Question: how many calories in a mcdonald's plain oatmeal?
Answer: Best Option: Make It at Home. The calorie count in McDonald's oatmeal is hardly outlandish, at 290 calories fully loaded with cream and fruit. Plain oats -- with no additives -- are 150 calories per serving, before adding any sugar, syrup or fruits. Bittman said the best option is to make it at home.