Dr. Greene`s Answer:
Strawberry or chocolate milk still has less sugar than most juices and lots of protein and calcium. Getting plenty of calcium is very important during the teenage years because the bone density formed then needs to last kids for the rest of their lives.
Most teens are not getting enough calcium. The latest recommendation is to get 1300 mg per day. There are about 300 mg in a glass of milk.
For children who dislike plain milk, flavoured milk provides a reasonable and healthy alternative. A large study of over 7500 children found that those who drank plain or flavoured milk had higher intakes of calcium and other important nutrients than children who didn’t drink milk at all. Drinking plain or flavoured milk was also associated with comparable or lower rates of obesity than drinking no milk.1 So the short answer to your question is that it’s better for your son to drink flavoured milk than to not drink milk at all. The good effects of flavoured milk definitely outweigh the bad.
1 Journal of the American Dietetic Association. 108(4):631-9, 2008 April