From my understanding Google now reads your HTML, CSS and JS files in an attempt to better understand your site. It really depends what you are hiding and why. You have to be very careful, if you are hiding body text that the page still properly represents the same information to all users. Google will not care if you are hiding a hero image from phones to increase load times. But if it feels you are hiding substantive content from some users it might penalize you. The best thing to do is to try your best to consistently represent your site to all users, hook your site up to webmaster tools and see if you get any warnings.
I would caution you, if your reason for hiding body text it to prevent scrolling, and therefor provide a better user experience. From my experience user expect to be able to scroll, and in some instances scroll for a very long time. Nothing is worse then making assumptions about what a mobile user wants to see vs a desktop user wants to see. If the text you are serving to desktop user is high quality and relevant then it should be served in the same way to mobile users. On the other hand if you can cut down the copy for your mobile users and still get your point across you should consider using your mobile copy for your other users as well.
I would love to hear other peoples thoughts on this.