric bypass surgery, suggesting that the operation normalizes excessive appetite for palatable foods, which may be an important pathophysiologic feature of severe obesity.

Data show a marked reduction of the hedonic drive to consume palatable food and beneficial changes in dietary habits characterized by an increased intake of protein-rich foods and vegetables and a reduced consumption of sugar-containing snacks and beverages after RYGB surgery. Based on these findings, it can be speculated that the reduction of the hedonic drive to consume palatable foods induced by RYGB surgery helps severely obese patients to establish healthier dietary habits.

Our data indicate that bariatric surgery, irrespective of the specific kind of procedure used, reverses most of the metabolic alterations associated with obesity and suggest profound changes in gut microbiome-host interactions after the surgery. This trial was registered at clinicaltrials.gov as NCT02480322.

Data provide evidence for an altered brain activity pattern in severely OB women and suggest that RYGB surgery and/or the surgically induced weight loss reverses the obesity-associated alterations.

Collectively, data clearly point to distinct changes in dietary habits after bariatric operations which markedly differ between gastric bypass and gastric banding patients. Overall, it is tempting to conclude that gastric bypass operations lead to a healthier and a more balanced diet than gastric band implantations.

While LRYGB has become a cornerstone in the surgical treatment of morbidly obese patients, concomitant cholecystectomy during LRYGB remains a matter of debate. The aim of this meta-analysis was to estimate the rate and morbidity of subsequent cholecystectomy after laparoscopic Roux-en-Y gastric bypass (LRYGB) in obese patients. A meta-analysis was performed analyzing the rate and morbidity of subsequent cholecystectomy in patients who underwent LRYGB without concomitant cholecystectomy. Thirteen studies met the inclusion criteria. The rate of subsequent cholecystectomy was 6.8 % (95 % CI, 5.0-8.7 %) based on 6,048 obese patients who underwent LRYGB without concomitant cholecystectomy. The rate of subsequent cholecystectomy due to biliary colic or gallbladder dyskinesia was 5.3 %; due to cholecystitis, 1.0 %; choledocholithiasis, 0.2 %; and biliary pancreatitis, 0.2 %. The mortality after subsequent cholecystectomy was 0 % (95 % CI, 0-0.1 %). The surgery-related complication rate after subsequent cholecystectomy was 1.8 % (95 % CI, 0.7-3.4 %) resulting in a risk of 0.1 % (95 % CI, 0.03-0.3 %) to suffer from a cholecystectomy-related complication in patients undergoing LRYGB without concomitant cholecystectomy. A prophylactic concomitant cholecystectomy during LRYGB should be avoided in patients without cholelithiasis and exclusively be performed in patients with symptomatic biliary disease.