What is the key difference between foods with a 'high glycemic index' and a 'low glycemic index'? 1) High glycemic index foods have a higher impact on blood sugar levels compared to low glycemic index foods. 2) High glycemic index foods have a lower impact on blood sugar levels compared to low glycemic index foods. 3) High glycemic index foods have a higher fiber content compared to low glycemic index foods. 4) High glycemic index foods have a lower fiber content compared to low glycemic index foods.