Q. Are diet sodas and snacks with artificial sweeteners safe for children?
A. There is probably not much immediate harm; there is no definite proof of medical disease of any sort in children to be caused by artificial sweeteners, except for an occasional allergic reaction. But I don't see a need for it.
Although an occasional diet soda is probably fine, I'm not comfortable with kids having lots of artificial sweetener, for three reasons:
1) Even though there's no studies showing actual harm, I'm anxious about the unknown effects of large amounts of these chemicals.
2) Even though artificial sweeteners have no calories, I worry that kids will get used to drinking sweetened drinks; if this becomes a habit, their learned preference for sweetened drinks may translate into excess calorie intake as older kids or adults.
3) There is some preliminary evidence that long-term use of artificial sweeteners may increase the risk of Type-II Diabetes, just as much as sugar does. The brain's hormonal response to the sweetness of the artificial sweeteners is similar to that of ordinary sugar.
People ask: "Which is best for kids: regular soda or diet?" But the question frames a false choice: to offer sugary drinks and snacks, or chemically sweetened ones. There is a third choice, which is the one I recommend: unsweetened drinks such as milk, water, or unsweetened ice tea and flavored waters, and snacks (such as fresh fruits, vegetables, and crackers) which have no additional sweetener.
-- Dr. Epstein