PARADE Magazine ran a Nov. 28, 2011 interview by Lynn Sherr, "Ann Romney Reveals Mitt's Softer Side," which included mention of some of Mitt Romney's favorite foods:

Asked, "What does he always have to have in the refrigerator?" Ann Romney answered:

"Low-fat milk because he’s a big cereal hound. He loves cold cereal. And caffeine-free Diet Coke. I’m always trying to get him to drink more water. That’s a struggle for me. [Note: The Governor’s current favorite cereals are Brown Sugar Chex Bites and Quaker Oatmeal Squares.]"

Sherr followed up, "Is that it? Come on, say something bad that he likes to eat or drink." To which Ann Romney responded, "Chocolate milk."  Seeking clarification Sherr asked, "Chocolate milk, but not whole milk, right?" and Ann Romney said, "No, Over the Moon Chocolate Milk, which is the low-fat kind."

Finally Sherr asked, "You two abstain from coffee and tea, so what does he drink to get himself going?"  The answer was, "Hot chocolate."

Around this same time, the "POLITICO Playbook 2012: The Right Fights Back" (a Random House eBook) contained some details of Romney's diet on the road:

"If he has a slice of pizza, he pulls the cheese off the top. Usually, Romney dines on turkey breast, rice, and broccoli, chased by water or maybe a Diet Coke. In South Carolina, for a big treat, he might visit a Bojangles‘ for the fried chicken. Romney relished KFC, but pulled off the skin.”