Candidates to bariatric surgery at The Bariatric and Metabolic Institute at Cleveland Clinic Florida are prescribed a high protein liquid diet for two weeks preoperatively and 2 weeks postoperatively. Whether Wolffia Globosa (Mankai), a plant based wholesome food, can serve as a natural alternative to liquid diet during the 2 week pre-operation and 2 weeks postoperation liquid based diet, is unknown.

The investigators aim to address the effect of daily Wolffia Globosa (Mankai) administration on morbid/severely-obese patients during the 2 week pre-operative period and 2 weeks postoperatively as compared to iso protein-iso caloric shake source on the following parameters

This study is a prospective study involving patients selected for elective surgery. Patients undergoing bariatric surgery will be enrolled in this study and have several parameters checked as explained below. Patients selected and consented for elective bariatric surgery will be recruited in the Bariatric and Metabolic Institute to participate in this study and will undergo standard of care. The investigators will enroll approximately 120 candidates during a 6 months (~5 a week) period. Patients will be randomized to the A. control group: 3 traditional shakes or B. intervention group: 2 traditional shakes and 1 daily administration of substituting iso-protein green Wolffia Globosa (Mankai) Shake (4 frozen cubes of Wolffia Globosa (Mankai) equal to 20 grams of dry Wolffia Globosa (Mankai). Each shake will provide equivalent carbohydrate, calories and protein levels from the respective source. As part of our routine pre and postoperative screening and follow up protocol, the investigators will collect anthropometric and clinical data on all patients, including standard of care blood samples collected at 2 weeks pre operatively, surgery day and at 2 months postoperatively

Inclusion Criteria:

• Patients that will undergo sleeve gastrectomy.

Exclusion Criteria:

• Age below 18 years
• American Society of Anesthesiologist (ASA) class IV or V
• Patients using Vitamin-K antagonists
• Patients with documented coagulopathies.

Confidentiality and Privacy:

Information about study subjects will be kept confidential and managed according to the Health Insurance Portability and Accountability Act of 1996 (HIPAA).

Source Documents:

Source data will include the electronic health record for patient demographics, vitals, and basic laboratory results. Dictated operative notes will be maintained within the EHR as well. Lab results of inflammatory markers will be kept out of the EHR and kept in a secure file on the Cleveland Clinic server.

Records Retention:

The investigators will retain study essential documents for at least six years after completion of the research and are accessible for inspection by authorized representatives at reasonable times and in a reasonable manner.