TIME OF DAY INFLUENCES RELATIVE GLYCEMIC EFFECT OF FOODS

To see if time of day affected the relative glycaemic effect of foods, we studied 8 non-diabetic subjects in random order on 4 days over a 2 -week period. They were given 50g carbohydrate portions of corn or oat -psyllium cereal plus 200ml 2% milk. Each test meal was taken either a t 08:00h after a 10-12h overnight fast, or at 12:00h, 3.5h after a sta ndard breakfast. The incremental area under the glycaemic response cur ve for corn cereal taken at breakfast was greater than that at lunch, 103+/-13 versus 52+/-6 mmol . min/L (p<0.01), with the respective valu es for oat cereal being 52+/-12 and 41+/-11 mmol . min/L (ns). The res ponse to the oat cereal was 50% less than that of the corn cereal (p<0 .01) when taken at breakfast, but the difference at lunch, 21%, was no t statistically significant. Thus, time of day may influence the absol ute and relative glycaemic responses to foods in non-diabetic subjects . Further studies are needed to see if the same occurs in persons with diabetes.