Cheerios and Fruit Loops are both breakfast cereals. Cheerios are somewhat bland and beige in color. fruit Loops are colorful and sweet. I suspect this means you hold try to stand out from the crowd, be unique.

Susan is correct in her answer. The sentence is idiomatic. The literal words convey a different meaning to what they are. Here are some other such expressions http://www.english-grammar-revolution.com/idiomatic-expressions.html

Wow. Richard, your kind explanation made me motivating. I'd like to study Eng more. Thank you so much! :)

The definition of "cereal" is "any plant of the grass family yielding an edible grain, as wheat, rye, oats, rice, or corn." "Breakfast cereals" such as corn flakes, Fruit Loops, Cheerios, etc. are cereals which are is milled and packaged for consumption. Wheat, oats, rice and corn are all used in a number of breakfast cereals. I don't know of any breakfast cereals that use rye or barley. Many breakfast cereals have lots of added sugar which has caused them to become less popular in recent years due to health concerns regarding overconsumption of carbohydrates. Most people eat breakfast cereals with milk or alone.