While eating frozen meatballs occasionally is fine, it is best to eat them relatively sparingly. Depending on the brand, frozen meatballs can contain high amounts of sodium, saturated fats, and cholesterol, which are all bad for health.
Frozen garlic bread is generally not considered all that healthy. It is often made with white bread and contains artificial flavoring, which will only give you empty calories. Quality garlic bread eaten in moderation is nonetheless perfectly okay to enjoy.