I) After BPD Protein-calorie malnutrition "PCM" is multifactorial and depends on patient-related factors (such as eating habits, capacity to adapt these to requirements set by the surgery, and socio-economic status) and technical factors (including gastric volume, bowel limb lengths, intestinal absorption and adaptation, and amount of endogenous nitrogen loss). Most cases are limited to a single or sporadic episode. In the early postoperative period secondary to the forced reduced food intake, the marasmic form of PCM incidence is higher, which is the aim of the operation. However, when carbohydrate intake is preferred (poor compliance with adequate protein intake), the hypoalbuminemic form will develop. The absorptive capacity of the alimentary limb "AL" and common limb or channel "CC" depends on 1) number of villi per square centimeter, 2) transit time, and 3) total intestinal length of the AL + CC. Thus, any condition that interferes with postoperative intestinal adaptation, mainly villous hypertrophy; increased transit time; and/or decreases the length of the functional AL + CC will lead to late onset of severe PCM. Increased number of bowel movements "BM" or severe diarrhea generally precedes to PCM.