(Image credit: Charles Dharapak/AP Photo)

While we hear more than enough about the Republican presidential candidates' take on health care, the economy marriage and even contraception, we don't know a whole lot about how they fuel up to campaign around the country.  With their grueling travel schedule, it's easy to see how fast-food restaurant chains can become the restaurant du jour.

From Newt Gingrich's love of ice cream and Diet Coke to Mitt Romney's endorsement of Carl's Jr., we've investigated the candidates favorite foods and local jaunts in which to grab a bite to eat.

Newt Gingrich

This January Newt Gingrich showed his sweet tooth when he was spotted with two scoops of Moose Tracks ice cream from Elly's Tea and Coffee House in Muscatine, Iowa.  Although his favorite flavor is Black Cherry, he splurged on its popular Moose Tracks flavor made with vanilla ice cream and chocolate peanut butter cups swirled with chocolate fudge.

But Gingrich won't be visiting ice cream shops anytime soon. "I am going to give up desserts. .. all desserts," Gingrich told NBC when asked what he was giving up for Lent.  Gingrich's wife later said they would not be giving up food from the couple's favorite fast-food chain, McDonald's.

When he's not grabbing fast food or an ice cream cone, Gingrich loves drinking Diet Coke.  A campaign ritual, "The best prep for Newt is a Diet Coke and time to think,"  Kellyanne Conway, a senior adviser to Gingrich, told the New York Times.

Recipe:  After Lent, Gingrich is probably going to want to try this Bourbon Pecan Pumpkin Pie Milkshake.

Ron Paul

While his favorite meal is shrimp and rice, Ron Paul has a sweet tooth and loves chocolate chip cookies: "I am very soft on chocolate chip cookies," Paul has said.

The Paul campaign's press secretary Gary Howard  said Paul "favors soups and salads and often eats light.  Compromises often have to be made in favor of the never stopping clock, so fast food inevitably finds its way onto the plane … but the congressman always finds time for exercise!

"The congressman has enjoyed the freakishly fast service at Jimmy John's Sandwich Works in several cities and always looks for his old stand-by Ruby Tuesday's.  All-star staff picks include smoked salmon from Fairbanks's Pump House; poutine from Seattle's Skillet Diner; burgers and bacon-dusted fries from Portland Maine's Nosh; and the western charm of Phoenix's San Tan Flat," said Howard.

A big fan of breakfast, Paul was upset when that  first meal of the day  was interrupted at an Embassy Suites in Des Moines, Iowa.  Reporter Beth Reinhard wrote how Paul responded after he was questioned: "He looks up from his plate of cantaloupe, honeydew, eggs, sausage and biscuits and says brusquely, 'Right now, the only thing that bothers me is people who don't respect my privacy enough to leave me alone for five minutes when I'm eating breakfast.'"

The only candidate to add a cookbook to his credentials, the Pauls  one this year titled "The 2012 Ron Paul Family Cookbook" for $8.  The 28-page cookbook contains family favorites such as  raspberry scones, meatloaf and frittatas.

Recipe:  Ron Paul would love these Chocolate Chip Cookies.

Mitt Romney

Mitt Romney is a public supporter of Carl's Junior and has tweeted about his love of the chain along with a photo, "CarlsJr jalapeño chicken sandwich is delicious."  He also ate a Carl's Junior burger and fries after the Reagan Library debate.

After thanking Subway for breakfast, Romney tweeted a thank you to Subway:  "Better than the usual campaign diet of morning donuts."

Despite frequenting fast-food chains like Carl's Junior and McDonald's, Romney tries to make healthy food choices.  He regularly chooses grilled chicken sandwiches or pulls off the skin on fried chicken.

A big fan of barbecue, he toured Hudson's Smokehouse in Lexington, S.C., where he said, "I'm not a catfish man, or actually I'm not a  fish man, so much - I mean, I eat it 'cause I'm told it's good for me, but you know I still like the pulled pork."

For his "Grab a Bite With Mitt" contest, Romney enjoyed the pulled pork burrito with no cheese at the Dos Amigos Burrito restaurant in Concord, N.H., with the winner.

When he does indulge in snack food, Romney says "I love good pretzels and peanut M&M's."

Recipe: Romney's going to love this Pulled Pork Sandwich.

Rick Santorum

While not much is known about the way Santorum dines, he does have a salad named after him at Pizza Ranch.  Santorum tried a chicken and mayonnaise salad at the restaurant in Boone, Iowa, and after he said he liked it, it shortly named the salad after him.

He also loves chicken wings, as he ordered wings with a cold glass of water while watching a football game at Buffalo Wild Wings in Ames, Iowa.

When he splurges on junk food, Santorum says chocolate is his favorite: "I am a junk food addict. Most everyone says milkshakes, ice cream, that's probably bad. The deepest chocolate you can get."

Recipe:  Santorum would probably enjoy this Flourless Chocolate Cake.