Obese patients, who underwent bariatric surgery, are at risk to develop protein malnutrition. The aim of this study is to evaluate the influence of postoperative protein supplementation on weight reduction, body composition and protein status.

Bariatric surgery has become a major treatment option for severe obesity in adults. It has proven its efficiency regarding weight loss and its benefits concerning the improvement or even remission of obesity related comorbidities. Additionally, bariatric surgery procedures can be performed laparoscopically, which decreases the complication rate and reduces postoperative pains. Despite the advantages of bariatric surgery, attention needs to be paid to the possible risks following the surgical treatment. Postoperative risks often concern the nutritional status. It has been shown that, beside different micronutrient deficiencies, bariatric surgery also leads to an increased risk of developing protein malnutrition. Discussed reasons for this are the malabsorption of nutrients and the restricted food intake after surgery, which may lead to reduced protein consumption. Postoperative occurrence of vomiting or different food intolerances may support this effect. Accordingly, if an inadequate supply persists, a protein deficit will occur and this, in turn, may lead to an undesirable reduction in muscle mass and plasma protein levels. Based on this background, numerous studies indicate an increased incidence of protein malnutrition after bariatric surgery by detecting a decrease in levels of albumin and prealbumin, a significant reduction in lean body mass, as well as an inadequate protein intake after surgical treatment.

Dietary proteins have shown to play an important role in body weight regulation. There is evidence that a protein-rich diet is supposed to facilitate weight loss, to support successful weight maintenance, to attain satiety and to preserve lean body mass. Therefore, the use of protein supplements after bariatric surgery may minimize the risk for developing protein malnutrition and hence optimize the postoperative care.

The primary aim of this randomized, placebo-controlled, double blind pilot study was to evaluate the influence of postoperative protein supplementation on body weight reduction, body composition and protein status.

Inclusion Criteria:

• Age between 18 and 65 years
• BMI of 35 kg/m2 or more
• Indication for laparoscopic sleeve gastrectomy or Roux-en Y gastric bypass

Exclusion Criteria:

• Renal disease
• Type 2 diabetes