A 39-year-old patient with a personal history of type 2 diabetes mellitus of 3 years' evolution with poor metabolic control, thrombophilia due to mutation of the prothrombin gene, super-morbid obesity (body mass index [BMI] 52 kg/m2) and Ulcerative Colitis (UC). She had been under follow-up in endocrinology consultations since the diagnosis of her diabetes. As treatment, she had been recommended diet and regular physical exercise, premixed insulin in 2 doses, metformin, omega-3 fatty acids, fenofibrate, mesalazine and omeprazole. The patient went to a private clinic for bariatric surgery, where she underwent laparoscopic biliopancreatic diversion without cholecystectomy one month after the last flare-up of her UC, and the postoperative period was uneventful. The patient required hospital admission 10 months after surgery due to oedematisation of the lower limbs secondary to protein malnutrition and aggravated by acute gastroenteritis. She was admitted to our care again one month later from the outpatient department for persistent severe hypoalbuminaemia. Since the surgery, she had not presented any outbreak of UC. He reported 2-3 semi-soft stools and denied vomiting or food intolerances. He had discontinued his antidiabetic treatment and was in remission according to the American Diabetes Association. On physical examination, general condition was acceptable with mucocutaneous pallor, blood pressure 99/62, heart rate 57 beats/minute, weight 63 kg (percentage of overweight lost 92.4%), height 1.61 m and BMI 24.32 kg/m2. Lower extremities with oedema with fovea up to the knees. Laboratory tests on admission showed total protein: 4.4 g/dl (Normal Range [NR] 6.4-8.3); albumin: 1.4 g/dl (NR 3.4-5.0) and prealbumin of 5 mg/dl (NR 20-40). He also presented anaemia without iron deficiency with a haemoglobin of 9.8 g/dl (NR 12.0-18.0). With a diagnosis of severe calorie-protein malnutrition, treatment was started with a high-calorie, high-protein diet, in addition to the administration of protein powder modules (60 grams per day). During her hospital stay, which lasted 3 weeks, the patient evolved favourably, remaining stable and with disappearance of oedema. At discharge, the patient was in good general condition and showed analytical improvement in nutritional parameters. Bone densitometry performed during her admission was normal.