Procedure (see Jenkins et al):
(1) Ingest 50 grams of a reference carbohydrate (usually glucose or white bread) and monitor the serum glucose for 2 hours after eating.
(2) Draw a curve connecting the serum glucose values and determine the area under the curve using the pre-ingestion serum glucose as the baseline.
(3) On a separate day ingest 50 grams of carbohydrate in a portion of the food being evaluated. Monitor the serum glucose for 2 hours after eating.
(4) Draw a curve connecting the serum glucose values and determine the area under the curve using the pre-ingestion serum glucose as the baseline.
glycemic index for food =
= (area under curve for carbohydrate load from food) / (area under curve for reference carbohydrate source) * 100%
Interpretation:
• minimum glycemic index for most foods using glucose as reference source: 0
• maximum glycemic index for most foods using glucose as reference source: 100
• maximum glycemic index for most foods using white bread as reference source: 142
|
Level of Glycemic Index
|
GI referenced to glucose
|
GI referenced to white bread
|
|
high (Class I)
|
> 63
|
> 90
|
|
intermediate (Class II)
|
49 – 63
|
70 – 90
|
|
low (Class III)
|
< 49
|
< 70
|
from Table 86.9, Anderson; adapted from Wolever and Jenkins (1995)
