Semicolon indicates a support. It’s providing an example of the idea that was expressed before it. The author is describing the misconception with an example. Hope that helps a little!
Makes sense. How do I know if the author is describing the misconception or just supporting the whole idea that is the part before the semicolon?
People have a misconception that eating large amounts of healthy food will lead to longevity: the healthier they eat, the healthier they become.
Notice the above example. I am introducing an idea, then I am expanding that idea with an example. Isn’t that describing the nature of the problem?
I think you’ll get used to ETS style writing, keep practicing and noticing these patterns. Usage of a semicolon is usually done to provide example or expand the part before it.