Dumping syndrome, first described by Hertz in 1913, is defined by the occurrence of ‘dumping-like’ symptoms after gastroenterostomy, triggered by food reaching the small bowel too rapidly or in too high quantity [1]. Thus, the definition of dumping syndrome has its origin at the time of peptic ulcer surgeries (i.e., partial or total gastrectomy). Later and to date, other gastric surgical resections (e.g., bariatric or oncological interventions) have been associated with the syndrome [2,3].

There are two different subsets of symptoms and signs, classified as early and late dumping, respectively. Specifically, early dumping symptoms occur within the first hour after a meal. They include gastrointestinal and vasomotor symptoms [1,2]. The gastrointestinal early dumping symptoms encompass abdominal pain, bloating, borborygmi, nausea, and diarrhea; the vasomotor early dumping symptoms include fatigue, flushing, palpitations, perspiration, hypotension, and rarely syncope. Typically, during early dumping, the patient shows a strong desire/need to lie down after the meal because of the symptoms [[1], [2], [3]]. Late dumping consists of symptoms due to reactive hypoglycemia. The latter is a consequence of a preceding rapid rise in glycemia during the early dumping phase which is followed by an exaggerated and prolonged insulin response. The late dumping symptoms include perspiration, palpitations, tremor, irritability, hunger, fatigue, weakness, confusion, and may end up in hypoglycemic syncope [[1], [2], [3]]. Recently, late dumping occurrence after bariatric surgery has been referred to as “postbariatric hypoglycemia” (PBH) [4]. However, PBH is almost invariably associated with early dumping as a preceding and initiating factor of late symptoms [5].

Dumping syndrome incidence reaches up to 40 % of patients undergoing gastrectomy, and 50 % of patients after esophagectomy [6,7]. The latter is associated with the cutting of the vagus nerve, which regulates gastric secretions, gastric acid pH, and motility (namely, emptying). In the frame of antireflux surgery, dumping syndrome has been reported in both children and adults [8]. Indeed, bariatric surgery (i.e., Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy) have become the primary cause of postoperative dumping syndrome. The latter has also been referred to as its second phase as PBH [9]. Systematic and narrative review of literature describe the occurrence of early and late dumping after bariatric surgery [10,11].

Dumping syndrome diagnosis is based on recognition of the symptoms in an appropriate clinical context and confirmation through testing [1,2,[12]]. Clinical suspicion should be raised in patients with a history of upper gastrointestinal surgery (e.g., bariatric and oncological). Symptoms range from meal-induced gastrointestinal and cardiovascular and those suggestive of hypoglycemia. Marked fatigue upon meal ingestion and the need to lie down are two important and typical symptoms suggestive of dumping syndrome. In the 1970s, a symptom-based diagnostic index for patients undergoing vagotomy was proposed by Sigstad [13]. However, the diagnostic performance of the score in patients with dumping syndrome due to other types of surgery has not been assessed to date. Moreover, in 271 patients' post-bariatric surgery, there was no correlation between Sigstad diagnostic index score and late dumping symptoms [14]. Measurement of spontaneous hypoglycemia at the time of symptom occurrence can confirm suspected hypoglycemia. A recent international multidisciplinary Delphi consensus agreed for a threshold glycemia of 2.8 mmol/L (50 mg/dL) or lower as abnormal [16]. A modified, prolonged oral glucose tolerance test (OGTT) can be used to confirm the hypoglycemia[1,2, 16]. Indeed, the glucose provocative test has been criticized because of low specificity and possible over-diagnosis of dumping syndrome [15,16]. Further, the test does not define a postprandial cutoff value of hypoglycemia for late dumping. To increase specificity, the assessment of hypoglycemia together with symptoms, relieved by carbohydrate ingestion, can be used to indicate late dumping (specifically, Whipple's triad) [17]. An alternative to the OGTT is a mixed meal provocative test, mainly as a measure to induce hypoglycemia typical of late dumping [20].

Dumping syndrome management is complex, challenging and nutritional approach affects patients' symptoms at the beginning of the treatment and in severe and refractory cases. Unfortunately, evidence on the impact of this approach on dumping syndrome is variegate and lack consistent randomized controlled trials. Some advice is experience-based rather than evidence-based. Thus, the aim of the manuscript was to review literature data on the role of diet, its modifications, and the use of dietary supplements enhancing food viscosity on patients’ symptoms, starting from mild until severe and refractory cases. Finally, a focus on data on PBH dietary management and the use of enteral feeding in dumping patients has been made.