Diet approach before and after bariatric surgery

Abstract

Bariatric surgery (BS) is today the most effective therapy for inducing long-term weight loss and for reducing comorbidity burden and mortality in patients with severe obesity. On the other hand, BS may be associated to new clinical problems, complications and side effects, in particular in the nutritional domain. Therefore, the nutritional management of the bariatric patients requires specific nutritional skills. In this paper, a brief overview of the nutritional management of the bariatric patients will be provided from pre-operative to post-operative phase. Patients with severe obesity often display micronutrient deficiencies when compared to normal weight controls. Therefore, nutritional status should be checked in every patient and correction of deficiencies attempted before surgery. At present, evidences from randomized and retrospective studies do not support the hypothesis that pre-operative weight loss could improve weight loss after BS surgery, and the insurance-mandated policy of a preoperative weight loss as a pre-requisite for admission to surgery is not supported by medical evidence. On the contrary, some studies suggest that a modest weight loss of 5–10% in the immediate preoperative period could facilitate surgery and reduce the risk of complications. Very low calories diet (VLCD) and very low calories ketogenic diets (VLCKD) are the most frequently used methods for the induction of a pre-operative weight loss today. After surgery, nutritional counselling is recommended in order to facilitate the adaptation of the eating habits to the new gastro-intestinal physiology. Nutritional deficits may arise according to the type of bariatric procedure and they should be prevented, diagnosed and eventually treated. Finally, specific nutritional problems, like dumping syndrome and reactive hypoglycaemia, can occur and should be managed largely by nutritional manipulation. In conclusion, the nutritional management of the bariatric patients requires specific nutritional skills and the intervention of experienced nutritionists and dieticians.

Effects of Low-Carbohydrate versus Mediterranean Diets on Weight Loss, Glucose Metabolism, Insulin Kinetics and β-Cell Function in Morbidly Obese Individuals

“…Compared with standard dietary regimens, a LC/high-protein diet has generally demonstrated greater effectiveness in reducing body weight in the short term [ 6 , 15 , 16 , 17 , 18 ], which was attributed to the greater ability of protein to induce satiety and suppress hunger [ 22 ] and to increase thermogenesis [ 20 , 24 , 25 ] than carbohydrate and fat. In fact, in morbidly obese patients eligible to bariatric surgery, a LC diet is recommended as a feasible approach to obtain a 5–10% weight loss in the immediate preoperative period, which facilitates surgery and reduces the risk of complications [ 39 ]. The higher efficacy of LC diets on weight loss and maintenance was not consistently reported in longer-term studies conducted over a 6- to 24-month period [ 18 , 21 , 25 ].…”

Nutrological Management in Bariatric Surgery: A Narrative Review

“…The nutritional status must be verified in each patient and the correction of deficiencies must be attempted before surgery. Some studies suggest that a modest weight loss of 5-10% in the immediate preoperative period can facilitate surgery and reduce the risk of complications [12][13][14]. Low calorie and ketogenic diets are the most used methods for inducing preoperative weight loss.…”

“…Low calorie and ketogenic diets are the most used methods for inducing preoperative weight loss. Nutritional deficits depend on the type of bariatric procedure [12].…”

Mono and dual agonists of the amylin, calcitonin, and CGRP receptors and their potential in metabolic diseases

“…In contrast, amylin receptor agonism and particularly dual agonism of amylin and calcitonin receptors remain highly interesting, as the mechanism of action involves improved insulin sensitivity. As they perfectly complement other drugs with metabolic actions, they could help treatment-induced weight and glucose control match bariatric surgery-induced effects [ 186 , 187 ].…”