NUTritional Impact of a Hypocaloric Hyperprotein Diet Before Obesity Surgery

Obesity is a major public health problem and is constantly on the rise. Therapeutic approaches based on dietary advice, physical activity and the management of psychological difficulties are not always sufficient to achieve a lasting weight reduction. Bariatric surgery (or obesity surgery), accompanied by therapeutic education and adequate medical and dietary monitoring, can lead to significant and lasting weight loss. It is indicated as a second-line treatment for patients who have failed medical treatment, whose BMI is greater than or equal to 40 or whose BMI is greater than or equal to 35 with comorbidities (type 2 diabetes, arterial hypertension, obstructive sleep apnoea-hypopnoea syndrome, severe joint disorders). The surgeon may be very bothered by the intra-abdominal fat mass and especially by steatotic hepatomegaly (increase in the size of the liver and its fat load). Faced with this problem, various preoperative strategies such as the placement of an intra gastric balloon have been tried to decrease the size of the liver but a systematic review from 2016 indicates that a low calorie diet is preferable. Preoperative weight loss can reduce fat load and liver volume very rapidly. This meta-analysis shows that all low-calorie, high-protein diets are effective and that the optimal duration (4 weeks), compliance and tolerance are important factors for success. However, there is no consensus on the benefit/risk balance of a preoperative diet and there is considerable variability in approach at national and international level. The present clinical study involves a triad of dietician, surgeon, physician (endocrinologist/nutritionist or internist) to secure this diet. It could provide a database to help estimate the risk of undernutrition in the obese subject. This diet, designed to facilitate the surgical procedure and potentially reduce intraoperative complications, is inexpensive, easily accessible and reproducible by other teams. This innovative management could standardise the preoperative management of patients undergoing bariatric surgery at national level. It would also improve the results of bariatric surgery both in the short term by reducing complications and in the long term by increasing weight reduction as reported in the Livhits meta-analysis. The risk of undernutrition should be reduced by this hypocaloric hyperprotein diet and consequently cancel out the increased risk of mortality, infections, delayed healing, longer hospital stay and the costs that this would entail.