When Alan Wong, general manager of Kung Fu Plaza in Las Vegas reads that someone doesn't care for Thai food because it's too spicy, sometimes he shakes his head. Other times, he throws his hands up in the air. And occasionally, he laughs.

"If you want to know whether a Thai restaurant is authentic or not, the first giveaway is if they try to turn up the spice on every dish," says Wong. "Some Thai food is spicy. Some Thai food is not. But any restaurant attempting to turn up the heat on not-so-spicy Thai food is probably trying to hide something else."

Most often, Wong says, too spicy might mean questionable quality. The heat tends to hide some of the flavors. Other times, it is the result of an over-simplification of Thai food, defining it as always attempting to balance hot, sour, salty, and sweet.

"That is not really true," explains Wong. "We actually focus on those four flavors and also bitter. Sometimes a dish might include a balance of all four flavors. Sometimes one flavor dominates a dish."

Wong says that when Thai cooking became popular in the United States, many individual cooks over-emphasized spicy to help set the cuisine apart from Chinese food. And while Wong says chilies are used in many dishes, the most common ingredient in Thai food is not chilies at all. It's fish sauce.

"One of our most popular soups is tom yum, which we make with lemongrass, mint, chili, straw mushrooms, and a choice of meats, with shrimp being traditional," says Wong. "Tom kha, on the other hand, includes coconut milk to make the soup heartier and richer, and is not usually as spicy as tom yum. Less heat brings out completely different flavors."

According to Wong, all regions have a variation of this classic recipe. For example, Bangkok cooks are more likely to emphasize the citrus flavors in a sweet and sour soup they call tom yam goong. Another soup, gaeng jued kai, which is not made at his restaurant, has no chilies at all.

Wong says trying to pin down how soup (especially sweet and sour) is prepared in Thailand is almost like trying to pin down what to put on a hot dog in America. On the East Coast, celery salt is commonplace and New Yorkers scoff at mild mustard. Head to the West Coast and Seattle, and you can find them with cream cheese and green onions. But to the rest of the world, an American hot dog is yellow mustard, ketchup, onions, and maybe relish.

"My point is that we all start to characterize international foods a certain way," says Wong. "The funny part is that we are most often wrong. Yes, many Thai recipes include chilies and curries, but not all authentic Thai dishes are hot or spicy."

In Las Vegas, Kung Fu Plaza is the oldest and most authentic Thai and Chinese restaurant. Originally opened in 1973, Kung Fu has had several locations over the years, including at the very top of Union Plaza in Downtown Las Vegas. Today, it is located at the entrance to Chinatown, which allows the legendary restaurant to deliver to almost any hotel room on the Las Vegas Strip.