Yes, oatmeal is a healthier food and milk is more nutritious and healthy. This collocation is no problem, but it is best to add some carbohydrates, such as steamed bread, steamed bread, or bread. You can also add eggs. If you don't want to lose weight like bread, you can add some fruit. In any case, this is a reasonable collocation and more kinds, not the same food forever. But I still suggest you eat some porridge tomorrow morning, because porridge is good for your stomach. I think the perfect combination in the morning is porridge, milk and eggs. It's purely personal.