The effect of meal energy content on gastric emptying.

Gastric emptying (GE) has been reported to be influenced by meal weight (grams) and composition (% carbohydrate:protein:fat) but the effect of meal energy content (kcal) on gastric emptying, independent of composition, has not been thoroughly investigated by scintigraphic techniques. In order to determine the effect of caloric content on GE, 12 normal male volunteers, ranging in age from 19-28 yr (mean = 24 yr), had GE scans (n = 32) performed with a solid meal of fixed composition (carbohydrate 40%:protein 40%:fat 20%) but varying energy content [150 kcal (n = 9), 300 kcal (n = 14), and 600 kcal (n = 9)]. Increasing the energy content of the meal of fixed composition progressively delayed gastric emptying: T1/2 = 57', 70', and 95' for 150 kcal, 300 kcal and 600 kcal, respectively (p less than 0.05; Student's t-test). Reproducibility, evaluated by performing GE scans (n = 8) on different days in the same individual (n = 4) with the same meal (300 kcal), was good (r greater than or equal to 0.89). Variability varied inversely with meal energy content (CV:150 kcal greater than or equal to 300 kcal and 600 kcal). The 300 kcal mean seems to be the best compromise since it results in less intersubject variability than 150 kcal, has minimal intrasubject variability, but is not as prohibitively large as the 600 kcal meal.