A person making $75k per year with no kids would pay the exact same tax as someone making the same amount with kids, assuming they both spend all of their money in the year. Someone in the middle class will end up paying a lot more tax than they do now, it would seem.
The monthly prebate check is larger for the family with children and offsets the difference. If we gave exceptions for food or anything for that matter, like interest, then that would open the door for lobbyists to create loopholes. No exceptions closes the door for special interests.