Make it illegal to make statements that are not objectively true. E.g. you can't say that your product is "the best", you can only say specifically how it is better.
Put restrictions on advertising an idealized version of a product and then selling a lesser version. E.g. the difference between what fast food ads show versus what you get. I'm sure it would be difficult to completely fix that since it's so subjective, but we could probably get incremental improvements.
These are often lies too but its the subtext not the text