evidence: But it's not all good news for oatmeal. "While oatmeal is sold as a healthy option for some things, it does have an impact on our metabolism, and I advise caution" in eating too much, says Naidoo. Oatmeal is also known to cause gas and bloating, which can be especially problematic if you have gastrointestinal issues such as irritable bowel syndrome. One of the other downsides of eating oatmeal is its aforementioned bland flavor. This causes many people to add large amounts of white or brown sugar to sweeten it. The daily value limit of added sugars, as recommended by the U.S. Food and Drug Administration, is only 50 grams -about 12 teaspoons. It's not uncommon for people to put a quarter of that amount on a single serving of oatmeal. "Be mindful of how you prepare your oatmeal and what you add to it," advises Kristen Smith, MS, RDN, spokesperson for the Academy of Nutrition and Dietetics and registered dietitian at Piedmont Health. "Oatmeal can quickly become a higher calorie and sugar food if you aren't careful."