Magouliotis et al. found OAGB to result in an increased incidence of malnutrition in a meta-analysis including >12,000 patients; yet only 1 study clearly defined malnutrition, and the definition was serum albumin < 30 g/L or pre-albumin < 0.2 g/L, which have relatively low sensitivity and specificity in detecting a malnourished state [13,14]. The gene discussed is ALB; the disease is nutritional deficiency disease.