I'll push back on this one - here in the UK, it is far cheaper to feed a family unhealthy food than it is to provide a nutritious well balanced diet. That isn't to say it can't be done - just that it is much harder. When a packet of 6 apples is £2 and a family sized packet of biscuits is £0.50 we have a problem.

That doesn't make it an oppressive system, it does make it a biased system and there are steps and measures that perhaps could be taken to address this. That said, I'm a libertarian and think people should be allowed to eat whatever they choose and shouldn't be forced into eating healthy. But they shouldn't be forced into eating unhealthily either - and that includes by not providing enough access to education, culinary skills or financial incentives to make different choices.