Diabetes Care, Vol 7, Issue 3 221-223, Copyright © 1984 by American Diabetes Association
The effect of cooking upon the blood glucose response to ingested carrots and potatoes
S Vaaler, KF Hanssen and O Aagenaes
Ten insulin-dependent diabetic subjects were given the following tests in
randomized order: 50 g glucose dissolved in water, 250 g raw and cooked
potato (equal to 50 g carbohydrate), 270 g raw and cooked carrot (equal to
25 g carbohydrate), and 4 h of fasting. Blood glucose was measured for 4 h
following the tests. The postprandial blood glucose responses after pure
glucose and cooked potato were almost similar (90-min values: glucose 8.8
mmol/L, cooked potato 8.0 mmol/L), while the response after raw potato was
considerably slower and weaker (90-min value: 3.3 mmol/L). There were no
differences between the postprandial blood glucose responses after raw and
cooked carrot (90-min values: raw carrot 3.2 mmol/L, cooked carrot 2.8
mmol/L), but the responses were statistically different from blood glucose
values during fasting alone (90-min value: 0.8 mmol/L). The study shows
that cooking is responsible for the rapid increase in blood glucose after
ingestion of cooked potato, while no such phenomenon is seen after cooking
of carrots.