Glycemic index of raw versus cooked food bars

Abstract

Glycemic index (GI) classifies foods by the extent that their ingestion affects glucose responses, and diets with lower GI foods may reduce chronic disease risk. Proponents of raw foodism suggest that raw foods provide such advantages but this concept is supported by limited research. This study was conducted to compare the GIs of two different commercial raw food bars (Larabar®) containing either dates, walnuts, apples, almonds, raisins, and cinnamon (Apple Pie) or cashews and dates (Cashew Cookie) consumed either raw or cooked (baked at 350°F for 15 min). Food portions containing 50 g of carbohydrate from a glucose solution (tested in triplicate) and the 4 trials of test foods were administered in random order to 15 healthy adult women after at least a 4‐hour fast. Capillary blood samples were collected at baseline and 15, 30, 45, 60, 90 and 120 min after consumption and assessed for glucose concentration. GI values were calculated from the incremental area under the curve by the trapezoidal method. Data were analyzed using paired‐comparisons t‐tests between raw versus cooked varieties of each bar. GI (mean±SD) was higher (p≤0.05) for the cooked (64±40) Apple Pie bar than its raw (42±32) counterpart. No difference was detected for cooked (42±24) or raw (39±20) Cashew Cookie bars. Cooking appears to raise the GI of some, but not all, food; therefore, research is needed to establish which foods yield elevated GIs after cooking.