Healthy food and market capitalism are inherently incompatible...
The solution is moderate consumption of natural traditional foods, things that our bodies have evolved over thousands of years to consume. But moderate consumption is unprofitable, the market system forces companies to:
1) encourage excessive consumption, more consumption = more profit
2) look for ways to cheapen the product to either improve margins, or compete against others
The end result is always going to be junk packed full of the cheapest possible ingredients that are not illegal or outright poisonous.
Government regulation could solve this if done properly, but usually makes things worse because current regulation focuses on saying "X is bad, reduce X", which means X gets replaced with Y where Y is something new that hasn't been studied enough to make it onto the bad list yet.
There are also things like coloring that exist solely for marketing to make the product look more appealing, but serve no nutritional purpose and could be harmful. The use of artificial coloring should really be eliminated entirely.