It depends on which cold and which cooked cereal you are comparing. I recommend any cereal that is not sugarcoated but is enriched with iron, thiamin, riboflavin, and niacin. These nutrients are usually lost during grain processing.
A quick trip down the cereal aisle will tell you there are a lot of cereals to choose from in today’s market. Here are some suggested guidelines for choosing a cereal whether hot or cold. Look at the Nutrition Facts label on the cereal box. Most cold cereal will have information about what carbohydrates can be found in one serving. Starch, fiber, and sugars may be listed. Four grams of any sugar is equal to one level teaspoon of sugar and eight grams is equal to two teaspoons. I would suggest any cereal that has eight grams of sugars or less per serving, especially if the cereal has fruit such as raisins or apples in it. Not all hot cereals have the sugar content listed on the package. Some of the newer individually packaged instant cereals are very high in sugar. A guideline for any cereal that does not have the grams of sugar listed is to look at the list of ingredients, which are listed in decreasing order. If sugar or sweetener like corn syrup is one of the first three ingredients, don’t buy that cereal. Also, read the label for the word “sweetened” or “sugar added”.
I will admit that a bowl of cooked cereal seems appealing when it is below zero outside. I cannot prove, however, that cooked cereal “sticks to the ribs” longer than cold cereal. We do know, however, that high fiber foods do slow down your stomach emptying, which may add to your feeling full longer. Oatmeal is one such high fiber cereal that may delay your stomach emptying and give you the sensation of feeling full longer.