How could people consume sugar in massive quantities from soft drinks and not get sick?

As I am hypoglycemic, I have a hard time understanding how it is possible for some people to consume a 20 oz. bottle of soda per day, and not get sick. If I were to consume the same amount of soda, the high sugar content would probably be enough to give me a hypoglycemic episode. Why is it that some people seem to be able to have as much sugar as they want, while some people have to be very careful about their carbohydrate intake?