Looking in a fun house mirror?

In a recent study, only 15 percent of obese adults actually defined themselves as being that way. The other 85 percent apparently all have those fun house-type mirrors that make you look skinnier — much skinnier — than you really are.

So, how do you tell if you're obese? Well, officially, you're that way if your Body Mass Index is 30-plus. To figure this out in your head, just divide your weight (but not the weight shown on your driver's license) by your height-in-inches squared (without high heels on) times 704.5 (or about the number of calories in your mid-morning snack). If the number's too high, it must be a faulty formula.

You also know you have a weight problem when . . .

• You use your belly instead of a belt to hold up your pants.

• You have a food octagon instead of a food pyramid.

• Spelunkers ask if they can explore your not-so-mini "innie" belly button.

• You find your midsection listed on Mapquest.

• Guess-your-weight staff at amusement parks have to work overtime on you.

• Your scale is a special, limited "Port of Entry" edition.

• You buy clothes a size too big so you have room to grow.

• You've gained, lost and regained more weight in a calendar year than Paris Hilton weighs.

• You've eaten more in one meal than Paris Hilton weighs.

• You've spent more money in weight-loss products, diet programs, calorie-burning pills, Richard Simmons tapes and/or videos, Oprah Winfrey self-help books, infomercial fat-zapping items, exercise gadgets, fat-free mayonnaise, cabbage soup and Diet Coke than Paris Hilton's worth.

• You rank your body's metabolism somewhere between Darth Vader and Freddie Kruger in the list of worst-ever villains.

• The most important women in your life are: your wife, your mother, Mrs. Fields, Betty Crocker and Aunt Jemima (and not necessarily in that order).

• You've eaten a rice cake.

• You kept munching until the whole package, including the package, was gone — and you didn't know which tasted better.

• You've stood in a casting-call line for "The Biggest Loser" far-from-reality show.

• You've cursed Jared for getting thin and rich, but you've tried his Subway diet anyway.

• You dream of Gino's.

• You call adventurous-but-risque swimming "chubby dipping."

• You've asked if there's anything bigger than "super-size."

• Weight Watchers executives, Fergie included, know you by first name and send postcards thanking you from their luxurious vacation spots.