When KFC introduced the Double Down last year, we thought we'd seen it all. But in purely caloric terms, the Double Down — amazing in its imaginative, bunless splendor — doesn't hold a candle to the newest burgers to hit the market.

I was recently introduced to Smashburger's Sin City burger, which makes the Double Down look like a snack wrap. It's essentially everything bad for you all stacked together — a beef patty, a fried egg, cheese, applewood-smoked bacon, haystack onion, sauteed onions and some creamy, zest goodness called smashsauce — so of course it originates from the Las Vegas branch. All the extra goodies add a little vertical heft to the normally flat Smashburger, and though I find the double onions a little excessive, the fatty delicoiusness is undeniable.

At Burger King, the new Stuffed Steakhouse Burger has gotten attention for its beef patty stuffed with jalepeños and cheddar cheese. (Though how this differs calorically from adding cheese and jalepeños to, say, a Whataburger is not clear.)

It's a little odd this trend of gluttonous creations has taken hold, especially since fast food places have been working to clean up their image, adding salads and fruit cups as an alternative to fries and banishing the word "fried" in favor of "crispy."

Of course burgers that strain credulity (and mouths) with a lineup of unhealthy toppings are nothing new. Locally Hubcap Grill has had a burger called the Quadruple Heart Clogger (beef patty, grilled weiner, bacon, chili and cheese) on the menu for years and Lankford Grocery offers the Grim Burger with macaroni and cheese, bacon, a fried egg and jalepeño.

But for all our beefy consumption, Americans are still being eclipsed — by the Japanese.

While McDonald's in the United States is getting flack from Morgan Spurlock and the San Francisco City Council (who banned Happy Meals from including toys unless they met a minimum health content), across the Pacific they have rolled out a quartet of gargantuan burgers — named after American cities and regions, of course.

There alongside the Idaho burger (which includes a hash brown potato patty), the Miami (tortilla chips, spicy chili sauce) and the Manhattan (mozzarella, pastrami and sour cream sauce), a Texas 2 burger comes with chili beans, bacon, and onions served on a quarter-pound beef patty with cheese, grainy mustard relish and a Big Mac-style bun. It's a sequel to the popular Texas Burger from the original Big America hamburger collection and weighs in at 645 calories.

Is this part of McDonald's master plan to help other countries catch up to our obesity rate? Or have Americans been topped in cravings for beefy, fatty goodness? Apparently not in Sin City.