This versatile grain can be used in a wide variety of dishes—not just breakfast!—to add fiber to your diet to help you lose weight. Results will vary based on the person. Oatmeal is an extraordinary, whole-grain food that is rich in fiber, antioxidants, and selenium. Oatmeal is a favorite breakfast for many people, especially during the winter season. The idea behind the oatmeal diet is to eat oatmeal as your main course for one or two meals every day. The Oatmeal Diet Results. Oats are considered to be a whole grain with a number of nutritional benefits. The Oatmeal Diet has the potential to deliver serious results. During the 2 months on the plan, users report losing as much as 40 pounds. In the first week, dieters have reported losing up to 5 pounds. The oatmeal diet is a fad diet that involves eating only or mostly oatmeal. Oatmeal is made from dry oats.