May I allow my children to eat candy?
Guarding one’s health, according to the Rambam, is midarchei avodas Hashem (a part of our Divine service). It’s a mitzvah to look after one’s health, and in some respects it’s more important than other mitzvos, since neglecting one’s health poses a sakanah (danger). In fact, Torah places a higher priority on avoiding danger than on avoiding other prohibitions, as it says, “Chamira sakanta mei’issura” (a danger is graver than a prohibition). Specifically, the Rambam says that unhealthy food should be regarded as a deadly enemy and interprets the pasuk (verse) “Shomer piv u’leshono shomer mitzaros nafsho” (He who guards his mouth and tongue guards himself from harm) as a caution against harmful eating habits, such as overeating or indulging in unhealthful food.
However, it would be wrong to argue that it’s therefore forbidden to give sweets to children. Doing so is clearly an accepted practice among Jews, so we can’t go so far as to say that it constitutes endangering lives. We must obviously educate our children about healthy eating, but there’s room for giving them treats in moderation.