evidence: What’s So Bad About Oats? Oats seem to be getting a bad rap across social media recently. Whether you are a loyal oat eater or thinking about including them in your routine, it’s understandable to wonder whether they are the best option out there. [...] Many dislike oats because they contain phytic acid which impairs the absorption of iron, zinc, calcium, and more. It also blocks the production of digestive enzymes, making oats much harder on your stomach.