Peruse a rack of protein bars at any grocery story and they all blend together: claims of what the food does (or does not) contain, promises of protein, and some stamp of approval by the latest fad diet. Rxbar, founded in 2013 by Peter Rahal and Jared Smith, used to be one of them. But 18 months ago, the Chicago-based company gave its protein-bar packaging a radical overhaul, and they soon began landing in retailers including Whole Foods and Trader Joe’s…READ MORE