I would like to assume that people aren't generally so ignorant of how insurance works that they think the risk of eating two big macs a week could be accuratel

I would like to assume that people aren't generally so ignorant of how insurance works that they think the risk of eating two big macs a week could be accurately priced in and that insurance companies would not just use the fact of eating a couple to justify an unsupported by actuarial analysis rate increase. Once again, my assumptions of people prove misguided.