Nutritional deficiencies are common in patients who are obese and therefore individuals considering bariatric surgery may require dietary supplementation with multivitamins and minerals before surgery. Nutritional deficiencies following bariatric surgery are often proportional to the degree of malabsorption created by the surgical procedure or the extent of weight loss. Eating habits often contribute to nutritional deficiencies, so appropriate dietary and lifestyle counselling are essential following bariatric procedures to ensure appropriate macronutrient and micronutrient status. Nutritional supplementation following bariatric surgery commonly includes calcium with vitamin D, iron and vitamin B12 in addition to a daily multivitamin and mineral tablet. Although general guidelines exist, individual monitoring and tailoring are frequently required. This article provides an update of guidelines regarding the most common nutritional concerns and myths surrounding bariatric surgery.