There are so many protein products on the market. What was once relegated to protein powders has transformed into a huge industry, with everything from protein-infused cookies and pancake mix, and now, soda. Protein soda is essentially a sparkling, sweetened beverage with added protein — but which ones are really worth drinking? Carmen Varner visited four grocery stores in San Diego County and ultimately found five cherry protein drinks from Summit Popz, Clean Simple Eats, Premier Protein, Proda, and Barebells to review. For each, the protein source is whey protein isolate, a by-product of cheesemaking that's essentially highly filtered, protein-rich whey with less lactose and fat than typical whey. In terms of criteria, Varner was looking for something flavorful and enticing to drink, with a fair amount of carbonation. She also factored in cost and nutritional value, including calories, sugar, and protein. See how they ranked from her least favorite to her top pick at the link i...