Humans have been domesticating apples for thousands of years,selecting them for increasing sugar content. Indeed, apples contain plenty of sugar, but because of their acidity and high content of soluble fiber, they don't raise the blood sugar much. The glycemic load of apples depends on their size and sweetness. Small ones of the tarter varieties such as Granny Smiths and Jonathons, have glycemic loads as low as 40. Large members of some of the sweeter varieties, such as Fuji and Gala, probably push 100. Nevertheless, for most people concerned about their weight or blood sugar, the health benefits of apples--their high content of vitamins, potassium and fiber--outweigh concerns about their sugar content.