Efficacy of Liquid Versus Powder Protein Supplementation to Optimize Protein Intake After Bariatric Surgery


Hospital Clinic of Barcelona




Weight Loss
Bariatric Surgery Candidate
Protein Supplementation
Body Composition


Dietary Supplement: High protein liquid formula

Study type


Funder types




Details and patient eligibility


The goal of this randomized control trial is to compare the effect of a liquid formula rich in nutrients and low in calories (supplement) with the progressive diet with conventional foods that we usually recommend in patients after surgery. The main question it aims to answer is if the addition of a high-protein, volume-controlled nutritional supplement as a fundamental part of the diet during the first two months after surgery will preserve the patient's nutritional status and prevent the appearance of nutritional deficits and associated complications. Participants will be evaluated at the beginning, at 1 month and at the end of the study (2m) and the following determinations will be made: Analytical determination Nitrogen balance by determining urea N2 in 24-hour urine Anthropometric determinations Body composition determined by impedanciometry Resting energy expenditure and nutrient oxidation measured by indirect calorimetry. Energy, protein and hydration intake. Gastrointestinal tolerance through self-registration of symptoms. Researchers will compare the effect of a complete hypocaloric liquid formula group with the usual progressive diet group to see if they achieve the protein intake goal established for patients after obesity surgery, preservation of nutritional status and lean mass during the rapid phase of weight loss and the gastrointestinal tolerance during the first two months after surgery.


50 patients




18 to 65 years old


No Healthy Volunteers

Inclusion criteria

Patients of both sexes between 18 and 65 years of age undergoing bariatric surgery in our center With the ability to understand the objectives and proposals of the study That they agree to participate in the study.

Exclusion criteria

Patients who have had perioperative complications and who require an extended hospital stay Patients who after the intervention require some type of artificial nutritional support Patients who have undergone a surgical technique other than BPG.

Trial design

Primary purpose




Interventional model

Parallel Assignment


None (Open label)

50 participants in 2 patient groups

High protein liquid formula
Experimental group
Patients allocated in the intervention group (n=15) received 4 high-protein shakes and the corresponding standard vitamin-mineral (VM) supplementation according to our post BS protocol, then progressed towards a diet that combines traditional foods with 2 hLF shakes per day and VM supplementation for 15 days. Over the following 15 days, patients continued to normalize their diet, including a single hLF shake per day and continued with VM supplementation.
Dietary Supplement: High protein liquid formula
Standard care diet
No Intervention group
Patients in the control group (n=35) followed the traditional protocol after bariatric surgery (sCD-group) consisting of a progressive diet with traditional foods, recommendation of 23g/d of protein powder and standard vitamin-mineral supplementation during the first 2 weeks after the surgery. From then on and according to current dietary protocols, the recommendation for protein powder decreases from 23g to 15g up to the end of the study.

Trial contacts and locations



Data sourced from clinicaltrials.gov

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