Commercial Very Low Energy Meal Replacements for Preoperative Weight Loss in Obese Patients: a Systematic Review.

BACKGROUND: This systematic review assessed feasibility and effectiveness of preoperative meal replacements to improve surgical outcomes for obese patients. METHODS: PRISMA guidelines were followed and electronic databases searched for articles between January 1990 and March 2015. RESULTS: Fifteen studies (942 participants including 351 controls) were included, 13 studies (n = 750) in bariatric patients. Adverse effects and dropout rates were minimal. Ten out of 14 studies achieved 5-10 % total weight loss. Six of six studies reporting liver volume achieved 10 % reduction. Endpoints for perioperative risks and outcomes were too varied to support definitive risk benefit. CONCLUSIONS: Commercial meal replacements are feasible, have minimal side effects and facilitate weight loss and liver shrinkage in free-living obese patients awaiting elective surgery. A reduction in surgical risk is unclear.

Does preoperative oral carbohydrate reduce hospital stay? A randomized trial.

Oral carbohydrate-rich fluids are used preoperatively to improve postoperative recovery, but their effectiveness for reducing length of hospital stay is uncertain. We assessed the effectiveness of preoperative loading with carbohydrates on the postoperative outcomes of 44 patients scheduled for elective colorectal surgery who were randomly allocated to a carbohydrate-rich fluid group or a usual care group during their preadmission clinic visit. Our primary outcome was the time patients required to be ready for discharge. Patients in the control group spent an average of 4.3 days (95% confidence interval [CI], 3.2-5.7) in the hospital and patients in the carbohydrate-rich fluid group spent 4.1 days (95% CI, 3.2-5.4) in the hospital until they met discharge criteria (P = .824). We found that the safety of administering preoperative oral carbohydrate-rich fluids is supported, but we were unable to confirm or refute the benefit of this treatment regimen for contributing to shorter hospital stays after elective colorectal surgery.