evidence: One caveat: There is a chance oats may increase weight gain when eaten in excess. A study from Cornell University that was published in the journal Physiology & Behavior looked at the eating behaviors that lead to weight gain or loss (like eating a salad first, or brushing teeth instead of snacking). (12) People who said they ate oatmeal for breakfast gained 0.83 pounds over a month. Instructing people to eat oatmeal may encourage mindless overconsumption — especially if its health halo makes you forget about portions. (Too many high-sugar toppings can also do it.) [...] There are few reasons to fear oats, unless you have a specific food allergy to oats. If you are avoiding gluten due to a medical reason, oats are often the victim of cross-contamination with products that contain gluten (wheat, barley, or rye) during processing. In that event, it’s critical to consume oats that are specifically labeled gluten-free. (13) Certainly, eating overly large servings of oats can lead to weight gain, as can topping it with too many fatty or sugary treats. [...] Q: Is oatmeal healthy?