Gastric emptying of two whey-based formulas of different energy density and its clinical implication in children with volume intolerance

Objective Whey-based formulas have faster gastric emptying than casein-based formulas. Isoenergetic, isovolumic, whey-based formulas of different osmolarity and fat content empty in a similar manner. Will the gastric emptying of high and low energy density whey-based formulas be similar?Design We studied the gastric emptying rate of equal volumes of two whey-based formulas of different energy density (4.18 kJ/ml and 6.27 kJ/ml) and osmolality (270 and 450 mOsm/kg, respectively) in 10 children (4.5-12 y) with volume intolerance and resultant inability to gain weight.Results The two formulas had comparable gastric emptying rates at 30, 60, 90 and 120 min. Over a one month clinical trial, substitution of the lower energy density whey-based formula (no weight gain over 2 months) with an equal volume of the high energy density formula produced a mean weight gain of 1.17+/-0.5 kg per patient without change in tolerance.Conclusion The higher density whey-based formula can safely substitute an equal volume of a lower energy density formula to produce weight gain without affecting tolerance.Implication This provides an important intervention for increasing energy intake in children with volume intolerance or fluid restriction.