Jf. Horowitz et Ef. Coyle, METABOLIC RESPONSES TO PREEXERCISE MEALS CONTAINING VARIOUS CARBOHYDRATES AND FAT, The American journal of clinical nutrition, 58(2), 1993, pp. 235-241
After a 12-h fast six different meals (potatoes, rice, sucrose solutio
n, potatoes + margarine, rice + margarine, and a confectionery bar), e
ach containing 0.7 g carbohydrate/kg body wt, were consumed 30 min bef
ore exercise (n = 9). During the 30 min immediately after ingestion, t
he glycemic and insulinemic responses to the meals distinguished these
foods into two groups: 1) high glycemic (ie, potatoes, sucrose, confe
ctionery bar) and 2) moderate glycemic (ie, rice, potatoes + margarine
, rice + margarine). After 20 min of moderate-intensity exercise, plas
ma glucose declined in all carbohydrate trials to values of 3.4 +/- 0.
1 mmol/L, which were significantly (P < 0.05) lower than values after
subjects fasted (4.2 +/- 0.2 mmol/L). Therefore, the glycemic and insu
linemic responses to these meals were independent of their carbohydrat
e classification of simple or complex and the addition of fat reduced
the glycemic and insulinemic responses. However, despite these differe
nt responses before exercise, all of the meals caused plasma glucose t
o decline to equally low concentrations early in exercise.