Bariatric surgery (CB) is the most successful method for weight loss in patients with Grade III obesity and morbidities. However, patients submitted to CB generally do not reach the protein intake recommendation. Thus, protein supplements could minimize muscle mass loss, preventing protein malnutrition. Whey protein has a high biological value, with a high content of branched-chain amino acids that stimulate protein synthesis and reduce the loss of muscle mass seen in low-calorie diets. Thus, whey protein would contribute to maintaining body composition and preventing muscle loss. Our objective was to evaluate the effect of 8-week whey protein supplementation in female patients submitted to CB, regarding metabolic and nutritional status. After the eight weeks of the experiment, there was an increase in lean Mass and a reduction of fat Mass and fat percentage in the Whey group compared with the initial time, a result not seen in the control group. There was no difference in biochemical parameters, except for the increased fasting glucose in the Malto group that was prevented in the Whey group. We conclude that whey protein supplementation could reduce the loss of fat-free Mass and increase the body fat Mass regardless of changes BMI evolution in the later postoperative period of bariatric surgery, a period of weight loss is minimized, and weight reacquisition occurs more frequently.

Introduction: Adequate protein intake is essential for maintaining lean body mass during weight loss, particularly for patients undergoing bariatric surgery (BS). Whey protein supplementation may help meet daily protein requirements. This study aimed to assess the effects of whey protein supplementation on weight loss and body composition in women during the medium-term postoperative phase following BS. Methods: In a double-blind, controlled study over four weeks, 24 women received 30 g of whey protein (Whey group), while 19 received 30 g of maltodextrin (Malto group). Body composition, energy expenditure, muscle thickness, muscle strength, walking performance, and dietary intake were evaluated. Results: Compared to the Malto group, the Whey group showed greater reductions in body weight (median: −0.6 kg vs. −0.2 kg, respectively) and fat mass (median: −1.1 kg vs. −0.25 kg, respectively), along with an increase in fat-free mass (−0.7 kg vs. 0.6 kg, respectively). Muscle thickness improved in the Whey compared to the Malto group in the abdominal (0.07 mm vs. −0.04 mm, respectively) and thigh (0.4 mm vs. −0.15 mm, respectively) regions. Additionally, muscle mass reduction was less pronounced in the Whey group (−3 kg vs. −0.13 kg). No significant differences were observed in handgrip strength, gait speed, or nutrient intake. Conclusions: Whey protein supplementation may be beneficial, as it enhances weight loss and preserves fat-free and muscle mass more effectively than a diet without this supplementation in women during the stabilization phase or late postoperative period of BS.

Gluten-free diets (GFDs) have gained popularity in the general population. Nonetheless, controlled studies are necessary before decisions can be made to promote GFDs. We aimed to evaluate the effec...