Updated

Unless you’ve been living under a rock, you probably know that burgers aren’t exactly good for you. They’re loaded with fat, calories, saturated fat, trans fats, and cholesterol, and cheese and bacon just add insult to injury.

But they're still delicious.

Fast food chains are America’s biggest sellers of burgers, so we’ve tracked down some of the unhealthiest.

Burgers have been a fast-food mainstay for as long as fast food chains have been around. The original fast food chains, ones like A&W (1919) and White Castle (1921), sold basically just burgers and fries, and today a fast food chain that doesn’t sell burgers is considered slightly outside the box, or as Taco Bell puts it, “outside the bun.”

Today, fast food chains are having a bit of an identity crisis, torn between the highbrow and the lowbrow. On the higher end of the spectrum, we’ve got a dedication to fresher and more responsibly sourced ingredients.

But on the lowbrow end, we’ve got giant, usually deep-fried novelty items like Burger King’s new Mac ‘n Cheetos. Big burgers tend to lie somewhere in the middle; most non-chain burger places sell half-pound burgers with creative toppings, and fast food chains are trying harder and harder to compete with them.

The bigger a burger gets, the more calories it contains. But the sheer amount of calories in these burgers may surprise you. And just because they’re from fast food chains doesn’t magically make them less healthy than the burger at your favorite diner or burger place-- just about all restaurant burgers are made with at least 20 percent fat, and grease is grease.

Read on to learn about the highest calorie burgers at some of the nation's top fast food joints.

1. Hardee’s/ Carl’s Jr.: Monster Thickburger

89075e44-

(Hardee's)

Hardee’s and Carl’s Jr.’s legendarily unhealthy 2/3rd-pound Monster Thickburger is a beast of a burger, and contains an insane amount of calories: 1,340, to be exact. It also clocks in at 96 grams of fat, 34 grams of saturated fat, 275 milligrams of cholesterol, and 3,130 milligrams of sodium, more than double the American Heart Association’s suggested daily intake.

2. Sonic: Bacon Double Cheeseburger With Mayo

28d76418-

(Sonic)

Sonic’s Bacon Double Cheeseburger with mayo is planted firmly in the “Poor Decision” category, with 1,240 calories, 87 grams of fat, 35 grams of saturated fat, 3.5 grams of trans fat, 255 milligrams of cholesterol, and 1,690 milligrams of sodium.

3. Wendy’s: Dave’s Triple

06557a53-

(Wendy's)

The more patties, the more calories, as proven by this triple-decker from Wendy’s. Dave’s Triple (with three quarter-pound patties) contains 1,070 calories, 72 grams of fat, 30 grams of saturated fat, four grams of trans fat, 260 milligrams of cholesterol, and 1,930 milligrams of sodium.

More from The Daily Meal

The 101 Best Burgers in America

America’s Most Expensive Burgers

America’s 10 Best Restaurant Veggie Burgers

The 25 Best Cheeseburgers in America

10 Monstrous Burgers Around the World

4. Jack in the Box: Sirloin Cheeseburger With Bacon

240b4f88-

Salinas, United States - April 8, 2014: Jack in the Box Restaurant exterior. Jack in the Box is an American fast-food restaurant chain with 2,200 locations, primarily serving the West Coast of the United States. (iStock)

Jack in the Box’s Sirloin Cheeseburger with Bacon weighs in at 1,030 calories, 71 grams of fat, 23 grams of saturated fat, 2.5 grams of trans fat, 145 milligrams of cholesterol, and a whopping 2,400 milligrams of sodium.

5. Dairy Queen: Half-pound Flamethrower Grillburger

a3ec5663-

(Dairy Queen)

Cracking the 1,000-calorie mark is DQ’s ½ lb. Flamethrower Grillburger, two quarter-pound patties stacked with pepper Jack cheese, jalapeño bacon (whatever that is), and mayo-based FlameThrower sauce. It contains 1,010 calories, 71 grams of fat, 26 grams of saturated fat, two grams of trans fat, 165 milligrams of cholesterol, and 1,670 milligrams of sodium.

Check out more of the country’s unhealthiest fast food burgers (SLIDESHOW)