evidence: It's true! Oatmeal is one of the best foods in terms of longevity. According to a study published by the Nutrition Journal, oats can help decrease the risk of autoimmune diseases, heart disease, and even gaining more weight. Plus, having a regular intake of whole grains in your diet has been proven to inverse mortality rates, according to the American Heart Association. [...] Oatmeal brings many positive benefits to your health. With side effects like better digestion, potential weight loss, better heart health, and greater feelings of fullness, it's hard to deny that oatmeal is healthy. [...] Oatmeal may cause some belly bloat "If you are new to oats, they may cause bloating, so it's best to start with a small portion," says Lisa Young, PhD, RDN and author of Finally Full, Finally Slim.