Very Low-Calorie Diet, the Morbidly Obese With Liver Cirrhosis and Bariatric Surgery
Morbid obesity defined on the basis of the body mass index is still considered in several centers a contraindication to liver transplant (LT). Although obese patient candidates for LT are requested to regulate their diet to lose weight before being listed, there is no consensus on which is the best index to identify patients at risk of complications linked to obesity as well as on how best to achieve the desired weight loss. In this setting, although some authors have suggested the use of bariatric surgery, the timing and the type of procedure as well as the identification of the best candidates to this strategy are still under debate. Concerns have been raised that very low-calorie diets (VLCDs) yields a catabolic state, with significant nutritional risks, such as a greater and rapid weight loss that may be accompanied by significant loss of fat-free mass (FFM) and/or sarcopenia. Indeed, LT candidates are at high risk of sarcopenia and malnutrition, which may be then worsened by VLCDs. Although the authors set the cutoff at 1000 kcal/d in obese patients with compensated cirrhosis, we believe that the quality of the diet in terms of macronutrient composition is of mainstay importance more than the amount of Kcal to avoid muscle wasting and sarcopenia. In fact, the amount of proteins in the diet seems to be a main determinant to maximize fat mass loss while preserving metabolically active FFM. Weinheimer et al2 showed in a systematic review, that in VLCDs, most of the weight loss concerns the FFM and not fat mass. Instead, Mettler et al3 demonstrated that consuming dietary protein at 2.3 g·kg−1·day−1 is superior to 1.0 g·kg−1·day−1 (recommended dietary allowance) for the maintenance of FFM in young athletes. Pasiakos et al4 demonstrated in volunteer military personnel from the U.S. army that consuming 1.6 g·kg−1·day−1 (twice the recommended dietary allowance) is enough to protect FFM during short-term weight loss. While the transposition of these data to the cirrhotic patient is not easy, the literature is very scanty on this topic. Temmerman et al5 reported in 2 obese patients with cirrhosis that the use of VLCDs (800 calories daily, 25% carbohydrates, 45% protein, 30% fat), under close medical supervision, was safe and effective in reducing weight and improving the MELD score without any associated adverse effect even on FFM. This debate remains of utmost importance in the case of morbidly obese patients with compensated cirrhosis to whom bariatric surgery may be eventually offered to increase candidacy to LT. Indeed, after any bariatric procedure the amount of calories that can be ingested is limited during the first 6 months after surgery when the loss of weight is maximal and certainly below the threshold of 1000 Kcal/day. As a consequence, the type of diet is this setting is very close to the VLCD model. Close medical supervision and correct diet composition in terms of macronutrients become determinant for the safety and effectiveness of this strategy to reduce weight, increase candidacy for LT, and possibly improve liver damage.