Elsevier

Surgery for Obesity and Related Diseases

Volume 11, Issue 1, January–February 2015, Pages 230-237
Surgery for Obesity and Related Diseases

Original article
Effects of a very low calorie diet in the preoperative stage of bariatric surgery: a randomized trial

https://doi.org/10.1016/j.soard.2014.06.007Get rights and content

Abstract

Background

Preoperative bariatric patients can follow very low calorie diets (VLCD), reducing surgical risks. However, possible advantages of a liquid diet over one of normal consistency are controversial. This study investigated the effect of a liquid VLCD compared with one of normal consistency considering visceral fat (VF) loss and metabolic profile in preoperative clinically severe obese patients.

Methods

This was a randomized, open-labeled, controlled clinical trial. Patients were divided into 2 groups: liquid diet and normal diet. Data were collected at baseline and 7 and 14 days after intervention. Information gathered was analyzed for loss of weight and VF, biochemical data, anthropometric data, and energy intake.

Results

Fifty-seven patients consumed the liquid diet and 47 consumed the normal consistency diet. The liquid diet group lost significantly more weight (P<.0290) and VF (P<.0410) than the normal diet group. An inverse correlation occurred between VF loss and surgical time among the liquid diet group (r2 = -.1302, P = .001). Additionally, there was a positive correlation between the percentage of excess weight loss and ketonuria (P = .0070). No between-group difference occurred regarding calorie intake.

Conclusion

Patients that consumed a liquid diet presented a positive effect on reducing VF and greater weight loss than the normal diet group. Both VLCDs presented benefits offering a protective effect during the preoperative stage.

Section snippets

Methods

This clinical study was a randomized, open-label trial that was performed with patients who were preparing for a RYGB bariatric surgical procedure. This study was approved by the Ethics Committee of the Faculty of Health Services at the University of Brasilia (no. 160/09) and registered in Clinical Trials (NCT01748682). All participants signed an informed consent form.

The intervention period lasted 14 days. Fifteen days before surgery, patients were randomly selected to follow a liquid diet

Results

Of the 240 participants who were invited, 142 accepted the invitation to participate in the study and were randomly divided into 2 groups of 71 patients each. Of these 142 patients, 21 did not perform one of the US abdominal tests (13 patients of the ND group and 8 of the LD group), and 13 did not undergo blood tests (4 from the LD group and 9 from the ND group) at one of the evaluation moments and, thus, were excluded from the study population. Four other patients withdrew from participating

Discussion

The present study showed that both diets were effective in reducing weight in clinically severe obese patients in the preop stage of bariatric surgery. Volunteers from both groups lost weight, however, LD group performed better than the ND diet. Besides, patients who received LD presented a decrease in visceral fat and decreased surgical time.

The study by Riess et al. [6] found no association between preop weight loss and the duration of surgery or hospital stay. In their study, only some

Conclusion

The use of a VLCD in the preoperative period of bariatric surgery is safe and effective. The patients who followed the LD had greater overall fat loss and a notable decrease in visceral fat, along with a consequent reduction in the duration of surgery time. The use of LD has presented greater overall weight loss and a more rapid decrease in blood glucose compared with the ND.

The VLCD seems to be an important tool for the improvement of biochemical parameters among patients with clinically

Disclosures

The authors have no commercial associations that might be a conflict of interest in relation to this article.

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    Supported by Gastrocirurgica Clinic, Brasilia, Brazil, the University of Brasilia, Sabin laboratory and Essential Pharmacy Compounding Laboratory.

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